WO2014028972A1 - An apparatus for radio break-in - Google Patents

An apparatus for radio break-in Download PDF

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Publication number
WO2014028972A1
WO2014028972A1 PCT/AU2013/000929 AU2013000929W WO2014028972A1 WO 2014028972 A1 WO2014028972 A1 WO 2014028972A1 AU 2013000929 W AU2013000929 W AU 2013000929W WO 2014028972 A1 WO2014028972 A1 WO 2014028972A1
Authority
WO
WIPO (PCT)
Prior art keywords
vehicle
unit
radio
printed circuit
circuit board
Prior art date
Application number
PCT/AU2013/000929
Other languages
French (fr)
Inventor
Anthony Joseph Boscacci
Patrick J Latter
Original Assignee
Nfa Innovations Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2012903620A external-priority patent/AU2012903620A0/en
Application filed by Nfa Innovations Pty Ltd filed Critical Nfa Innovations Pty Ltd
Publication of WO2014028972A1 publication Critical patent/WO2014028972A1/en

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/16—Anti-collision systems
    • G08G1/161—Decentralised systems, e.g. inter-vehicle communication
    • G08G1/162—Decentralised systems, e.g. inter-vehicle communication event-triggered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L25/00—Recording or indicating positions or identities of vehicles or vehicle trains or setting of track apparatus
    • B61L25/02—Indicating or recording positions or identities of vehicles or vehicle trains
    • B61L25/025—Absolute localisation, e.g. providing geodetic coordinates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L29/00—Safety means for rail/road crossing traffic
    • B61L29/24—Means for warning road traffic that a gate is closed or closing, or that rail traffic is approaching, e.g. for visible or audible warning
    • B61L29/246—Signals or brake- or lighting devices mounted on the road vehicle and controlled from the vehicle train
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/09—Arrangements for giving variable traffic instructions
    • G08G1/0962—Arrangements for giving variable traffic instructions having an indicator mounted inside the vehicle, e.g. giving voice messages
    • G08G1/0965—Arrangements for giving variable traffic instructions having an indicator mounted inside the vehicle, e.g. giving voice messages responding to signals from another vehicle, e.g. emergency vehicle
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/16—Anti-collision systems
    • G08G1/166—Anti-collision systems for active traffic, e.g. moving vehicles, pedestrians, bikes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L2205/00—Communication or navigation systems for railway traffic
    • B61L2205/04—Satellite based navigation systems, e.g. GPS

Definitions

  • the present invention relates to an apparatus for radio break-in and particularly to a distributed network of mobile and fixed radio transceivers and receivers, centred on rail networks and road vehicles.
  • Visual warnings can be obscured by bad weather conditions such as fog or heavy rain or by temporary obstructions (such as a truck parked near signage).
  • Driver behavior plays a major role in the effect of visual warnings. Drivers become complacent and, if they are lucky, only have close calls to remind them of the dangers on the road.
  • Audible warnings such as sirens and horns produced from locations outside of the vehicle, can remain unheard by motorists due to vehicle insulation and loud sound systems.
  • Passive have static warning signs (stop or give way signs) that are visible on approach. This signage is unchanging with no mechanical aspects or light devices.
  • Active in addition to passive railway level crossing signage, these are controlled by automatic warning systems. Including flashing lights, automatic gates (booms, boom gates); audible devices (bells, gongs), advanced warning signs or other warning devices are activated by approaching trains.
  • automatic warning systems Including flashing lights, automatic gates (booms, boom gates); audible devices (bells, gongs), advanced warning signs or other warning devices are activated by approaching trains.
  • the present invention is directed to an apparatus for radio break-in which may at least partially overcome at least 'one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.
  • the present invention in one form, resides broadly in an in-vehicle unit for a radio interruption system, the unit adapted to be connected between an existing vehicle stereo head unit and vehicle's speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a signal, an internal transmitter for transmitting a signal, at least a pair of audio switching relays, a first switching relay to switch both positive and negative speaker outputs between the vehicle head unit and a first set of vehicle speakers and a second switching relay to switch only positive speaker outputs between closed and open for the vehicle head unit and a second set of vehicle speakers, and at least one processor peripheral interface wherein when the unit receives a warning message, the processor interrupts a normal signal from the existing vehicle stereo head unit to all of the vehicle speakers, and directs the warning message to the first set of vehicle speakers.
  • the present invention resides in a multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly or implements instructions based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly, based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
  • the present invention resides in an on board unit for a moving vehicle, the on-board unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
  • the present invention resides in a road side unit for use with fixed transport infrastructure, the road side unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to actuate a change in the fixed transport infrastructure based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
  • the present invention resides in a radio break-in apparatus including an in- vehicle unit associated with a member vehicle in a first category, the in vehicle unit adapted to be connected between an existing vehicle stereo head unit and vehicle speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a radio break-in signal, an internal transmitter for transmitting a signal, and at least one processor peripheral interface, an on-board unit associated with a member vehicle in a second category, the on-board unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second
  • the present invention resides in a radio break-in apparatus including an in-vehicle unit associated with a member vehicle in a first category, the in vehicle unit adapted to be connected between an existing vehicle stereo head unit and vehicle speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a radio break-in signal, an internal transmitter for transmitting a signal, and at least one processor peripheral interface, an on-board unit associated with a member vehicle in a second category, the on-board unit including at least one
  • multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly wherein when a member vehicle in a second category approaches a piece of fixed transport infrastructure, the onboard unit broadcasts a radio break-in transmission, which when received by an in-vehicle unit of a member vehicle of the first category, the processor interrupts a normal signal from the existing vehicle stereo head unit to the vehicle speakers, and issues a warning message to vehicle speakers.
  • a radio break-in transmission can be issued to a member vehicle of the first category from active infrastructure or from an on-board unit in a directed manner, and/or from the active infrastructure or on-board unit as a broadcast radio break-in transmission.
  • the GPS receiver and transceiver of the member vehicle of the second category will typically be associated with a computer processor.
  • the processor will typically be preloaded or have access to the location information of all infrastructure within the system, whether fixed infrastructure or mobile infrastructure and/or member vehicles of the second category including itself.
  • Updating of the relative positions of infrastructure and/or member vehicles within the system will preferably be via a real time link such that the positions of infrastructure and/or member vehicles are represented in real time.
  • the processor will typically register or calculate the position of member vehicles relative to each other and/or other elements of infrastructure, in particular fixed infrastructure where changes in mode of operation are required or mobile infrastructure where collision avoidance is required.
  • Examples of fixed infrastructure within the system include fixed transport infrastructure such as controlling lights, intersections, level crossings, and other points of interest such as buildings or hospitals.
  • Examples of mobile infrastructure include other member vehicles and other moving obstacles which may not be members of the system.
  • the on-board unit will issue a radio transmission to transport infrastructure dependent upon proximity of an approaching member vehicle.
  • the locating device on each member vehicle maintains a position of the member vehicle and an on board unit is preferably configured to calculate distance, approach velocity and time of a member vehicle of the second category to any transport infrastructure, and transmit a signal once the member vehicle crosses a point at a predetermined time from the transport infrastructure.
  • the transceiver will transmit a radio transmission in one or both of a broadcast and a directed manner.
  • the signal will typically be directed at the transport infrastructure to trigger a response from the infrastructure which may be in the form of a return signal or an action, preferably a change of mode of operation of the transport infrastructure.
  • the position of all infrastructure pieces, whether fixed or mobile infrastructure, will preferably be identified to the locating device.
  • the GRSS system consists of several types of devices:
  • RSU roadside unit
  • IVU An in vehicle unit (IVU) also known as the PIXIE, installed in road vehicles.
  • Each component interacts to the other components of the system through well- defined interfaces, to facilitate future flexibility in the design and implementations of the components themselves.
  • the GRSS system of the present invention is adapted for use on any one or more transport networks including road and rail but is particularly useful in a rail context where the rail intersects with a road network such as at level crossings.
  • Rail level crossings typically have either passive or active control to guide road users. Passive rail level crossings normally have static warning signs [stop or give way signs] that are visible on approach. The signage is typically unchanging with no mechanical aspect or lighting devices.
  • Active rail level crossings typically have the same signage used on passive rail level crossings but also have automatic warning systems including typically flashing lights, automatic gates [booms, or boom gates], portable devices such as bells or sirens, advance warning signs or other warning devices activated by approaching trains.
  • automatic warning systems including typically flashing lights, automatic gates [booms, or boom gates], portable devices such as bells or sirens, advance warning signs or other warning devices activated by approaching trains.
  • the present invention and therefore has three particularly preferred embodiments related to whether a level crossing is passive or active.
  • a level crossing is passive or active.
  • low risk level crossing (these are normally passive level crossings]
  • onboard unit of a rail vehicle is provided with the location of the level crossing and upon approach, broadcasts a radio transmission once within a particular warning distance of the level crossing which can be received by in vehicle units of member vehicles within range.
  • a Type 2 medium risk level crossing (these are normally passive level crossings provided with a roadside unit of the invention] the onboard unit provided onboard a rail vehicle is provided with the location of the level crossing and upon approach, within a particular warning distance, the onboard unit issues a directed radio transmission to the roadside unit in order to ascertain the status of the roadside unit. If the status of the roadside unit is active, the roadside unit confirm this by return transmission to the onboard unit and also transmits a targeted or directed radio transmission to relevant member vehicles. If the roadside unit is not active, no return transmission is issued and the onboard unit issues a broadcast radio transmission which can be received by in vehicle Units of member vehicles within range.
  • a UHF link is preferably used between components of the system. Once a transmission is received by a component, the processor of the component receiving the transmission will normally implement instructions based on the transmission which are stored in the memory of the component.
  • the OBU is an embedded computer system incorporating a UHF transceiver and GPS receiver, which tracks the locomotives location on the rail network and controls the transmission of warning messages to road vehicles, either directly through its local UHF transmitter (Type 1 crossing), or via road-side units (Type 2 and 3 crossings).
  • the on board unit is associated typically with a moving vehicle.
  • the on-board unit includes at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data
  • the communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
  • the OBU has the following purposes: 1. To automatically repetitively estimate the locomotive's position, using GPS, a crossing and waypoint database and locomotive tachometer inputs to determine whether it is approaching any level crossings, and if so, which level crossing. 2. To automatically provide early warning to RSU's at type 2 and 3 crossings, via radio data communications, that the locomotive is approaching.
  • a GPS receiver repetitively estimates the locomotive's location.
  • a distance/speed input (Tachometer) from within the locomotive is used to temporarily support location tracking if the GPS is offline.
  • Each OBU includes at least one and preferably a pair of Multitrax components to control operation of the OBU and to offer redundancy.
  • Each Multitrax component is preferably a multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly or implements instructions based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly, based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
  • Each OBU preferably has a unique address or device identifier, allowing it to be identified within the system.
  • the OBU is preferably associated with a provider of information and/or stores information related to any one or more of the transport networks or vehicles within the system.
  • the provision of information to the OBU may be through a wireless link or a physical device such as a removable data storage device may be used with upload external content to the OBU.
  • the RSU is essentially a multi-band, multi-protocol radio transceiver station which communicates with passing trains, as well as transmitting warning messages directly to road vehicles.
  • Each RSU has a unique address or device ID, allowing it to be identified within the system.
  • a processor within the RSU manipulates data and controls warning message transmissions.
  • Data is entered via a serial connection or GPRS network and stored in a solid state memory device.
  • the solid state memory device can be of a removable type such as an SD Card.
  • Directional antennas are used to direct the UHF transmission of the warning message, an adjustable splitter/attenuator controls the distance of the transmission.
  • Power for the RSU can be supplied either from existing fixed infrastructure (if available) or from a battery source with solar recharge facility.
  • An conventionally available power supply converter which conforms to the relevant rail standards will be used to connect fixed infrastructure power to the RSU power input.
  • Data may be transmitted from the RSU to vehicles via UHF to in vehicle units or via a Dedicated Short Range Communication (DSRC) transceiver.
  • DSRC Dedicated Short Range Communication
  • This data can be used by automotive computers.
  • the DSRC data is not intended to be used as the primary means of notifying vehicle operator of dangerous situations due to the limitations of the current 5.9GHz DSRC system i.e. range and latency.
  • the IVU is a UHF radio receiver that is retrofitted between a vehicle stereo unit and the power/speaker cabling.
  • the IVU When the IVU receives a UHF warning message, it disconnects the signal received from the stereo to the speakers and directs the incoming warning message to the front speakers.
  • the IVU is designed to "fail to safe”. If the power supply to the IVU is not
  • the stereo signal normally routed to the speakers is cut, thus notifying the vehicle operator of a problem.
  • the IVU carries out a self-test by transmitting a small test signal to itself, if it does not confirm it is operating correctly the speakers will remain muted; thus notifying the vehicle's operator of the IVU's failure.
  • the IVU contains an internal linearly-polarised UHF antenna or based on installation, may be connected to an external antenna.
  • the IVU is able to operate from a 12-24VDG supply with a negative chassis only.
  • An example of this would be a motorist approaching a rail level crossing and receiving a message that an ambulance was approaching. Although it is appropriate that the ambulance transmits its warning message, it may temporarily distract the driver and result in minimised attention to the level crossing. Should a train be approaching this level crossing, the warning of the highest priority would be determined that a potential for a collision with the train would take precedence. In this instance, the IVU would be able to make this determination and switch to the higher priority warning. The ambulance would also be notified of the train's presence.
  • a portable calibration unit will be needed to ensure that all components of the GRSS system are calibrated to ensure warning messages are received by IVU's in a timely manner.
  • the PCU is designed to set an OBU and RSU's warning message power based upon physical installation location of the units and an IVU's receive sensitivity based upon in vehicle mounting.
  • a System Control Centre will be required to coordinate data coming in and out of the GRSS system. This data includes updates to the crossing database, faults reported in the system and general operational logs. GRSS system data is sent via GPRS or via UHF, and the System Control Centre will monitor this data for error messages and faults. The System Control Centre will be responsible for keeping locomotive databases up-to-date and providing a means to enter new track information and marker data.
  • the OBU there will be multiple Master and Slave MultiTrax component.
  • the OBU upon power up, identifies which MultiTrax component will be the Master and which will be the Slave.
  • the OBU once powered up, will be able to communicate and update the HMI display.
  • the OBU is able to monitor the health of its systems.
  • Systems that are to be monitored include the GPS module, the memories and data storage and the MultiTrax component itself.
  • the OBU is able to establish if a MultiTrax component has failed.
  • the RSU is able to monitor the health of the data MultiTrax component and the warning message MultiTrax component.
  • the OBU upon monitoring the systems state, reports the system state to the HMI. If the system state has changed to an error state, the system stores this error to a log file. This error should also be transmitted back to the system control centre when able.
  • the OBU has Two (2) MultiTrax component, each with its own GPS.
  • the OBU is to be able to read GPS data provided by the GPS modules.
  • the OBU is supplied a tachometer input from the locomotive.
  • the OBU is to be able to interpret signals coming from the tachometer and convert these to speed and distance readings.
  • the OBU Within the OBU is high capacity memory storage which will contain a crossing database.
  • the crossing database contains a list of every crossing and key marker position providing its GPS latitude and longitude coordinates.
  • the OBU shall be able to search through this database and be able to locate the next key marker position or crossing based on the GPS coordinates provided by the GPS.
  • the OBU through the use of Tachometer input and GPS input, shall be able to track its current speed.
  • the OBU Using the crossing database and the current GPS coordinates of the locomotive, the OBU will be able to calculate the distance and time to the next crossing that it will need to activate.
  • the OBU will be able to activate a local warning message and be able to transmit this over UHF for a provided amount of activation time.
  • the activation time will be related to the amount of time that the locomotive is approaching the crossing and is over the crossing.
  • the OBU will not only be required to activate the local UHF warning message but ensure that it is activated at the correct time before approaching the crossing.
  • a locomotive may perform a number of actions when approaching a crossing. As an example, there may be a station just prior to the level crossing at which the locomotive may become stationary.
  • the OBU shall continue to transmit a warning message whilst it is within a defined distance to the 'crossing. The warning message will only deactivate when the train is beyond the crossing.
  • the OBU will be able to self-assess its' Local UHF transmissions and monitor if they are being transmitted.
  • the OBU when within a defined communication range of an RSU, will establish a connection with an RSU unit to begin activation of its local UHF warning message.
  • a locomotive OBU should be able to establish a communication link with an RSU at a greater distance than 50 seconds from the crossing when the locomotive is moving at 100kph.
  • the OBU shall be able to calculate and transmit a start activation time and activation timeout to the RSU.
  • the OBU shall disconnect from the RSU.
  • the Connection disconnection routine may continue multiple times during the locomotives passing of the level crossing.
  • the OBU shall deactivate its local UHF Warning Message.
  • the OBU shall monitor that the RSU has deactivated its Local Warning Message.
  • the OBU will be required to monitor and activate multiple crossings.
  • OBU activates Local UHF Warning Message on the same channel frequency until clear of both Type 1 Crossings.
  • Type 2 Crossing if in communication range, is sent an Activation message. OBU waits for acknowledgement timeout. OBU activates Local Warning Message for Type 1 Crossing for Warning Message Time. OBU again communicates with Type 2 crossing at completion of local Warning Message and waits a defined acknowledgment timeout (less than 1 second). The process is repeated until clear of crossing.
  • OBU sequentially connects and disconnects from each Type 2 crossing, updating the Activation Timeout time.
  • the OBU shall incorporate within its UHF communication protocol a Carrier Sense Multiple Access/Collision Avoidance algorithm.
  • the OBU shall first monitor the channel activity before proceeding with a Data Transmission.
  • the RSU contains two MultiTrax, one which will be used for data transmission and one which will be used for UHF Warning Message transmission.
  • the RSU will select the role of warning message transmission by its configuration data.
  • the Warning Message MultiTrax may be connected to an Attenuator Splitter board.
  • the RSU shall only activate a warning message system when it has been told to do so by an OBU or another RSU.
  • the RSU is not to provide false activations.
  • the RSU shall only activate when its Start Activation Timeout has expired. RSU activation shall not occur until this time. .
  • the RSU shall be able to monitor its UHF Warning Message power being transmitted and determine if a transmission has occurred.
  • the RSU will only de-activate its warning message when the activation timeout reaches zero.
  • the RSU shall be able to transmit a warning message in a desired direction and distance.
  • the RSU shall be able to minimise nuisance activations of Pixie In- Vehicle Units where activation is not required.
  • the RSU shall be able to communicate to multiple OBU units by being able to connect and disconnect from each OBU. Activation times for the RSU will take the worst case scenario (earliest activation time start and latest activation time end)
  • the RSU for Type 3 Level Crossings, is connected to railway infrastructure.
  • the RSU when required, is to be'activated by the trackside infrastructure.
  • the RSU has the capability of controlling trackside infrastructure if required.
  • the RSU shall incorporate a Carrier Sense Multiple Access/Collision Avoidance algorithm.
  • the RSU shall first monitor the channel activity before proceeding with a Data Transmission.
  • the IVU shall switch the in road vehicle speakers back to the road vehicles head unit signal rather than the UHF Warning Message signal.
  • the IVU after receiving a UHF Warning Message, shall only perform 3 cycles of the Warning Message before switching back to the road vehicles head unit to limit the annoyance factor.
  • the IVU based on a Warning Message Priority System, shall activate the warning message of highest priority.
  • the Warning Message must finalise its playback before a higher priority message is played.
  • Slave OK - OBU upon detecting a failed GPS Signal shall request Valid GPS Data from Slave Unit.
  • ⁇ Failed To Receive GPS Signal On Master and Slave Unit - OBU provides warning output on HMI that GPS has failed. Locomotive will track progress via Tacho input only.
  • OBU ⁇ Failed To Receive Tacho Signal on Master and Slave - OBU shall revert back to GPS only coordinates. OBU provides HMI with warning the Tacho has failed. Error is logged.
  • ⁇ Failed To Receive GPS and Tacho Signal on Master and Slave - OBU shall provide warning message to HMI that GPS and Tacho have failed.
  • the OBU will, if both databases are corrupted, send a warning message to the HMI and log the fault. The OBU will then move to the next location in the database.
  • the OBU whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason.
  • the OBU must recognise a warning message signal is not being transmitted and must activate the redundant MultiTrax.
  • the OBU shall activate its Type 1 Local UHF Warning Message.
  • the Local UHF Warning Message shall be transmitted on a different frequency to that of the RSU Warning Message to ensure that, if Type 2/3 activation has occurred, the locomotive will not interfere with the RSU Warning Message.
  • RSU Failure Modes including: • Master Failed, Slave OK - Upon RSU Master MultiTrax unit failing, the RSU is considered to have failed. OBU will log the RSU fault.
  • OBU will log the RSU fault.
  • the RSU whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason.
  • the RSU must recognise a warning message signal is not being transmitted and must log the fault.
  • the IVU will fail to safe when an electronic or mechanical failure occurs. If the IVU fails, the radio front speakers will fail which will bring the failure to the attention of the vehicle driver.
  • the present invention may also include a Personal Device Unit (PDU).
  • PDU Personal Device Unit
  • the PDU is a UHF radio receiver which can be integrated into earphone sets or directly into personal devices such as smartphones, mobile phones, tablets, MP3 players and the like or retrofit to such devices which include one or more speakers. This is particularly useful for use in pedestrian circumstances where pedestrians are placed in high risk areas such as pedestrian level crossings.
  • the PDU when the PDU receives a warning message, it switches off the signal from the master unit to the speakers of the one or more speakers of the personal devices, and directs the incoming message to the speaker(s) of the personal device or via the headphones.
  • the PDU also has the ability to receive data messages via UHF, which it passes on to the personal device's internal computer via a preferred serial cable connection.
  • the mobile device's speakers are muted, thus notifying the user of a problem.
  • the system in the mobile device could be configured to use power directly from the personal device's battery, so operation could not be interfered with by the user. This is particularly useful when applied to young users as it would work if the device was turned off deliberately through a low state of charge.
  • the PDU preferably carries out a self-test by transmitting a small test signal to itself. If the PDU does not confirm that it is operating correctly, the speakers of the personal device will remain muted; thus notifying the user of the PDU's failure.
  • Figure 1 is a schematic view of a particularly preferred embodiment of the invention applied to a type 1 , low risk - passive level crossing.
  • Figure 2 is a schematic view of a particularly preferred embodiment of the invention applied to a type 2, medium risk - passive crossing.
  • Figure 3 is a schematic view of a particularly preferred embodiment of the invention applied to a type 3, high risk - active crossing.
  • Figure 4 is . a schematic view of a preferred embodiment of the system of the present invention and the communications interfaces between the different components of the system.
  • Figure 5 is a pictorial representation of an on board unit human interface according to a preferred embodiment of the present invention.
  • Figure 6 is a schematic view of the internal components and external interfaces of a Multitrax component according to a particularly preferred embodiment of the present invention.
  • Figure 7 is a schematic view of the UHF transceiver of the preferred embodiment contained within the Multitrax component of the preferred embodiment.
  • Figure 8 is a schematic illustration showing the location of the in vehicle unit in relation to the vehicle stereo, speakers and power supply according to a preferred embodiment.
  • Figure 9 is a schematic illustration of the internal components of the in vehicle unit according to a preferred embodiment.
  • FIG. 10 is a flowchart illustrating the power-on self-test (POST) for the in vehicle unit according to a preferred embodiment of the invention.
  • POST power-on self-test
  • Figure 1 1 is a flowchart illustrating the operation of the IVU in idle/scanning mode according to a preferred embodiment of the invention.
  • Figure 12 is a flowchart illustrating the operation of the IVU in receiving signal mode for the in vehicle unit according to a preferred embodiment of the invention.
  • Figure 13 is a flowchart illustrating the operation of the IVU in calibrating mode for the in vehicle unit according to a preferred embodiment of the invention.
  • Figure 14 is an illustration of the hierarchical structure of the software operating on the IVU with arrows indicating the direction of function calling according to a preferred embodiment.
  • Figure 15 is a schematic illustration of the IVU communications baseband spectrum according to a preferred embodiment.
  • Figure 16 is a schematic illustration of the IVU communications baseband spectrum for an FSK data transmission according to a preferred embodiment.
  • Figure 17 is a schematic illustration of the IVU transmission sequence (not to scale) according to a preferred embodiment.
  • Figure 18 is a schematic illustration of the IVU transmission sequence for a repeated message (not to scale) according to a preferred embodiment.
  • Figure 19 is a schematic illustration of the IVU calibration transmission sequence (not to scale) according to a preferred embodiment.
  • Figure 20 is a schematic illustration of the IVU transmission sequence for FSK data transmission (not to scale) according to a preferred embodiment.
  • Figure 21 is a schematic illustration of the preferred radiation coverage of adjacent roads provided by RSU antennas at type 2 and 3 crossings according to a preferred embodiment.
  • Figure 22 is a schematic illustration of the preferred radiation coverage of adjacent roads provided by RSU antennas at type 2 and 3 crossings where more than two antenna's are required according to a preferred embodiment.
  • Figure 23 is a schematic illustration of the preferred radiation coverage of adjacent roads provided by OBU antennas at type 1 crossings according to a preferred embodiment.
  • Figure 24 is a schematic illustration of the preferred OBU transmission power calculation according to a preferred embodiment.
  • a radio break in system which incorporates a variety of individual apparatus operating together to form an integrated system.
  • Figures 1 to 3 are pictorial representations of the railway crossings in relation to which the present invention is used.
  • the crossings have been categorised into three types:
  • a battery/mains powered trackside transmitter is controlled/activated by the approaching locomotives On-board GPS system.
  • Directional antennas ensure that messages are transmitted to relevant vehicles only; minimising the nuisance aspect.
  • the controller checks to see that the transmitter is activating appropriately, and fails to safe by activating the train's transmitter in the event of a malfunction as per protections offered in type 1 system.
  • Trackside transmitter is controlled by the existing active infrastructure.
  • Directional antennas ensure that messages are transmitted to relevant vehicles only minimising the nuisance aspect.
  • On board Controller monitors the operational status of the active crossing's warning system, and fails to safe by activating the train's transmitter in the event of a malfunction as per protections offered in type 1 system.
  • the system of the present invention utilises a UHF data link from train to fixed infrastructure.
  • a UHF audio transmission is sent from either the train or fixed infrastructure to the road vehicle's In Vehicle Unit.
  • the apparatus of the present invention is a distributed network of mobile and fixed radio transceivers and receivers, centred on rail networks and road vehicles.
  • the system includes of a GPS control system on board the locomotive.
  • the system activates a verbal warning message either directly to vehicles or to vehicles via the road crossing infrastructure.
  • the warning message is transmitted directly to the vehicles' existing stereo speaker system, regardless of the stereo's status; radio, on, off, CD, hands free Bluetooth etc.
  • the warning message is transmitted directly to the vehicles' existing stereo speaker system, regardless of the stereo's status; radio, on, off, CD, hands free Bluetooth etc.
  • FIG. 4 Illustrated in Figure 4 is a system communications overview diagram.
  • the GRSS system consists of several types of devices:
  • RSU roadside unit
  • IVU in vehicle unit
  • Each component interacts to the other components of the system through well-defined interfaces, to facilitate future flexibility in the design and implementations of the components themselves. These interfaces are illustrated in Figure 4 and are described in more detail below.
  • the OBU is an embedded computer system incorporating a UHF transceiver and GPS receiver, which tracks the locomotive's location on the rail network and controls the transmission of warning messages to road vehicles, either directly through its local UHF transmitter (Type 1 crossing), or via road-side units (Type 2 and 3 crossings).
  • Two cooperative microprocessors within the OBU control its operation offering redundancy in the event of hardware failure; both are contained within a specific portion of the OBU described below.
  • the microprocessors within the OBU track the locomotives location, analyse future crossings, manipulate data, provide data transmission to RSU's and control warning message transmissions.
  • the OBU unit has dual power supplies, processors, GPS modules & antennas, GPRS modules & Antennas, UHF transceivers & Antennas in the event of a localised hardware failure.
  • Each OBU has a unique address or device ID, allowing it to be identified within the system.
  • Configuration data and track databases are entered via a serial connection or GPRS network and stored in a solid state memory device.
  • Data may be loaded directly onto large memory device at manufacture time).
  • the solid state memory device is of a removable storage type so that databases may be uploaded external to the unit.
  • Data which is uploaded to the OBU from GPRS or serially,, and stored, includes:
  • Power for the OBU is supplied from the locomotive, via twin rail certified supplies to reduce the risk of power failure.
  • a human interface (HMI) to the OBU is achieved by the use of an LCD touch-screen display and/or audio speaker and/or indication LED's.
  • the OBU of the preferred embodiment includes: 1. 1 x HMI LCD Screen (Optional)
  • An OBU is installed in each locomotive in the rail network in which the GRSS is being used.
  • the unit may be enclosed in one or more physical enclosures - e.g. the HMI user interface may be separate from the OBU and power supply units, to minimise clutter in the locomotive cabin.
  • the UHF, GPRS and GPS antennas are all to be mounted externally on the locomotive, in a location such as the cabin's rooftop.
  • the power supply units convert electrical power from the locomotive to a form suitable for use by the rest of the OBU system.
  • the power supply used must be suitable for rail operation and shall output 12V/24V DC @ 5A/2.5A continuous power to supply the rest of the OBU's components.
  • the power supply must conform to the relevant rail standards. As the voltage and frequency standards for electrical power on locomotives varies widely, power supply units will be selected as required.
  • the RSU (mains powered) of the preferred embodiment includes: 1. 2 x MultiTrax component
  • the RSU (solar powered) of the preferred embodiment includes: 1. 2 x MultiTrax component
  • the IVU is a UHF radio receiver that is retrofitted between a vehicle stereo unit and the power/speaker cabling.
  • the IVU When the IVU receives a UHF warning message, it disconnects the signal received from the stereo to the speakers and directs the incoming warning message to the front speakers.
  • the IVU is designed to "fail to safe”. If the power supply to the IVU is
  • the stereo signal normally routed to the speakers is cut, thus notifying the vehicle operator of a problem.
  • the IVU contains an internal linearly-polarised UHF antenna or based on installation, may be connected to an external antenna.
  • the IVU is able to operate from a 12-24VDC supply with a negative chassis only.
  • a portable calibration unit will be needed to ensure that all components of the GRSS system are calibrated to ensure warning messages are received by IVU's in a timely manner.
  • the PCU is designed to set an OBU and RSU's warning message power based upon physical installation location of the units and an IVU's receive sensitivity based upon in vehicle mounting.
  • a System Control Centre will be required to coordinate data coming in and out of the GRSS system. This data includes updates to the crossing database, faults reported in the system and general operational logs. GRSS system data is sent via GPRS or via UHF, and the System Control Centre will monitor this data for error messages and faults. The System Control Centre will be responsible for keeping locomotive databases up-to-date and providing a means to enter new track information and marker data.
  • the application may be required for a "Mesh Network" of RSU's to be utilised for the transmission of data throughout the GRSS system and for the mass synchronisation of warning messages, for example during emergency situations such as bush fires, storms etc.
  • a "Mesh Network" of RSU's may be utilised for the transmission of data throughout the GRSS system and for the mass synchronisation of warning messages, for example during emergency situations such as bush fires, storms etc.
  • OBU's and RSU's may communicate together, two RSU's may communicate data.
  • Mesh Networked communication may be necessary for locations where the GSM network may not be available or as a redundancy to the GSM network.
  • This one-way radio communications interface is an audio FM signal employing a continuous tone-coded squelch system (CTCSS).
  • CTCSS ensures that the IVU receiver only relays audio from the GRSS system, instead of relaying all signals received on its frequency.
  • the carrier frequency may be from 400MHz to 470MHz.
  • the modulating signal is literally a human-perceivable (e.g. voice and/or siren sounds) audio signal in addition to the sub-audio CTCSS signal.
  • This interface is described in detail in the "Pixie IVU Communications Specification" document. The IVU only receives communications in this interface, it does not transmit.
  • This bidirectional digital communications protocol is carried over the TCP/IP protocol via GPRS and is primarily used for updating the rail network crossings maps within each OBU, as well as notifying the system control centre of system failures.
  • This bidirectional digital communications protocol operates over a direct serial link between a PC and an OBU/RSU, and is primarily used as an initial or alternative method to update rail network crossings maps within the OBU and configuration data in the OBU and RSU.
  • GPS is repetitively used by each OBU as the primary means to ascertain its position within the rail network.
  • a GPRS network and the internet will be used to carry data communications between a control centre and OBU's and RSU's.
  • a GPRS interface is employed within both the RSU and OBU with a higher-level protocol used to communicate between central control and each OBU and RSU.
  • An electrical signal from either a dedicated speed/distance sensor within the locomotive's mechanical system, or the locomotive's control system is provided to the OBU.
  • the IVU can switch off up to 6 speakers channels, 2 of which (front speakers) can relay warning audio signals.
  • the IVU is able to tolerate minimum speaker impedances of 3.5 Ohms. Switches are able to pass up to 250V RMS (with respect to chassis) and 5A of current when not interrupting the normal speaker circuits.
  • 250V RMS with respect to chassis
  • 5A of current when not interrupting the normal speaker circuits.
  • Front speakers must be rated to 10W RMS.
  • the IVU can be powered from a 12V-24V DC supply with a negative chassis. As the IVU draws non-negligible current, it is advised that it is wired to only be supplied with power when the vehicle is occupied (e.g. when ignition key in "accessories” position), to prevent draining of batteries. During operation, the IVU may draw a maximum of 5A of current, and so should be fused appropriately.
  • the RSU is capable of switching up to 1 OA and 250 VAC, on 8 external relays to provide control of warning signals such as flashing lights and alarms.
  • the RSU has 8 Digital outputs, 8 Digital Inputs, 2 Analogue Inputs, 2 Analogue Outputs, Audio output as well as a serial interface (RS485) to allow remote control and monitoring of existing crossing infrastructure.
  • Mains-powered RSU's require a 12VDC 3 Amp power input, which is required to be 99% uninterrupted, as undesirable backup provisions exist such as direct train to IVU transmission.
  • the OBU there will be multiple Master and Slave MultiTrax component.
  • the OBU upon power up, identifies which MultiTrax component will be the Master and which will be the Slave.
  • the OBU once powered up, will be able to communicate and update the HMI display.
  • the OBU is able to monitor the health of its systems.
  • Systems that are to be monitored include the GPS module, the memories and data storage and the MultiTrax component itself.
  • the OBU is able to establish if a MultiTrax component has failed.
  • the RSU is able to monitor the health of the data MultiTrax component and the warning message MultiTrax component.
  • the OBU upon monitoring the systems state, reports the system state to the HMI. If the system state has changed to an error state, the system stores this error to a log file. This error should also be transmitted back to the system control centre when able.
  • the OBU has Two (2) MultiTrax components, each with its own GPS. The OBU is to be able to read GPS data provided by the GPS modules.
  • the OBU is supplied a tachometer input from the locomotive.
  • the OBU is to be able to interpret signals coming from the tachometer and convert these to speed and distance readings.
  • the OBU Within the OBU is high capacity memory storage which will contain a crossing database.
  • the crossing database contains a list of every crossing and key marker position providing its GPS latitude and longitude coordinates.
  • the OBU shall be able to search through this database and be able to locate the next key marker position or crossing based on the GPS coordinates provided by the GPS.
  • the OBU through the use of Tachometer input and GPS input, shall be able to track its current speed.
  • the OBU Using the crossing database and the current GPS coordinates of the locomotive, the OBU will be able to calculate the distance and time to the next crossing that it will need to activate.
  • the OBU will be able to activate a local warning message and be able to transmit this over UHF for a provided amount of activation time.
  • the activation time will be related to the amount of time that the locomotive is approaching the crossing and is over the crossing.
  • the OBU will not only be required to activate the local UHF warning message but ensure that it is activated at the correct time before approaching the crossing.
  • a locomotive may perform a number of actions when approaching a crossing. As an example, there may be a station just prior to the level crossing at which the locomotive may become stationary.
  • the OBU shall continue to transmit a warning message whilst it is within a defined distance to the crossing. The warning message will only deactivate when the train is beyond the crossing.
  • the OBU will be able to self-assess its' Local UHF transmissions and monitor if they are being transmitted.
  • the OBU when within a defined communication range of an RSU, will establish a connection with an RSU unit to begin activation of its local UHF warning message.
  • a locomotive OBU should be able to establish a communication link with an RSU at a greater distance than 50 seconds from the crossing when the locomotive is moving at 100kph.
  • the OBU shall be able to calculate and transmit a start activation time and activation timeout to the RSU.
  • the OBU shall deactivate its local UHF Warning Message.
  • the OBU shall monitor that the RSU has deactivated its Local Warning Message.
  • the OBU will be required to monitor and activate multiple crossings.
  • OBU activates Local UHF Warning Message on the same channel frequency until clear of both Type 1 Crossings.
  • Type 2 Crossing if in communication range, is sent an Activation message. OBU waits for acknowledgement timeout. OBU activates Local Warning Message for Type 1 Crossing for Warning Message Time. OBU again communicates with Type 2 crossing at completion of local Warning Message and waits a defined acknowledgment timeout (less than 1 second). The process is repeated until clear of crossing.
  • OBU sequentially connects and disconnects from each Type 2 crossing, updating the Activation Timeout time.
  • the OBU shall incorporate within its UHF communication protocol a Carrier Sense Multiple Access/Collision Avoidance algorithm.
  • the OBU shall first monitor the channel activity before proceeding with a Data Transmission.
  • the RSU contains two MultiTrax components, one which will be used for data transmission and one which will be used for UHF Warning Message transmission.
  • the RSU will select the role of warning message transmission by its configuration data.
  • the Warning Message MultiTrax component may be connected to an Attenuator Splitter board.
  • the RSU shall only activate a warning message system when it has been told to do so by an OBU or another RSU. The RSU is not to provide false activations.
  • the RSU shall only activate when its Start Activation Timeout has expired. RSU activation shall not occur until this time.
  • the RSU shall be able to monitor its UHF Warning Message power being transmitted and determine if a transmission has occurred.
  • the RSU will only de-activate its warning message when the activation timeout reaches zero.
  • the RSU shall be able to transmit a warning message in a desired direction and distance.
  • the RSU shall be able to minimise nuisance activations of In- Vehicle Units where activation is not required.
  • the RSU shall be able to communicate to multiple OBU units by being able to connect and disconnect from each OBU. Activation times for the RSU will take the worst case scenario (earliest activation time start and latest activation time end).
  • the RSU for Type 3 Level Crossings, is connected to railway infrastructure.
  • the RSU when required, is to be activated by the trackside infrastructure.
  • the RSU has the capability of controlling trackside infrastructure if required.
  • the RSU shall incorporate a Carrier Sense Multiple Access/Collision Avoidance algorithm.
  • the RSU shall first monitor the channel activity before proceeding with a Data Transmission.
  • the IVU shall switch the in road vehicle speakers back to the road vehicles head unit signal rather than the UHF Warning Message signal.
  • the IVU after receiving a UHF Warning Message, shall only perform 3 cycles of the Warning Message before switching back to the road vehicles head unit to limit the annoyance factor.
  • the IVU based on a Warning Message Priority System, shall activate the warning message of highest priority.
  • the Warning Message must finalise its playback before a higher priority message is played.
  • Slave OK - OBU upon detecting a failed GPS Signal shall request Valid GPS Data from Slave Unit.
  • ⁇ Failed To Receive GPS Signal On Master and Slave Unit - OBU provides warning output on HMI that GPS has failed ⁇ Locomotive will track progress via Tacho input only.
  • OBU ⁇ Failed To Receive Tacho Signal on Master and Slave - OBU shall revert back to GPS only coordinates. OBU provides HMI with warning the Tacho has failed. Error is logged.
  • ⁇ Failed To Receive GPS and Tacho Signal on Master and Slave - OBU shall provide warning message to HMI that GPS and Tacho have failed.
  • the OBU will, if both databases are corrupted, send a warning message to the HMI and log the fault. The OBU will then move to the next location in the database.
  • the OBU whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason.
  • the OBU must recognise a warning message signal is not being transmitted and must activate the redundant MultiTrax component.
  • the OBU shall activate its Type 1 Local UHF Warning Message.
  • the Local UHF Warning Message shall be transmitted on a different frequency to that of the RSU Warning Message to ensure that, if Type 2/3 activation has occurred, the locomotive will not interfere with the RSU Warning Message.
  • the RSU is considered failed and will not be able to communicate to an OBU.
  • OBU will log the RSU fault.
  • the RSU whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason.
  • the RSU must recognise a warning message signal is not being transmitted and must log the fault.
  • the IVU will fail to safe when an electronic or mechanical failure occurs. If the IVU fails, the radio front speakers will fail which will bring the failure to the attention of the vehicle driver.
  • Sequence of events 1. A train approaches a defined level crossing.
  • OBU on train receives GPS signals and determines that it is within time x of entering a level crossing.
  • OBU begins transmitting warning audio-modulated UHF signal.
  • OBU detects that it is transmitting warning signal OK and continues transmission of signal.
  • IVU in passing road vehicle receives Pixie signal and relays audio warning message to speakers.
  • OBU receives GPS signals and determines that it has finished crossing the road.
  • OBU stops transmission of the warning message.
  • a train approaches a defined level crossing.
  • OBU on train receives GPS signals and determines that it is within time x of entering a level crossing.
  • OBU connects to RSU via frequency and ID data stored in the crossings database located on the OBU.
  • OBU sends warning command to RSU with timeout long enough to allow it to cross the road at its current speed.
  • RSU begins transmitting warning audio-modulated (IVU) UHF signal.
  • IVU warning audio-modulated
  • RSU detects that it is transmitting warning signal OK.
  • RSU responds to OBU that it is transmitting IVU signal OK. OBU disconnects from RSU. 9. IVU in passing road vehicle receives signal and relays audio warning message to speakers. 10. Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
  • a train approaches a defined level crossing.
  • OBU on train receives GPS signals and determines that it is within time x of crossing. 3. OBU connects to RSU via frequency and ID data stored in the crossings database located on the OBU.
  • OBU sends warn command to RSU with timeout long enough to allow it to cross the road at its current speed.
  • RSU begins transmitting warning audio-modulated UHF signal.
  • RSU detects that it is transmitting warning signal OK.
  • RSU switches-on traditional signals installed (e.g. boom gates, flashing lights, bells). 9. RSU responds to OBU that it is transmitting signal OK.
  • IVU in passing road vehicle receives signal and relays audio warning message to speakers.
  • 1 Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
  • a train approaches a defined level crossing.
  • OBU on train receives GPS signals and determines that it is within time x of crossing. 3. OBU attempts to connect to RSU via frequency and ID data stored in the crossings database located on the OBU.
  • OBU verifies that it is transmitting radio data signal using redundant MultiTrax component and UHF antenna. 5. OBU fails to receive acknowledgement from RSU within timeout period.
  • OBU stores failure notification in solid state memory to pass on to control centre when within GPRS range.
  • OBU begins transmitting warning audio-modulated UHF signal.
  • OBU detects that it is transmitting warning signal OK.
  • IVU in passing road vehicle receives signal and relays audio warning message to speakers. 10.
  • Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
  • OBU receives GPS signals and determines that it has finished crossing the road.
  • OBU connects to control centre via GPRS.
  • OBU notifies control centre of crossing failure.
  • a train approaches a defined level crossing.
  • OBU on train receives GPS signals and determines that it is within time x of crossing. 3. OBU connects to RSU via frequency and ID data stored in the crossings database located on the OBU.
  • OBU sends warn command to RSU with timeout long enough to allow it to cross the road at its current speed.
  • RSU begins transmitting warning audio-modulated UHF signal.
  • RSU fails to detect that it is transmitting warning signal.
  • RSU connects to control centre via GPRS if available, and notifies control centre of RSU failure.
  • OBU stores failure notification in solid state memory to pass on to control centre when within GPRS range.
  • OBU begins transmitting warning audio-modulated UHF signal.
  • OBU detects that it is transmitting warning signal OK.
  • IVU in passing road vehicle receives warning signal and relays audio warning message to speakers.
  • OBU receives GPS signals and determines that it has finished crossing the road.
  • OBU connects to control centre via GPRS.
  • OBU notifies control centre of crossing failure.
  • a train approaches a defined level crossing.
  • OBU on train receives GPS signals and determines that it is within time x of crossing. 3. OBU begins transmitting warning audio-modulated UHF signal.
  • OBU fails to detect that it is transmitting warning signal.
  • OBU notifies train driver with audible warning beeps and flashing red failure indicators in the OBU user interface, of the system failing and that a crossing is ahead.
  • the OBU is in range of GPRS it transmits a failure notification to the control centre.
  • the Primary MultiTrax component inside the OBU fails to respond.
  • the redundant MultiTrax component receives no messages from the failed unit, or messages report fault of unit.
  • Redundant MultiTrax component switches control to itself for all OBU tasks.
  • Redundant MultiTrax component reports fault to locomotive operator and logs fault to solid state memory.
  • OBU unit transmits fault via GPRS to control centre which logs the fault.
  • Redundant MultiTrax component issues a reboot command to Primary MultiTrax component to attempt revival of operation.
  • a central component in at least some of the system units identified at paragraph 0107 is the MultiTrax component.
  • the MultiTrax component is essentially a multi-purpose printed circuit board assembly (PCBA) containing a highly-capable microcontroller, solid state data storage and an array of wireless and cable data and audio communications, and general purpose digital and analogue I/O interfaces.
  • PCBA printed circuit board assembly
  • Atmel AT32UC3A0256 AVR32-based microcontroller with a 32-bit core, 256KB of flash, and 64KB of RAM.
  • GPRS transceiver based on a Telit UC864-G GPRS transceiver module. SIM card holder. SMB antenna connector.
  • the MultiTrax component contains a diverse range of internal components, including a high-performance microcontroller and various RF transceivers, one configuration of which is illustrated in Figure 6.
  • This current preferred embodiment of the MultiTrax component contains an Atmel AT32UC3 A0256- ALUT AVR32-based microcontroller.
  • This microcontroller's capabilities include a 32-bit core, 256KB of flash, 64KB of RAM, USB, Ethernet, 7-channel 16-bit PWM, 8- channel 10-bit ADC, 3 -channel timer/counter with 6 PWM/wave outputs, 4 USARTs, 2 SPI buses, and 109 GPIOs.
  • Future versions of the MultiTrax component may contain an ARM-based or XMEGA-based microcontroller.
  • Programming of the microcontroller can be done via two methods: 1. Direct programming through JTAG interface through header Jl .
  • the MultiTrax component will include a real-time clock (RTC) which may only keep time while the unit is externally powered.
  • RTC real-time clock
  • This RTC may be synchronised in software to external time sources, such as GPS, or through any one of the MultiTrax component various
  • the microcontroller uses an external 12MHz crystal, from which it generates its internal clock signals. This is required for the microcontroller's USB interface, as well as providing accurate timing for various applications.
  • the PCB is designed for two digital audio storage and playback options, which can be selected by populating the relevant components:
  • This digital audio option includes 2-channels of audio output from the
  • microcontroller's bitstream audio DAC via simple lst-order low-pass filters.
  • One of these channels (left) is connected to the analogue input of the UHF transceiver, as well as the left channel of the external audio output connector.
  • the other channel (right) is connected to the right channel of the external audio output connector.
  • a Nuvoton Chipcorder ISD 15102 digital audio recording and playback IC is connected to the microcontroller via SPI for data and control. This IC is capable of recording, storing, and playing-back up to 2 minutes of digital audio. Digital audio is readable and writable through the SPI interface using an uncompressed 16- ⁇ bit PCM format. Its single analogue output is connected to the UHF transceiver via its analogue input pin, as well as connecting to the audio output connector left channel. There is no right-hand channel in this option. The lCs single analogue input is connected to the UHF transceiver analogue output pin, as well as connecting to the audio input connector left pin.
  • This IC if installed, also provides general purpose I/O pins which are used for external LCD display interfacing and reading of 2 DIP switch states (see Table 3). 0D links are used to connect these peripherals directly to the microcontroller's GPIO pins to which this IC is normally connected, if this IC is not present.
  • the MultiTrax contains a UHF transceiver - for frequency shift keying (FSK) data and analogue audio communications.
  • FSK frequency shift keying
  • the transceiver has a carrier frequency range of 400MHz to 500MHz (currently), and contains a CML microcircuits CMX881 baseband processing IC, which is able to generate and process CTCSS and DCS squelch schemes, as well as FSK data encoding and decoding.
  • CMX881 baseband processing IC which is able to generate and process CTCSS and DCS squelch schemes, as well as FSK data encoding and decoding.
  • Transmission power is monitored and controlled using the microcontroller via ADC and PWM respectively, and is up to 5W.
  • the UHF transceiver has a female SMB connector for connecting an external antenna.
  • This transceiver has as an input the analogue output of the digital audio storage and playback solution discussed in section 2.3, mixed with an auxiliary audio input connector.
  • the transceiver also has as output a microcontroller ADC input, and an auxiliary audio output connector.
  • This transceiver is connected directly to the microcontroller's SPI bus to input and output data.
  • the MultiTrax contains a Fastrax IT500 GPS receiver module (U1200). This module has an update rate of l OHz.
  • the GPS receiver communicates with the microcontroller via the NMEA protocol using a CMOS-level serial link at 9600bps. This component is interfaced to others as in Table 6.
  • the MultiTrax component contains a Telit UC864-G GPRS transceiver module. This module forms a complete GPRS transceiver, able to operate on 850, 900, 1800 and 1900MHz bands. This module connects to a SIM card holder in which the network's required SIM card will be installed. This component is interfaced to others as in Table 7. This module includes a 50 ⁇ Murata GSC antenna connector. This is linked via a GSC cable to a UFL connector mounted on the MultiTrax PCB.
  • the MultiTrax component contains a DP83848I physical layer Ethernet transceiver, which is connected directly to the microcontroller via Media-independent interface (Mil).
  • Mc Media-independent interface
  • a Maxim MAX-3241 device is used to convert voltage levels from the RS-232 standard to the microcontroller USART0 interface level (3.3V).
  • a RS-485 physical-layer Intersil ISL83086 IC is used to interface the external RS- 485 connector to the microcontroller.
  • microcontroller SPIO internal SPI bus
  • the MultiTrax component contains an LED which may be switched on/off via microcontroller GPIO 109 pin.
  • the MultiTrax component is a general purpose radio communications and I/O module.
  • the PCB is designed to act either as a main board or a plug-in module, depending on the type of connectors for which it is populated.
  • Each connector has allowances to act as either a top-facing stand-alone connector, or a downward-facing set of pins if the board is to act as a plug-in module.
  • the Multitrack component has two power supply ports - one for 12-24V AC, and the other for 11-36V DC power. Only one of these inputs is required to be powered at any one time.
  • connector Jl This is provided through connector Jl , and is required to be externally isolated with respect to board GND, which is used for much of the board's I/O.
  • the connector type is a Weidmuller LM2NZF 5.08/04/135 3.5SN OR BX.
  • the pin assignment for this connector is given in Table 10.
  • connector J2 This is provided through connector J2, and is required to either be externally isolated with respect to board GND, or its negative wire must be at the board's GND potential, as the negative terminal is internally connected to the board's power GND.
  • the connector type is a Weidmuller LM2NZF 5.08/06/135 3.5SN OR BX. The pin assignment for this connector is given in Table 1 1.
  • General Purpose Analogue and Digital Input/Output Port A (GPADIO-A) J3 (see Table 12 for pin assignment) is a general -purpose analogue and digital input/output port, consisting of:
  • J3 is a 34-way right-angle IDC locking header, similar to that shown in Figure 3.
  • the pins of J3 are also repeated in the phoenix connectors J3A to J3E (see Table 14 to Table 20 for pin assignments).
  • GPADIO Port A contains 8 general purpose digital input pins, provided through connector J3.
  • the MultiTrax component contains two analogue input pins, for analogue-to-digital conversion, provided through connector J3. Each pin has a resolution of 10 bits, and its range can be selected using DIP switches between 0-2.5V or 0-1 OV. Each pin is also over-voltage protected to 100V continuous, and low-pass filtered to 100kHz, for EMC (and anti-aliasing).
  • the MultiTrax component contains two analogue output ports, for digital-to- analogue conversion to currents, provided through connector J3. Each port has a resolution of 16 bits, and can output between 0-20mA. Each output (high-side and low-side) has a voltage range of 0-10V. The interface has a maximum bandwidth of 1kHz. To convert the output to a voltage a user may connect the low side to GND via a 470 ⁇ resistor, and connect the high side directly to the 12V rail.
  • J3 and J3E contains a +3.3V general-purpose digital I/O pin.
  • the GPADIO-B port (J5) contains 5 analogue voltage output pins with a range of 0- 3.3V, and two general-purpose +3.3V digital voltage input/output pins (see Table 19 for pin assignment).
  • the connector for this port is a 10-way 0. l"-pitch IDC locking header.
  • the MultiTrax component contains 8 general purpose digital output pins, provided through connector J4. Each pin is a low-side switching open-drain MOSFET output.
  • J4 is identical to that of the Weidmuller RSM 8-channel relay adapter board (Weidmuller part no. 0122800000 / 03834000000 / 02364000000). J4 is a 10-way IDC locking header.
  • J8 is a 2-bit +3.3 V general-purpose digital I/O port (GPDIO) with pin assignment shown in Table 20.
  • the LCD module port, Jl 2 is for connection of an SPI-compatible LCD via a custom adapter board.
  • the connector is a 10-way IDC locking header with pin assignment shown in Table 21.
  • J6 is a dual +3.3V serial / general purpose digital I/O port, with pin assignment given in Table 18.
  • the connector is a 10-way IDC locking header. Port 0 may not be in use simultaneously with RS-232, and port 1 may not be in use simultaneously with RS-485, as these share microcontroller internal USART modules respectively.
  • the MultiTrax component contains a high-impedance digital audio analogue output port interface, J7 (3.5mm stereo socket), for connecting external analogue audio equipment.
  • This port also forms the UHF transmitter auxiliary input and is effective when overridden by a low- impedance signal on this port.
  • the audio inputs and outputs are also included in a 5-way SIL header, J 19.
  • the MultiTrax component contains a high-impedance digital audio analogue input port interface, J18 (3.5mm stereo socket), for connecting external analogue audio equipment. This port also forms the UHF transmitter auxiliary output but is effective as an input when overridden by a low-impedance signal source.
  • the audio inputs and outputs are also included in a 5-way SIL header, Jl 9.
  • J19 is a SIL 5-way header which includes the audio inputs and outputs of J7 and Jl 8.
  • Jl 9 has pin assignment given in Table 23.
  • a software-configurable RS-232 interface is provided through J9, a (male shell, female pin) DB9 connector which complies with the DB9 RS-232 standard pinout.
  • the MultiTrax component operates as a Data Circuit-Terminating Equipment (DCE, peripheral) via this port, and is therefore able to take on the functionality of a traditional serial port modem, if running appropriate software.
  • DCE Data Circuit-Terminating Equipment
  • the MultiTrax component contains an RS-485 connector, J10, which is an RJ-45 connector for easy connection of commodity unshielded twisted-pair (cat-5 UTP) cables.
  • J10H A footprint for a 10-way IDC locking header, J10H, also provides this interface.
  • the board-to-board connector, J1 1 (pin assignment given in Table 24), contains signals for enabling two adjacent MultiTrax component boards to conveniently communicate.
  • the port consists of a software-configurable master/slave SPI port with IRQ line, enabling the slave to initiate transactions and removing the requirement for the master to poll the slaves.
  • the MultiTrax component contains 3, 50 ⁇ SMB connectors for connecting antennas to each of its 3 radio communications transceivers/receivers:
  • the MultiTrax component contains an On-The-Go (OTG) USB interface (J16, micro-AB connector).
  • OTG On-The-Go
  • the unit may take on the role of a USB host or self-powered device via this interface.
  • the USB interface will automatically detect which mode to operate in, depending upon the type of USB micro plug (A or B) connected.
  • the interface may operate in full-speed (12Mbit/s) and low-speed (1.5Mbit/s), and is of course backwards compatible with external USB 1.1 hosts and devices.
  • a footprint for a 5-pin header, J16H, with pin assignment given in Table 25 also provides this interface.
  • a DIP switch provides an override of the USB-ID pin of the microcontroller to short it to GND, in the case that the MultiTrax component is to behave as a USB host when using the header.
  • the MultiTrax component contains a wired Ethernet interface connected via its RJ- 45 connector, J 17.
  • the JTAG connector (J20) uses the AVR JTAG de-facto standard pin assignment (see Table 26) and 10-pin box header format.
  • J21 is an optional +3.3V serial port for debugging purpose for the GPRS transceiver. It is connected internally to the GPRS module's secondary serial interface intended for debugging, and has pin assignment as given in Table 27. J21 is a 5-pin SIL header.
  • J22 is an optional +3.3V serial port for debugging purpose for the GPS transceiver. It is connected internally to the GPS module's second serial interface, and has pin assignment as giVen in Table 28. J22 is a 5-pin SIL header.
  • J23 is an optional port for debugging baseband signals for the UHF transceiver.
  • J23 has pin assignment as in Table 29 and is a 5-pin SIL header.
  • the preferred embodiment of the MultiTrax component has the following radio interfaces:
  • GPS Global Positioning System
  • the PCB is to be no more 200mm x 120mm x 50mm in size.
  • the board has 6 M3 mounting holes - 4 in each corner, and 2 at the middle point of the longer sides. Along the bottom edge of the board, locking IDC headers are available for connecting the board to application-specific boards.
  • the board should weigh no more than 200g.
  • the MultiTrax component's main microcontroller runs the free real-time operating system (RTOS) FreeRTOS, however in future versions the IEC61508 SIL-3 certified SafeRTOS may be used.
  • RTOS free real-time operating system
  • SafeRTOS is based on FreeRTOS, and porting code from FreeRTOS to SafeRTOS is straight-forward, so it is envisaged that this RTOS upgrade in future will be trivial.
  • the software includes a FAT-16 file system library to aid reading and writing of data to/from the SD card.
  • the software structure is based on a standard API interface to upper level applications.
  • the API interfaces with lower level hardware providing a standard interface easier upper level coding.
  • the most important component in the apparatus of the present invention is the in vehicle unit (IVU) described briefly above.
  • the IVU of the preferred embodiment is a UHF radio receiver which is plugged in between a vehicle stereo unit and the power/speaker cabling. When the IVU receives a warning message it directs the incoming message to the vehicle speakers. It also controls the power to the speakers such that it can disconnect or override the signal from the stereo to the speakers, and/or power the speakers if the stereo is off.
  • the schematic location according to the preferred embodiment of the IVU in relation to the vehicle stereo, speakers and power supply is shown in Figure 8.
  • the IVU also has the ability to receive data messages via UHF, which it passes on to an external in- vehicle computer via a serial cable connection, or via and optional Bluetooth transceiver.
  • the IVU also has the optional ability to function as a Bluetooth mobile phone hands free kit. This uses the vehicle's speaker system and a microphone which is installed in the vehicle and plugs into the IVU.
  • the IVU carries out a self-test by transmitting a small test signal to itself. If it does not confirm it is operating correctly the speakers will remain muted; thus notifying the vehicle's operator of the IVU' s failure.
  • Figure 9 provides a functional overview of the IVU and its major internal components.
  • the IVU contains a Texas Instruments MSP430F2132 as its principal
  • This IC has 512 bytes of SRAM, eight 10-bit ADC channels, 24 GPIO pins, two 16-bit timers, 8KB of flash program memory, 256 bytes of flash data memory, 3 capture/compare registers, a serial communications interface and an SPI interface.
  • a 16MHz crystal oscillator is used as the clock for this microcontroller as it requires maximum performance and accurate timing to measure CTCSS tones.IVUs may only be programmed via the JTAG interface connector P900.
  • a suitable Spy-bi-wire MSP430 JTAG programming adapter and programming software can be used for programming.
  • the receiver is a dual conversion superheterodyne with a front-side low-noise amplifier (LNA).
  • the UHF receiver contains a TB31202 PLL whose frequency is adjustable by the microcontroller via SPI.
  • An MC3372 FM IF demodulator IC is used, which provides an RSSI input to microcontroller ADC channel 2.
  • the first mixer is based around the BF998 dual-gate MOSFET. Refer to section 4 for detailed radio specifications.
  • the PLL is to be capable of locking to a frequency outside of the front-side RF band-pass filters as a "quiet" frequency for the POST (see section 6.1).
  • the IVU RF communications employ a continuous tone-coded squelch system (CTCSS).
  • CTCSS continuous tone-coded squelch system
  • the baseband signal is directed through a 60Hz-260Hz band-pass filter, which is then connected to an interrupt input pin of the microcontroller, allowing CTCSS tone frequencies to be measured in firmware, and therefore firmware-configurable.
  • the IVU will optionally contain an internal Bluetooth chipset and on-board
  • Bluetooth antenna This allows the IVU to act as a mobile phone hands-free system, as well as allowing the IVU to communicate with nearby computing devices. Such computing devices may then be used to configure the IVU during installation or maintenance, as well as receive UHF- transmitted data.
  • the internal UHF transmitter uses a clock output from the microcontroller which is band-pass filtered to yield the 432MHz harmonic of the 16MHz clock signal. This is activated only for the first 5s after power-up.
  • the board contains 4 DPDT relays, 2 of which are for switching the front speakers between stereo and IVU audio outputs, and 2 of which are for opening the 4 rear/other speaker circuits (muting).
  • the front speaker relays switch both positive and negative speaker outputs between head unit and IVU audio amplifier, but only the positive outputs are switched between closed and open circuit for the rear/other speaker channels.
  • These relays, along with the telephone mute function of the stereo, are individually interfaced to the microcontroller, allowing software to delay to ensure a 100ms time lag between mute line activation and relay switching, as well as the reverse.
  • the audio amplifier is an MP7720-based class-D amplifier to reduce heat dissipation. This single ended amplifier is connected to both front speaker outputs. Audio gain is controlled via the digital potentiometer (section 2.9). The amplifier is designed not to sustain damage in the case of shortcircuited speaker outputs. This amplifier is capable of outputting 20W RMS continuous at 90% efficiency.
  • a differential amplifier is used to convert the head unit's front left speaker output to a ground-referenced signal for input to the microcontroller, so it can count the audio signal frequency, in the case that the unit receives a portable calibration unit (PCU) radio signal. This is to confirm that the IVU is being calibrated, and that the PCU radio signal is not a stray signal from another IVU being calibrated.
  • PCU portable calibration unit
  • the IVU board contains an AD5165 digital potentiometer which the microcontroller accesses via the SPI bus to control the audio amplifier gain.
  • the IVU contains an internal linearly-polarised UHF helical antenna, which is oriented lengthways within the enclosure.
  • an SMB connector is mounted on the same PCB footprint, allowing external antennas to be connected.
  • the unit contains 5 linear voltage regulators: 1. 5 V for RF and analogue circuits.
  • Class-D audio amplifier supplied directly from power input.
  • a 3A fuse is contained in the unit to prevent overheating and over-current in case of malfunction.
  • the IVU of the preferred embodiment has a number of external interfaces.
  • the IVU of the preferred embodiment has the following communications interfaces: 1.
  • the IVU acts as a receiver, receiving signals from OBUs (Crossing type 1 case and failure of RSU in crossing types 2 and 3 case) or RSUs.
  • the IVU of the preferred embodiment has the following External Electrical Interfaces: 1. Vehicle Power input.
  • Head unit telephone mute signal 4. Speaker inputs (from vehicle's head unit)
  • the IVU is able to operate from a 12-24VDC supply with a negative chassis only.
  • the IVU connects to power using an ISO 10487 standard power (type A socket) connector, P2, and passes on power to the audio system using P3, a type A plug of the same standard. Between power connectors, the IVU can pass up to 10A of current through the Earth (0V) and switched +12-24V rails, and up to 1 A on all other rails.
  • the IVU only draws current from the switched DC supply (pin 7 of the ISO 10487 connector).
  • the IVU draws ⁇ 500mA of quiescent current, and ⁇ 1A when receiving and playing a warning message over the front speakers.
  • the IVU draws non-negligible current, it is advised that it is wired correctly as in Figure 3, to only be supplied with power when the vehicle is in use (e.g. when ignition key in "accessories” or “on” position), to prevent draining of batteries.
  • the IVU may draw a maximum of 3A of current.
  • the mute function of the stereo is used via pin 1 of the type A connector, if available, as an extra precaution to prevent damage to the stereo's speaker outputs when disconnecting the speakers.
  • the IVU of the preferred embodiment is connected to the head unit' s speaker outputs.
  • the IVU can switch off up to 6 speaker channels, 2 of which (front speakers) it can relay warning audio signals. Switches are able to pass up to 30V RMS (with respect to chassis) and 2A of current when not interrupting the normal speaker circuits.
  • the regular 4 speaker inputs are connected through P4, an ISO 10487 plug type B. An additional 2 speaker inputs may be connected through PI .
  • the PCB also includes holed pads for each connector pin to solder wires directly in future if required.
  • the IVU of the preferred embodiment has audio signal outputs.
  • the IVU is able to tolerate minimum speaker impedances of 3.5 Ohms.
  • front speakers must be wired to be electrically floating with respect to chassis potential.
  • Front speakers must be rated to handle 10W RMS continuous audio power at any audio frequency. Up to 6 speakers may be connected to the audio signal output connector, but only 2 of these - the front speakers - will have audio signals from the IVU - the other 4 will only have their circuits opened and closed by ⁇ the IVU.
  • the regular 4 speakers are connected through P6, to which an ISO 10487 socket type B adapter may be connected.
  • An additional 2 speakers may be connected through P5.
  • a set of holed pads are also to be placed on the PCB to allow future direct soldering of adapter wires to the board.
  • the IVU's audio amplifier is short-circuit protected to prevent damage to the unit in the case of accidental shorts of speaker wiring.
  • the design of the IVU of the preferred embodiment allows for an optional external 50 ⁇ SMB antenna edge connector to connect an external antenna.
  • the PCB design allows for easy selection between this connector and the default internal helical antenna (see section 2.10), both using the same PCB footprint.
  • the unit is to be placed close behind the vehicle's audio head unit, or other location behind the dashboard, hidden from the road vehicle driver.
  • the unit is housed in a flanged ABS (plastic) rectangular-prism-shaped enclosure with holed flanges at either end for secure mounting.
  • the IVU should be securely mechanically mounted within the vehicle to reduce fatigue on connectors and wiring, and prevent the unit from causing nuisance vibrations and knocking sounds.
  • the unit may be mounted in any orientation, as the radio frequencies received are circularly polarised.
  • the IVU should weigh no more than 200g excluding external electrical adaptors.
  • the dimensions of the enclosure are 1 14mm x 63mm x 28mm, (138mm long including flanges), and mounting holes sized 5mm separated by 42mm.
  • the enclosure may be any colour.
  • the significant power dissipating components are: 1.
  • the audio power amplifier - 2W maximum (90% efficiency at 20 W) - only dissipating when receiving radio signal.
  • the IVU design allows it to be installed in a vehicle using the following procedure: 1. Remove vehicle audio system head unit or use some other means to gain access to audio system wiring.
  • the unit is not designed to be repaired - in the case of malfunction the unit must be replaced.
  • the unit may be recalibrated at any time using a portable calibration unit.
  • the firmware is not field upgradeable, it may only be programmed in the factory or by an authorised service person.
  • the behaviour of the IVU is characterised by the flow charts of Figure 10 though Figure 13. On power-up the behaviour is described by the power-on self-test (POST) flow chart of Figure 10. If the POST is successful, the IVU behaves as per the idle/scanning flow-chart of Figure 1 1. When an IVU transmission is received, the IVU behaves as per the receiving signal flow-chart of Figure 12, unless the transmission is from a portable calibration unit, in which case it behaves as per the calibrating flow chart of Figure 13 (as indicated in the idle/scanning flowchart).
  • POST power-on self-test
  • the software is designed to exhibit the following behaviours in order to reduce message repetition and reduce occurrences of missing higher-priority messages: 1. Scans radio channels from highest to lowest priority, so highest-priority messages are most likely to be received, and received before lower-priority messages.
  • the IVU When finished playing an audio message, the IVU restarts scanning from the highest- priority channel again, not continuing to lower-priority channels than the one played. 5.
  • the unit times the length of an audio message. If it is longer than a maximum period of 5s, it temporarily abandons playing the message to scan higher-priority channels. If the other channels are silent, it continues playing the message for another 5 s, and so on. 6.
  • the unit only plays audio messages when receiving radio signals above a certain signal strength threshold.
  • the unit recognises audio messages from some radio signals below the signal strength threshold, but doesn't play them. It uses this knowledge to ensure it correctly plays a full message, and does not miss the start of a message, in the case the transmitter comes into range mid-message.
  • the unit When scanning, if the unit recognises FS data, mid-packet, it waits up to 1 s for a full packet to be re-transmitted.
  • the unit When detecting an FSK data signal, the unit stays locked to the channel for up to Is, before moving on to the next channel.
  • the software will not be required to be remotely updatable and will therefore require no bootloader. As it is a simple single-tasking system, it will not require a real-time operating system (RTOS). To maximise portability, re-use and future maintainability the software will be written in C.
  • RTOS real-time operating system
  • the software is to have a well-organised hierarchical structure of modules.
  • Dependencies and function calls are to be one-way only - from higher-level modules to lower-level modules, the lowest level being the microcontroller-hardware interfaces and the highest being the controller module.
  • all changes should also make use of this design principle.
  • the MSP430F2132 microcontroller has only 8KB of program memory, 256 Bytes of non- volatile data memory, and 512 bytes of RAM. Larger amounts of data (e.g. radio frequency tables), are to be hard-coded as constants to prevent them being placed into RAM. Groups of radio frequencies which exist as a linear series of channel frequencies of equal spacing may be suitably put into a compact data type which specifies base frequency, spacing and quantity of frequencies.
  • Function-calling levels are to be no more than 10 layers deep, to reduce the required stack size.
  • the structure is to be modular and hierarchical to prevent two-way calling problems and to maximise code re-use.
  • the software essentially consists of the following modules and sub-modules
  • Controller/main loop module CM
  • ISM Initialisation Sub-Module
  • POSTSM POST sub-module
  • CSM Calibration Sub-Module
  • RSS Receiving Message Sub-Modules
  • ACM Audio Control Module
  • ISM Initialisation sub-module
  • This sub-module calls the required initialisation routines of all other modules on power-up to ensure they can begin to function correctly and serve the CM as required.
  • ISM_Init() This, along with POSTSM_POST, is to complete in less than 3s b) Power-on self-test sub-module (POSTSM)
  • This sub-module performs auto-calibration of the receiver when radio messages from a PCU are received.
  • This sub-module is for receiving a IVU warning message during normal operation of the IVU.
  • Audio Control Module (ACM).
  • ASM Audio amplifier gain and speaker switching/muting control sub-module
  • AMSM Audio measurement sub-module
  • the audio control module controls the audio amplifier gain, reads amplifier output levels, and switches speakers and the telephone mute line of the head unit. Additionally, it determines the tone of the audio being output by the head unit, to determine whether it is signalling a calibration of the IVU.
  • ACM_IVU() Mutes head unit, switches speakers to IVU and sets audio amplifier gain to stored setting.
  • ACM_HeadUnit() Sets audio amplifier gain to zero, switches speakers to head unit and unmutes head unit.
  • ACM_Testing() Switches speakers to head unit, unmutes head unit and sets audio amplifier gain to stored setting.
  • ACM_Fault() Mutes head unit, mutes audio amplifier, and switches speakers to IVU.
  • TAudioLevel ACM_GetAudioLevel() Measures audio level from audio amplifier output, for POST.
  • Boolean ACM CalibrationToneMatchO - Returns whether the frequency of the audio input from the head unit matches the calibration tone. This is used to confirm that the unit is being calibrated.
  • ACM_HeadUnitPulse() Called once every head unit audio signal cycle, and used to determine head unit audio output frequency.
  • RCM Radio Communications Receiver module
  • the radio communications receiver module provides all functionality for receiving radio messages, including CTCSS signalling.
  • CTCSS tone sub-module (CTSM).
  • UHF receiver controller sub-module UHF receiver controller sub-module
  • TChanID RCM_GetChan() Gets the channel which the receiver is currently locked to.
  • TRSSIStatus RCM CheckRSSIO - Indicates whether received signal is within range, out of range or non-existent.
  • TRxCTCSSStatus RCM_CheckCTCSS() -Returns whether the CTCSS tone is valid for the current channel.
  • RCM_CalibrateRSSI Saves the current RSSI as the squelch threshold.
  • Boolean RCM_QuietChan() Locks tuner to the designated quiet channel, in which there is no RF signal. Returns true if successful, false if failure. 8.
  • Boolean RCM_POSTTxChan() Locks tuner to the designated internal test transmitter frequency. Returns true if successful, false if failure.
  • RCM_SetRxDataCallback(function pointer) Sets the data callback function for receiving bytes over UHF. This allows the radio communications module to pass received bytes back to higher level functions.
  • the settings module provides a central repository of settings which other modules may call upon. Some settings are hard-coded as C code, while others may be stored in nonvolatile memory. The settings stored consist of:
  • Audio gain setting (Non- volatile memory)
  • TChanID SM_GetQTYChannels() Gets the quantity of channels listed in the settings table.
  • TRSSI 16-bit unsigned integer representing RSSI ADC reading.
  • TCTCSSPeriod 8-bit unsigned integer representing period of CTCSS tone in ' lOOus.
  • TRadioFreq - 16-bit unsigned integer representing radio frequency, such that x (f- 400MHz) /2kHz.
  • TChanData - Structure contains:
  • TSM Tone measurement sub-module
  • the timer module provides a mechanism for other modules to accurately measure or wait for a period of time. This can be used for tasks such as CTCSS tone measurement, or waiting for a period of time before scanning frequencies or completing a power-on self- test, etc.
  • TM Wait(TusCount) Waits for the given period of time before returning.
  • TM_StartTimer(TTimer, TusCount) Starts a timer
  • TM_Overflow() Called when the 16-bit hardware timer register overflows.
  • TusCount 32-bit unsigned integer representing a microsecond count.
  • HW Hardware abstraction layer module
  • HW_PLLSetReference(unsigned int) - Sets reference oscillator divider.
  • HW_DigiPotTx(char) Transmit a byte to the audio gain digital potentiometer.
  • Unsigned short HW_ADCReadRSSI() Reads the RSSI from the ADC.
  • Unsigned short HW_ADCReadAudioLevel() Reads the audio power amplifier signal level from the ADC.
  • Unsigned short HW_ADCReadTemperature() Reads the temperature from the microcontroller's internal temperature sensor.
  • HW_SetCTCSS_ISR Sets the CTCSS interrupt service routine callback function.
  • HW EnableFSK(boolean) Enables or disables FSK demodulation interrupt service routine.
  • HW_Set_HUAudioTone_ISR(function pointer) Sets the head unit audio tone interrupt service routine callback function.
  • HW_FlashWrite(Data, Size) Writes the given data to the non-volatile flash data storage area of the microcontroller.
  • HW_SetNotchTunePWMValue(unsigned short) - Sets the notch filter tuning PWM value.
  • HW_SetRefTunePWMValue(unsigned short) - Sets the PLL reference oscillator tuning PWM value.
  • HW_Set2ndLOTunePWMValue(unsigned short) - Sets the 2nd local oscillator tuning PWM value.
  • HW_SerialTxByte(char) - Transmits a byte out of the wired serial
  • HW_SetRxByteISR(function pointer) - Sets the callback function for receiving byte from the wired serial communications port.
  • HW_SerialTxString(string) - Transmits a string out of the wired serial communications port.
  • HW_ServicePendingTimerInterrupt() Services any pending timer overflow interrupts, and is required to be called during service of any other interrupt when attempting to read the timer.
  • the IVU software has a hierarchical modular structure to maximise software reliability, maintainability and code re-use for other projects.
  • the arrows in Figure 14 are in direction of control (i.e. function-calling).
  • the wired serial port includes a configuration and status interface, which enables external computers/terminals to configure IVU settings and receive updates about IVU status.
  • the interface reports RSSI once per second.
  • the IVU does not output the bit sync and frame sync bytes, only the content of each packet.
  • the IVU also does not perform checksums on the data packets, it simply relays the raw data it receives. It is up to the higher-level software to perform checksums, etc, to determine packet validity.
  • the IVU only relays data When it receives a full 9 bytes after the frame sync.
  • Radio receiver tunes to quiet channel and confirms white noise level on amplifier output. 4. Radio receiver tunes to internal transmitter and confirms silence on amplifier output. 5. Less than 3 s since power-on.
  • IVU enters receiving message state.
  • Speakers switch to IVU and head unit muted.
  • Valid radio signal continues to be received by IVU, and continues to be relayed to audio speakers.
  • IVU recognises that it has now heard the start of the message.
  • Valid radio signal continues to be received by IVU, and continues to be relayed to audio speakers, with volume high enough to compensate for ambient noise detected on microphone.
  • Valid radio signal continues to be received by IVU, and continues to be relayed to audio speakers.
  • IVU recognises that it has now heard the full message, but maintains message count for this channel:
  • IVU resets message count to zero for channel.
  • IVU scans for lower-priority signals.
  • IVU retains squelch RSSI and audio gain settings now calibrated.
  • Radio receiver tunes to quiet channel but no white noise level is measured on amplifier output.
  • Radio signal is received on valid IVU channel/frequency, but contains incorrect CTCSS tone.
  • Radio signal is received on valid IVU channel/frequency, with correct CTCSS tone, but signal strength weaker than calibrated squelch strength.
  • a higher-priority valid radio signal is received by the IVU.
  • IVU recognises this high-priority message within 4 seconds, and IVU enters receiving message state.
  • Radio receiver tunes to quiet channel and white noise level is measured on amplifier output.
  • Radio receiver tunes to internal UHF transmitter frequency, and white noise level is still measured on amplifier output.
  • IVU demodulates FSK data.
  • IVU finds packet frame sync bytes.
  • IVU passes on data following frame sync bytes out of wired serial port.
  • IVU demodulates FSK data.
  • IVU does not find packet frame sync bytes.
  • IVU does not pass on data following frame sync bytes out of wired serial port.
  • This radio communications interface is for transmitting warning signals from rail infrastructure and trains to in- vehicle units (IVUs) located in road vehicles. It is a one-way interface, IVUs only ever receive communications using this interface. It is a direct point-to-point analogue and digital radio communications interface - there is no network or nodes which relay communications using this interface. All valid warning messages received by IVUs are passed to in-vehicle audio speakers in real time.
  • IVUs in- vehicle units
  • a UHF audio transmission is the preferred means by which to notify road vehicle operators of hazards because the transmission/broadcast:
  • the signal is a frequency-modulated UHF transmission, modulated with either a human understandable audio signal superimposed with a sub-audio CTCSS tone for switching purposes or modulated by a 2400bps FSK data stream.
  • the carrier may be any frequency in the range of 400 to 470MHz.
  • the channels spacing is 12.5kHz.
  • the 433MHz ISM band is used internally within IVU receivers as a test signal on power-up, and is not used for any other purpose.
  • This band covers 433.05 - 434.79MHz, and allows for up to 25mW of equivalent isotropically radiated power (EIRP) per transmitter.
  • EIRP equivalent isotropically radiated power
  • Transmitters within the IVUs will be limited to ImW, and their antennas limited to PCB printed monopoles, or F-antenna types.
  • Carrier frequencies will be reserved for the PCU. ISM bands will not suffice for this purpose, as PCU's will be required to transmit power of the same order of magnitude as IVU warning transmitters (1 W) - too powerful to be deemed low interference potential devices (LIPDs).
  • ISM bands will not suffice for this purpose, as PCU's will be required to transmit power of the same order of magnitude as IVU warning transmitters (1 W) - too powerful to be deemed low interference potential devices (LIPDs).
  • LIPDs low interference potential devices
  • the bandwidth is also to be BT ⁇ 12.5kHz. Given a modulating signal bandwidth of 3kHz, this should be a maximum ⁇ 4.5kHz peak instantaneous deviation of the carrier frequency.
  • the audio baseband signal consists of a human-understandable 300Hz to 3kHz audio signal added to a 60Hz-260Hz CTCSS single-frequency tone.
  • the preferred IVU is a human-understandable 300Hz to 3kHz audio signal added to a 60Hz-260Hz CTCSS single-frequency tone.
  • the FSK baseband signal consists of the FSK signal only (no CTCSS).
  • Figure 16 is an illustration of an IVU Communications Baseband Spectrum for an FSK data transmission.
  • Continuous Time-Coded Squelch System is a continuous single-frequency sub-audio (67Hz-257Hz) tone added to the baseband audio signal. It is used in the IVU communications interface to indicate that a transmission is audio. An IVU will only open the squelch when it receives a signal with the correct CTCSS tone frequency for the carrier frequency and channel received.
  • CTCSS is not intended to provide comprehensive security against intended misuse of the IVU communications interface.
  • an attacker with a CTCSS-equipped UHF transceiver would be able to generate unauthorised IVU transmissions, which any IVUs within range will relay to speakers.
  • a digitally-coded squelch system may be used, with additional encryption measures to securely prevent unauthorised misuse.
  • CTCSS tones of 50Hz, or multiples thereof, must not be used due to this being the mains power frequency, and possibly causing nuisance triggering of the squelch in IVUs.
  • a 71.9Hz CTCSS tone is used for PCU calibration signals.
  • CTCSS is not used for FSK data transmissions.
  • the audio frequency ranges from 300Hz to 3kHz, and has arbitrary content (i.e. may be speech, sirens, chimes, or other messages as determined by human factors studies). If the audio content is a repeated message, the break between repetitions should be marked with a break in the CTCSS tone of no less than 0.2s. This allows receivers to only relay a complete message once, instead of continuously relaying the message as it repeats.
  • the 2400baud FSK signal uses two tones - 1200Hz and 2400Hz, with 1200Hz corresponding to "1" and 2400Hz corresponding to "0".
  • a single logic 1 bit is indicated by a half wavelength of a 1200Hz sine wave and a single 0 bit is indicated by a full wavelength of a 2400Hz sine wave.
  • the sine wave frequency always changes at the zero crossing of the wave.
  • the data transmission consists of at least two bit synchronisation bytes (two AA16), followed by two frame synchronisation bytes (C416 and D716), and then a payload of data bytes.
  • the end of the data packet is indicated by either a loss of carrier or a loss of FSK modulation.
  • An IVU transmission consists of the following sequence (illustrated in Figure 17): 1. ⁇ 1 s of carrier wave modulated by CTCSS single tone only. This allows time for receivers to scan to carrier frequency, recognise CTCSS tone, and switch speakers to receiver before the start of the audio message. 2. Arbitrary time length of carrier wave modulated by audio message + CTCSS single tone, as long as required. 3. ⁇ 0.2s of unmodulated carrier wave only. This allows the receiver time to recognise loss of CTCSS tone and switch audio gain to zero before a white noise signal is relayed to the speakers.
  • An IVU transmission of a repetitive message consists of the following sequence (illustrated in Figure 18): 1. ⁇ 1s of carrier wave modulated by CTCSS single tone only. This allows time for receivers to scan to carrier frequency, recognise CTCSS tone, and switch speakers to receiver before the start of the audio message. 2; Arbitrary time length of carrier wave modulated by audio message + CTCSS single tone, as long as required. 3. ⁇ 0.2s of unmodulated carrier wave only. This marks the end of the message, and allows time for the receivers to quickly scan for other higher-priority messages. 4. ⁇ 0.2s of carrier wave modulated by CTCSS single tone only. This allows time for the scanning receivers to recognise that the message is about to restart. 5. Repeat steps 2 to 4 as many times as the message needs to be broadcast. 6. ⁇ 0.2s of unmodulated carrier wave only. This allows the receiver time to recognise loss of CTCSS tone and switch audio gain to zero before a white noise signal is relayed to the speakers.
  • the PCU transmission sequence is identical to the normal use transmission sequence, except the time length of the CTCSS tone has significance.
  • the PCU is to cease the CTCSS tone the instant that the sound pressure level within the cabin meets specification.
  • a preferred form is illustrated in Figure 19.
  • a data-only transmission may be useful in some situations.
  • An IVU transmission of a data-only message consists of the following sequence (illustrated in Figure 20): 1. ⁇ 0.5s of carrier wave modulated by FSK idle tone. This allows time for receivers to scan to carrier frequency and recognise FSK idle tone before the start of the data message.
  • the audio band signal should be the designated idle tone of FSK.
  • FSK data message This should take as long as is required to transmit the arbitrary data message.
  • a transmitter may arbitrarily transmit audio or data to IVUs as long as the transmission meets the following requirements: 1.
  • the carrier must begin at least Is before the start of the analogue audio signal, to allow enough time for the scanning IVU to detect the carrier and CTCSS tone and switch speaker relays to the IVU.
  • the designated CTCSS tone must begin and continue at least Is before the start of the audio transmission. This is required to ensure that scanning receivers have enough time to detect the transmission and recognise that it is a valid transmission, due to the valid CTCSS tone, and stay locked to that frequency. c.
  • the CTCSS tone must cease at least 0.2s before the carrier ceases, so the IVU has enough time to detect the end of the message before a noise signal is sent to the vehicle's speakers.
  • FSK data must not be present while the CTCSS signal is present.
  • FSK data signal must cease at least 0.2s before the start of the audio message, or the end of the carrier.
  • FSK data must not begin until at least 0.1 s after the designated audio CTCSS tone ends. 2.
  • the carrier must begin at least 0.5s before the start of the FSK data transmission, to ensure that scanning receivers have enough time to detect the transmission.
  • the carrier should continue for at least 0.1s after the end of the FSK data so the IVU is able to decode to the end of the packet.
  • the IVU will have a squelch opening threshold which can be configured from - 1 lOdBm to -45dBm, however -75dBm is the preferred and nominal setting.
  • IVU receivers will contain their own internal helical linearly-polarised receiving antennas (with ⁇ 0dB gain) and will be installed behind the dashboards of road vehicles, the vehicles themselves will attenuate the IVU radiation significantly before it reaches the IVU receiver antenna.
  • Measurement trials have determined that there is 10-20dB attenuation from outside of the road vehicle to the internal receiving antenna. The result is an accepted threshold ambient power level of 50dBm.
  • the link budget has a surplus of 40dB to allow for excessively lossy road vehicle installations.
  • the UHF antennas are configured to direct radiation along the roadways adjacent to the crossings for an effective distance of dWV to provide sufficient warning for oncoming road vehicles.
  • Antennas and attenuators must be adjusted to provide at least the threshold far-field radiation level specified in section 3.5, within the desired warning zone alone these roadways. Care is taken during installation to minimise stray radiation to minimise nuisance IVU activation in cases such as road vehicles parked close to the level crossing. This is illustrated in Figure 21.
  • the IVU transmission is circularly polarised, as the IVU uses an internal linearly- polarised antenna with arbitrary orientation.
  • Appropriate circularly-polarised crossed Yagi-Uda directional antennas may be used to direct radiation along adjacent roadways. Two to six such antennas may be used, depending on the topology of the adjacent roads and intersections. This is illustrated in one form for a T intersection in Figure 22.
  • the UHF antenna on the train transmits the IVU warning signals directly to passing road vehicles using an omnidirectional linearly polarised antenna (see Figure 23).
  • An omnidirectional antenna must be used on the train to account for all road topologies and train configurations (i.e. Locomotives may be travelling in reverse).
  • the radiation levels emitted by the OBUs must also be high enough to ensure that when it is within the warning range of a type 1 crossing, that the adjacent roads all receive this minimum radiation level.
  • rVUs contain an internal linearly-polarised antenna. As the transmitted signal is circularly polarised, the IVU may be arbitrarily oriented within a vehicle. [00372] A PCU is to transmit at power levels which produce the specified threshold ambient radiation levels upon the outside of the road vehicle, that a vehicle would experience entering a warning zone. An IVU then saves this received radiation level as its squelch opening threshold.

Abstract

The invention relates to an apparatus for a radio break-in transmission and particularly to a distributed network of mobile and fixed radio transceivers and receivers, centered on rail networks and road vehicles. An in-vehicle unit for a radio interruption system is to be connected in a vehicle, which comprises a processor, an internal receiver for receiving a signal, an internal transmitter for transmitting a signal, a peripheral interface of the processor wherein the unit receives a warning message, the processor interrupts a normal signal being played/broadcasted to vehicle speakers and issues the warning message through the vehicle speakers.

Description

AN APPARATUS FOR RADIO BREAK-IN
TECHNICAL FIELD
[001 ] The present invention relates to an apparatus for radio break-in and particularly to a distributed network of mobile and fixed radio transceivers and receivers, centred on rail networks and road vehicles.
BACKGROUND ART
[002] If motorists are given more time to react to potentially dangerous situations, the decisions taken to avoid these situations would be improved. To improve a motorists' decision making whilst approaching a crossing, they must be informed of the presence of a locomotive, and whether this locomotive is approaching an intersection or is across the intersection.
[003] There are problems with existing warning signals to communicate to motorists that danger may be ahead. Visual warnings rely on the driver to be looking, reading and
concentrating on signage whilst watching the road, negotiating traffic, checking instrumentation and navigating; at times whilst distracted. Visual warnings can be obscured by bad weather conditions such as fog or heavy rain or by temporary obstructions (such as a truck parked near signage). Driver behavior plays a major role in the effect of visual warnings. Drivers become complacent and, if they are lucky, only have close calls to remind them of the dangers on the road.
[004] Audible warnings, such as sirens and horns produced from locations outside of the vehicle, can remain unheard by motorists due to vehicle insulation and loud sound systems.
[005] Railway level crossings have passive or active controls to guide road users.
[006] Passive: have static warning signs (stop or give way signs) that are visible on approach. This signage is unchanging with no mechanical aspects or light devices.
[007] Active: in addition to passive railway level crossing signage, these are controlled by automatic warning systems. Including flashing lights, automatic gates (booms, boom gates); audible devices (bells, gongs), advanced warning signs or other warning devices are activated by approaching trains.
[008] Existing detection systems comprise trackside loop configurations and have become an unofficial standard worldwide. They are a very resilient system capable of giving appropriate warning in a timely manner but can be subject to false triggering. They are costly to install and it is considered not reasonably practical to protect all level crossings in this manner. Their integrity is reliant on duplicate / backup redundancies and therefore capable of failing wrong side.
[009] The road to rail crossing environment is not homogenous and therefore each crossing must have a risk assessment performed to validate the level of protection required. Ideally each crossing would have full protection, but for many reasons, this is neither feasible or economically viable.
[0010] An integrated, multi-layer; fail to safe system capable of protecting a wide variety of level crossings in a cost effective manner is therefore required
[0011 ] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.
SUMMARY OF INVENTION
[0012] The present invention is directed to an apparatus for radio break-in which may at least partially overcome at least 'one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.
[0013] With the foregoing in view, the present invention in one form, resides broadly in an in-vehicle unit for a radio interruption system, the unit adapted to be connected between an existing vehicle stereo head unit and vehicle's speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a signal, an internal transmitter for transmitting a signal, at least a pair of audio switching relays, a first switching relay to switch both positive and negative speaker outputs between the vehicle head unit and a first set of vehicle speakers and a second switching relay to switch only positive speaker outputs between closed and open for the vehicle head unit and a second set of vehicle speakers, and at least one processor peripheral interface wherein when the unit receives a warning message, the processor interrupts a normal signal from the existing vehicle stereo head unit to all of the vehicle speakers, and directs the warning message to the first set of vehicle speakers.
[0014] In an alternative form, the present invention resides in a multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly or implements instructions based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly, based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
[0015] In another alternative form, the present invention resides in an on board unit for a moving vehicle, the on-board unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
[0016] In another alternative form, the present invention resides in a road side unit for use with fixed transport infrastructure, the road side unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to actuate a change in the fixed transport infrastructure based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
[0017] In yet a further form, the present invention resides in a radio break-in apparatus including an in- vehicle unit associated with a member vehicle in a first category, the in vehicle unit adapted to be connected between an existing vehicle stereo head unit and vehicle speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a radio break-in signal, an internal transmitter for transmitting a signal, and at least one processor peripheral interface, an on-board unit associated with a member vehicle in a second category, the on-board unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly a roadside unit associated with at least one piece of fixed transport infrastructure, the road side unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to actuate a change in the fixed transport infrastructure based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly wherein when a member vehicle in a second category approaches a piece of fixed transport infrastructure with a roadside unit, the onboard unit issues a radio transmission to the roadside unit which upon receipt of the radio transmission, actuates a change in the mode of the fixed transport infrastructure to indicate the approach of a member vehicle in a second category and the roadside unit broadcasts a radio break-in transmission which when received by an in- vehicle unit of a member vehicle of the first category, the processor interrupts a normal signal from the existing vehicle stereo head unit to the vehicle speakers, and issues a warning message to vehicle speakers.
[0018] In yet a further form, the present invention resides in a radio break-in apparatus including an in-vehicle unit associated with a member vehicle in a first category, the in vehicle unit adapted to be connected between an existing vehicle stereo head unit and vehicle speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a radio break-in signal, an internal transmitter for transmitting a signal, and at least one processor peripheral interface, an on-board unit associated with a member vehicle in a second category, the on-board unit including at least one
multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly wherein when a member vehicle in a second category approaches a piece of fixed transport infrastructure, the onboard unit broadcasts a radio break-in transmission, which when received by an in-vehicle unit of a member vehicle of the first category, the processor interrupts a normal signal from the existing vehicle stereo head unit to the vehicle speakers, and issues a warning message to vehicle speakers.
[0019] A radio break-in transmission can be issued to a member vehicle of the first category from active infrastructure or from an on-board unit in a directed manner, and/or from the active infrastructure or on-board unit as a broadcast radio break-in transmission.
[0020] The GPS receiver and transceiver of the member vehicle of the second category will typically be associated with a computer processor. The processor will typically be preloaded or have access to the location information of all infrastructure within the system, whether fixed infrastructure or mobile infrastructure and/or member vehicles of the second category including itself.
[0021 ] Updating of the relative positions of infrastructure and/or member vehicles within the system will preferably be via a real time link such that the positions of infrastructure and/or member vehicles are represented in real time.
[0022] The processor will typically register or calculate the position of member vehicles relative to each other and/or other elements of infrastructure, in particular fixed infrastructure where changes in mode of operation are required or mobile infrastructure where collision avoidance is required.
[0023] Examples of fixed infrastructure within the system include fixed transport infrastructure such as controlling lights, intersections, level crossings, and other points of interest such as buildings or hospitals. Examples of mobile infrastructure include other member vehicles and other moving obstacles which may not be members of the system.
[0024] Typically, the on-board unit will issue a radio transmission to transport infrastructure dependent upon proximity of an approaching member vehicle. The locating device on each member vehicle maintains a position of the member vehicle and an on board unit is preferably configured to calculate distance, approach velocity and time of a member vehicle of the second category to any transport infrastructure, and transmit a signal once the member vehicle crosses a point at a predetermined time from the transport infrastructure.
[0025] Typically, the transceiver will transmit a radio transmission in one or both of a broadcast and a directed manner. Where the directed signal is transmitted, the signal will typically be directed at the transport infrastructure to trigger a response from the infrastructure which may be in the form of a return signal or an action, preferably a change of mode of operation of the transport infrastructure.
[0026] The position of all infrastructure pieces, whether fixed or mobile infrastructure, will preferably be identified to the locating device. There will further preferably be active infrastructure and passive infrastructure with the active infrastructure provided with a receiver and typically also a transmitter to receive a signal from the transmitter of the member vehicle and preferably return a signal to the member vehicle and the passive infrastructure which may be provided with a receiver only. This will typically be accomplished using positioning data or a positioning system such as GPS.
[0027] The GRSS system consists of several types of devices:
■ A locomotive on-board unit (OBU).
■ A roadside unit (RSU), at the road rail crossing.
■ An in vehicle unit (IVU) also known as the PIXIE, installed in road vehicles.
■ A portable calibration unit (PCU).
[0028] Each component interacts to the other components of the system through well- defined interfaces, to facilitate future flexibility in the design and implementations of the components themselves.
[0029] The GRSS system of the present invention is adapted for use on any one or more transport networks including road and rail but is particularly useful in a rail context where the rail intersects with a road network such as at level crossings.
[0030] Railway level crossings typically have either passive or active control to guide road users. Passive rail level crossings normally have static warning signs [stop or give way signs] that are visible on approach. The signage is typically unchanging with no mechanical aspect or lighting devices.
[0031 ] Active rail level crossings typically have the same signage used on passive rail level crossings but also have automatic warning systems including typically flashing lights, automatic gates [booms, or boom gates], portable devices such as bells or sirens, advance warning signs or other warning devices activated by approaching trains.
[0032] The present invention and therefore has three particularly preferred embodiments related to whether a level crossing is passive or active. In a Type 1 , low risk level crossing [these are normally passive level crossings], and onboard unit of a rail vehicle is provided with the location of the level crossing and upon approach, broadcasts a radio transmission once within a particular warning distance of the level crossing which can be received by in vehicle units of member vehicles within range.
[0033] In a Type 2, medium risk level crossing [these are normally passive level crossings provided with a roadside unit of the invention] the onboard unit provided onboard a rail vehicle is provided with the location of the level crossing and upon approach, within a particular warning distance, the onboard unit issues a directed radio transmission to the roadside unit in order to ascertain the status of the roadside unit. If the status of the roadside unit is active, the roadside unit confirm this by return transmission to the onboard unit and also transmits a targeted or directed radio transmission to relevant member vehicles. If the roadside unit is not active, no return transmission is issued and the onboard unit issues a broadcast radio transmission which can be received by in vehicle Units of member vehicles within range.
[0034] In a Type 3, high risk level crossing these are normally active level crossings which are also provided with a roadside unit of the invention], the action is the same as a Type 2 level crossing with the additional step that the transmission from the onboard unit to the roadside unit activates the automated crossing infrastructure. Again, if the status of the roadside unit is not active, the onboard unit will preferably issue a broadcast radio transmission.
[0035] A UHF link is preferably used between components of the system. Once a transmission is received by a component, the processor of the component receiving the transmission will normally implement instructions based on the transmission which are stored in the memory of the component.
[0036] The OBU is an embedded computer system incorporating a UHF transceiver and GPS receiver, which tracks the locomotives location on the rail network and controls the transmission of warning messages to road vehicles, either directly through its local UHF transmitter (Type 1 crossing), or via road-side units (Type 2 and 3 crossings).
[0037] The on board unit is associated typically with a moving vehicle. The on-board unit includes at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data
communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
[0038] The OBU has the following purposes: 1. To automatically repetitively estimate the locomotive's position, using GPS, a crossing and waypoint database and locomotive tachometer inputs to determine whether it is approaching any level crossings, and if so, which level crossing. 2. To automatically provide early warning to RSU's at type 2 and 3 crossings, via radio data communications, that the locomotive is approaching.
3. To automatically provide early warning to any IVU's which are in the vicinity of type 1 crossings, via UHF audio communications, that the locomotive is approaching the crossing.
[0039] In the OBU, a GPS receiver repetitively estimates the locomotive's location. A distance/speed input (Tachometer) from within the locomotive is used to temporarily support location tracking if the GPS is offline.
[0040] Each OBU includes at least one and preferably a pair of Multitrax components to control operation of the OBU and to offer redundancy. Each Multitrax component is preferably a multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly or implements instructions based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly, based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
[0041 ] Each OBU preferably has a unique address or device identifier, allowing it to be identified within the system.
[0042] The OBU is preferably associated with a provider of information and/or stores information related to any one or more of the transport networks or vehicles within the system. The provision of information to the OBU may be through a wireless link or a physical device such as a removable data storage device may be used with upload external content to the OBU.
[0043] The RSU is essentially a multi-band, multi-protocol radio transceiver station which communicates with passing trains, as well as transmitting warning messages directly to road vehicles.
[0044] Each RSU has a unique address or device ID, allowing it to be identified within the system.
[0045] A processor within the RSU manipulates data and controls warning message transmissions.
[0046] Data is entered via a serial connection or GPRS network and stored in a solid state memory device. The solid state memory device can be of a removable type such as an SD Card.
[0047] Directional antennas are used to direct the UHF transmission of the warning message, an adjustable splitter/attenuator controls the distance of the transmission.
[0048] Power for the RSU can be supplied either from existing fixed infrastructure (if available) or from a battery source with solar recharge facility. An conventionally available power supply converter which conforms to the relevant rail standards will be used to connect fixed infrastructure power to the RSU power input.
[0049] Data may be transmitted from the RSU to vehicles via UHF to in vehicle units or via a Dedicated Short Range Communication (DSRC) transceiver. This data can be used by automotive computers. The DSRC data is not intended to be used as the primary means of notifying vehicle operator of dangerous situations due to the limitations of the current 5.9GHz DSRC system i.e. range and latency.
[0050] The IVU is a UHF radio receiver that is retrofitted between a vehicle stereo unit and the power/speaker cabling.
[0051 ] When the IVU receives a UHF warning message, it disconnects the signal received from the stereo to the speakers and directs the incoming warning message to the front speakers.
[0052] The IVU is designed to "fail to safe". If the power supply to the IVU is
interrupted/fails or the IVU fails, the stereo signal normally routed to the speakers is cut, thus notifying the vehicle operator of a problem.
[0053] During start up the IVU carries out a self-test by transmitting a small test signal to itself, if it does not confirm it is operating correctly the speakers will remain muted; thus notifying the vehicle's operator of the IVU's failure.
[0054] The IVU contains an internal linearly-polarised UHF antenna or based on installation, may be connected to an external antenna.
[0055] The IVU is able to operate from a 12-24VDG supply with a negative chassis only.
[0056] As it is considered that additional spin off benefits of this technology will be exercised; that is, its use with warning of the presence of emergency vehicles, roadside hazards etc; situations may arise where multiple messages are being broadcast to motorists
simultaneously. In this situation it would be necessary to determine the most important messages and ensure that the public receives the message with the highest priority.
[0057] An example of this would be a motorist approaching a rail level crossing and receiving a message that an ambulance was approaching. Although it is appropriate that the ambulance transmits its warning message, it may temporarily distract the driver and result in minimised attention to the level crossing. Should a train be approaching this level crossing, the warning of the highest priority would be determined that a potential for a collision with the train would take precedence. In this instance, the IVU would be able to make this determination and switch to the higher priority warning. The ambulance would also be notified of the train's presence.
[0058] A portable calibration unit will be needed to ensure that all components of the GRSS system are calibrated to ensure warning messages are received by IVU's in a timely manner. The PCU is designed to set an OBU and RSU's warning message power based upon physical installation location of the units and an IVU's receive sensitivity based upon in vehicle mounting. [0059] A System Control Centre will be required to coordinate data coming in and out of the GRSS system. This data includes updates to the crossing database, faults reported in the system and general operational logs. GRSS system data is sent via GPRS or via UHF, and the System Control Centre will monitor this data for error messages and faults. The System Control Centre will be responsible for keeping locomotive databases up-to-date and providing a means to enter new track information and marker data.
[0060] Within the OBU there will be multiple Master and Slave MultiTrax component. The OBU, upon power up, identifies which MultiTrax component will be the Master and which will be the Slave. In normal operation within the RSU, there will be a dedicated MultiTrax component for data and a dedicated MultiTrax component for warning message transmission. If one fails however, the other will assume both roles.
[0061 ] The OBU, once powered up, will be able to communicate and update the HMI display.
[0062] The OBU is able to monitor the health of its systems. Systems that are to be monitored include the GPS module, the memories and data storage and the MultiTrax component itself. The OBU is able to establish if a MultiTrax component has failed.
[0063] The RSU is able to monitor the health of the data MultiTrax component and the warning message MultiTrax component.
[0064] The OBU, upon monitoring the systems state, reports the system state to the HMI. If the system state has changed to an error state, the system stores this error to a log file. This error should also be transmitted back to the system control centre when able.
[0065] The OBU has Two (2) MultiTrax component, each with its own GPS. The OBU is to be able to read GPS data provided by the GPS modules.
[0066] The OBU is supplied a tachometer input from the locomotive. The OBU is to be able to interpret signals coming from the tachometer and convert these to speed and distance readings.
[0067] Within the OBU is high capacity memory storage which will contain a crossing database. The crossing database contains a list of every crossing and key marker position providing its GPS latitude and longitude coordinates. The OBU shall be able to search through this database and be able to locate the next key marker position or crossing based on the GPS coordinates provided by the GPS. [0068] The OBU through the use of Tachometer input and GPS input, shall be able to track its current speed.
[0069] Using the crossing database and the current GPS coordinates of the locomotive, the OBU will be able to calculate the distance and time to the next crossing that it will need to activate.
[0070] The OBU will be able to activate a local warning message and be able to transmit this over UHF for a provided amount of activation time. The activation time will be related to the amount of time that the locomotive is approaching the crossing and is over the crossing.
[0071 ] The OBU will not only be required to activate the local UHF warning message but ensure that it is activated at the correct time before approaching the crossing.
[0072] A locomotive may perform a number of actions when approaching a crossing. As an example, there may be a station just prior to the level crossing at which the locomotive may become stationary. The OBU shall continue to transmit a warning message whilst it is within a defined distance to the 'crossing. The warning message will only deactivate when the train is beyond the crossing.
[0073] The OBU will be able to self-assess its' Local UHF transmissions and monitor if they are being transmitted.
[0074] The OBU, when within a defined communication range of an RSU, will establish a connection with an RSU unit to begin activation of its local UHF warning message.
[0075] A locomotive OBU should be able to establish a communication link with an RSU at a greater distance than 50 seconds from the crossing when the locomotive is moving at 100kph.
[0076] Once a communication link has been established, the OBU shall be able to calculate and transmit a start activation time and activation timeout to the RSU.
[0077] Once the locomotive has established a communication link with the RSU and updated its Start Activation Timer and Stop Activation Timer the OBU shall disconnect from the RSU. The Connection disconnection routine may continue multiple times during the locomotives passing of the level crossing.
[0078] Once the locomotive has passed beyond the Type 1 level crossing, the OBU shall deactivate its local UHF Warning Message. [0079] Once the locomotive has passed beyond the Type 2 or Type 3 level crossing, the OBU shall monitor that the RSU has deactivated its Local Warning Message.
[0080] The OBU will be required to monitor and activate multiple crossings.
[0081 ] OBU activates Local UHF Warning Message on the same channel frequency until clear of both Type 1 Crossings.
[0082] Type 2 Crossing, if in communication range, is sent an Activation message. OBU waits for acknowledgement timeout. OBU activates Local Warning Message for Type 1 Crossing for Warning Message Time. OBU again communicates with Type 2 crossing at completion of local Warning Message and waits a defined acknowledgment timeout (less than 1 second). The process is repeated until clear of crossing.
[0083] OBU sequentially connects and disconnects from each Type 2 crossing, updating the Activation Timeout time.
[0084] The OBU shall incorporate within its UHF communication protocol a Carrier Sense Multiple Access/Collision Avoidance algorithm. The OBU shall first monitor the channel activity before proceeding with a Data Transmission.
[0085] The RSU contains two MultiTrax, one which will be used for data transmission and one which will be used for UHF Warning Message transmission. The RSU will select the role of warning message transmission by its configuration data. The Warning Message MultiTrax may be connected to an Attenuator Splitter board.
[0086] The RSU shall only activate a warning message system when it has been told to do so by an OBU or another RSU. The RSU is not to provide false activations.
[0087] The RSU shall only activate when its Start Activation Timeout has expired. RSU activation shall not occur until this time. .
[0088] The RSU shall be able to monitor its UHF Warning Message power being transmitted and determine if a transmission has occurred.
[0089] The RSU will only de-activate its warning message when the activation timeout reaches zero.
[0090] The RSU shall be able to transmit a warning message in a desired direction and distance. The RSU shall be able to minimise nuisance activations of Pixie In- Vehicle Units where activation is not required.
[0091 ] The RSU shall be able to communicate to multiple OBU units by being able to connect and disconnect from each OBU. Activation times for the RSU will take the worst case scenario (earliest activation time start and latest activation time end)
[0092] The RSU, for Type 3 Level Crossings, is connected to railway infrastructure. The RSU, when required, is to be'activated by the trackside infrastructure.
[0093] The RSU has the capability of controlling trackside infrastructure if required.
Appropriate SIL rating is required for this operation.
[0094] The RSU shall incorporate a Carrier Sense Multiple Access/Collision Avoidance algorithm. The RSU shall first monitor the channel activity before proceeding with a Data Transmission.
[0095] When the IVU receives a UHF Warning Message on a particular UHF channel and CTCSS tone code it will cut the warning message in over the speakers within the vehicle.
[0096] If the RSSI Level of a UHF Warning Message is below a defined RSSI level, the IVU shall switch the in road vehicle speakers back to the road vehicles head unit signal rather than the UHF Warning Message signal.
[0097] The IVU, after receiving a UHF Warning Message, shall only perform 3 cycles of the Warning Message before switching back to the road vehicles head unit to limit the annoyance factor.
[0098] The IVU, based on a Warning Message Priority System, shall activate the warning message of highest priority. The Warning Message must finalise its playback before a higher priority message is played.
[0099] There will also be a variety of OBU Failure Modes including:
■ Master Failed, Slave OK - Upon OBU Master MultiTrax unit failing, the OBU Slave MultiTrax must disable Master MultiTrax unit and perform all tasks of the Master. Failure is logged and reported. Slave MultiTrax reports to HMI of Master MultiTrax failure. Slave Unit becomes Master Unit.
■ Slave Failed, Master OK - Upon the OBU Slave MultiTrax unit failing, the OBU Master MultiTrax will disable the Slave MultiTrax and report the fault. Master reports to HMI of Slave MultiTrax failure.
■ Master Fail, OBU Slave Fail - Upon both the Master MultiTrax and Slave MultiTrax units failing, the HMI will show error screen to Locomotive operator.
■ Failed To Receive GPS Signal On Master Unit, Slave OK - OBU upon detecting a failed GPS Signal shall request Valid GPS Data from Slave Unit.
■ Failed To Receive GPS Signal On Master and Slave Unit - OBU provides warning output on HMI that GPS has failed. Locomotive will track progress via Tacho input only.
■ Failed To Receive Tacho Signal on Master - OBU shall request Valid Tacho data from Slave Unit.
■ Failed To Receive Tacho Signal on Master and Slave - OBU shall revert back to GPS only coordinates. OBU provides HMI with warning the Tacho has failed. Error is logged.
■ Failed To Receive GPS and Tacho Signal on Master and Slave - OBU shall provide warning message to HMI that GPS and Tacho have failed.
■ Database Crossing Point Corrupted on Master, Slave OK - The OBU will, if one database crossing coordinate is corrupted, will communicate with the Slave unit for its Database data.
■ Database Point Corrupted on Master and Slave - The OBU will, if both databases are corrupted, send a warning message to the HMI and log the fault. The OBU will then move to the next location in the database.
■ UHF Transmitter Antenna Damaged - The OBU, whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason. The OBU must recognise a warning message signal is not being transmitted and must activate the redundant MultiTrax.
■ Failed to receive an RSU Acknowledge - The OBU will attempt to establish
communication with a crossing at a distance equal to the current speed of the locomotive reaching the crossing in 30 seconds. If the OBU has not received an acknowledgment from the RSU at 22 seconds from the crossing, the OBU shall activate its Type 1 Local UHF Warning Message. The Local UHF Warning Message shall be transmitted on a different frequency to that of the RSU Warning Message to ensure that, if Type 2/3 activation has occurred, the locomotive will not interfere with the RSU Warning Message.
100] There will also be a variety of RSU Failure Modes including: • Master Failed, Slave OK - Upon RSU Master MultiTrax unit failing, the RSU is considered to have failed. OBU will log the RSU fault.
■ Slave Failed, Master OK - Upon the RSU Slave MultiTrax unit failing, the RSU is
considered to have failed. OBU will log the RSU fault.
■ Master Fail, Slave Fail - Upon both the Master MultiTrax and Slave MultiTrax units failing, the RSU is considered failed and will not be able to communicate to an OBU. OBU will log the RSU fault.
■ UHF Transmitter Antenna Damaged - The RSU, whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason. The RSU must recognise a warning message signal is not being transmitted and must log the fault.
■ Detects Failure of Railway Infrastructure for Type 3 Crossing - The RSU, upon detecting a failure of Railway Infrastructure such as boom gates or flashing lights shall report failure back to an approaching OBU and log the fault.
[00101 ] The IVU will fail to safe when an electronic or mechanical failure occurs. If the IVU fails, the radio front speakers will fail which will bring the failure to the attention of the vehicle driver.
[00102] The present invention may also include a Personal Device Unit (PDU). According to one particularly preferred form, the PDU is a UHF radio receiver which can be integrated into earphone sets or directly into personal devices such as smartphones, mobile phones, tablets, MP3 players and the like or retrofit to such devices which include one or more speakers. This is particularly useful for use in pedestrian circumstances where pedestrians are placed in high risk areas such as pedestrian level crossings.
[00103] According to a particularly preferred embodiment, when the PDU receives a warning message, it switches off the signal from the master unit to the speakers of the one or more speakers of the personal devices, and directs the incoming message to the speaker(s) of the personal device or via the headphones.
[00104] The PDU also has the ability to receive data messages via UHF, which it passes on to the personal device's internal computer via a preferred serial cable connection.
[00105] If the power supply to the PDU is interrupted/fails, the mobile device's speakers are muted, thus notifying the user of a problem. The system in the mobile device could be configured to use power directly from the personal device's battery, so operation could not be interfered with by the user. This is particularly useful when applied to young users as it would work if the device was turned off deliberately through a low state of charge.
[00106] During start up the PDU preferably carries out a self-test by transmitting a small test signal to itself. If the PDU does not confirm that it is operating correctly, the speakers of the personal device will remain muted; thus notifying the user of the PDU's failure.
[00107] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.
[00108] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.
BRIEF DESCRIPTION OF DRAWINGS
[00109] Various embodiments of the invention will be described with reference to the following drawings, in which:
[00110] Figure 1 is a schematic view of a particularly preferred embodiment of the invention applied to a type 1 , low risk - passive level crossing.
[00111] Figure 2 is a schematic view of a particularly preferred embodiment of the invention applied to a type 2, medium risk - passive crossing.
[00112] Figure 3 is a schematic view of a particularly preferred embodiment of the invention applied to a type 3, high risk - active crossing.
[00113] Figure 4 is . a schematic view of a preferred embodiment of the system of the present invention and the communications interfaces between the different components of the system.
[00114] Figure 5 is a pictorial representation of an on board unit human interface according to a preferred embodiment of the present invention.
[00115] Figure 6 is a schematic view of the internal components and external interfaces of a Multitrax component according to a particularly preferred embodiment of the present invention.
[00116] Figure 7 is a schematic view of the UHF transceiver of the preferred embodiment contained within the Multitrax component of the preferred embodiment. [00117] Figure 8 is a schematic illustration showing the location of the in vehicle unit in relation to the vehicle stereo, speakers and power supply according to a preferred embodiment.
[00118] Figure 9 is a schematic illustration of the internal components of the in vehicle unit according to a preferred embodiment.
[00119] Figure 10 is a flowchart illustrating the power-on self-test (POST) for the in vehicle unit according to a preferred embodiment of the invention.
[00120] Figure 1 1 is a flowchart illustrating the operation of the IVU in idle/scanning mode according to a preferred embodiment of the invention.
[00121] Figure 12 is a flowchart illustrating the operation of the IVU in receiving signal mode for the in vehicle unit according to a preferred embodiment of the invention.
[00122] Figure 13 is a flowchart illustrating the operation of the IVU in calibrating mode for the in vehicle unit according to a preferred embodiment of the invention.
[00123] Figure 14 is an illustration of the hierarchical structure of the software operating on the IVU with arrows indicating the direction of function calling according to a preferred embodiment.
[00124] Figure 15 is a schematic illustration of the IVU communications baseband spectrum according to a preferred embodiment.
[00125] Figure 16 is a schematic illustration of the IVU communications baseband spectrum for an FSK data transmission according to a preferred embodiment.
[00126] Figure 17 is a schematic illustration of the IVU transmission sequence (not to scale) according to a preferred embodiment.
[00127] Figure 18 is a schematic illustration of the IVU transmission sequence for a repeated message (not to scale) according to a preferred embodiment.
[00128] Figure 19 is a schematic illustration of the IVU calibration transmission sequence (not to scale) according to a preferred embodiment.
[00129] Figure 20 is a schematic illustration of the IVU transmission sequence for FSK data transmission (not to scale) according to a preferred embodiment. [00130] Figure 21 is a schematic illustration of the preferred radiation coverage of adjacent roads provided by RSU antennas at type 2 and 3 crossings according to a preferred embodiment.
[00131 ] Figure 22 is a schematic illustration of the preferred radiation coverage of adjacent roads provided by RSU antennas at type 2 and 3 crossings where more than two antenna's are required according to a preferred embodiment.
[00132] Figure 23 is a schematic illustration of the preferred radiation coverage of adjacent roads provided by OBU antennas at type 1 crossings according to a preferred embodiment.
[00133] Figure 24 is a schematic illustration of the preferred OBU transmission power calculation according to a preferred embodiment.
DESCRIPTION OF EMBODIMENTS
[00134] According to a particularly preferred embodiment, a radio break in system is provided which incorporates a variety of individual apparatus operating together to form an integrated system.
[00135] Figures 1 to 3 are pictorial representations of the railway crossings in relation to which the present invention is used. The crossings have been categorised into three types:
[00136] A Type 1 , Low Risk - Passive Crossing illustrated in Figure 1 - Transmitter fitted to the locomotive of the train and controlled via a GPS switching system which activates when a train is nearing a crossing.
[00137] A Type 2, Medium Risk - Passive Crossing with RSU fitted illustrated in Figure 2. A battery/mains powered trackside transmitter is controlled/activated by the approaching locomotives On-board GPS system. Directional antennas ensure that messages are transmitted to relevant vehicles only; minimising the nuisance aspect. The controller checks to see that the transmitter is activating appropriately, and fails to safe by activating the train's transmitter in the event of a malfunction as per protections offered in type 1 system.
[00138] A Type 3, High Risk - Active Crossing with RSU fitted illustrated in Figure 3. Trackside transmitter is controlled by the existing active infrastructure. Directional antennas ensure that messages are transmitted to relevant vehicles only minimising the nuisance aspect. On board Controller monitors the operational status of the active crossing's warning system, and fails to safe by activating the train's transmitter in the event of a malfunction as per protections offered in type 1 system. The system of the present invention utilises a UHF data link from train to fixed infrastructure. A UHF audio transmission is sent from either the train or fixed infrastructure to the road vehicle's In Vehicle Unit.
[00139] The apparatus of the present invention is a distributed network of mobile and fixed radio transceivers and receivers, centred on rail networks and road vehicles. The system includes of a GPS control system on board the locomotive. The system activates a verbal warning message either directly to vehicles or to vehicles via the road crossing infrastructure.
[00140] The warning message is transmitted directly to the vehicles' existing stereo speaker system, regardless of the stereo's status; radio, on, off, CD, hands free Bluetooth etc. The warning message is transmitted directly to the vehicles' existing stereo speaker system, regardless of the stereo's status; radio, on, off, CD, hands free Bluetooth etc.
[00141 ] Illustrated in Figure 4 is a system communications overview diagram.
[00142] The GRSS system consists of several types of devices:
■ A locomotive on-board unit (OBU).
■ A roadside unit (RSU) at the road rail crossing.
■ An in vehicle unit (IVU) installed in road vehicles.
■ A portable calibration unit (PCU).
[00143] Each component interacts to the other components of the system through well- defined interfaces, to facilitate future flexibility in the design and implementations of the components themselves. These interfaces are illustrated in Figure 4 and are described in more detail below.
[00144] The OBU is an embedded computer system incorporating a UHF transceiver and GPS receiver, which tracks the locomotive's location on the rail network and controls the transmission of warning messages to road vehicles, either directly through its local UHF transmitter (Type 1 crossing), or via road-side units (Type 2 and 3 crossings).
[00145] Two cooperative microprocessors within the OBU control its operation offering redundancy in the event of hardware failure; both are contained within a specific portion of the OBU described below. [00146] The microprocessors within the OBU track the locomotives location, analyse future crossings, manipulate data, provide data transmission to RSU's and control warning message transmissions.
[00147] The OBU unit has dual power supplies, processors, GPS modules & antennas, GPRS modules & Antennas, UHF transceivers & Antennas in the event of a localised hardware failure.
[00148] Each OBU has a unique address or device ID, allowing it to be identified within the system.
[00149] Configuration data and track databases are entered via a serial connection or GPRS network and stored in a solid state memory device. (Data may be loaded directly onto large memory device at manufacture time). The solid state memory device is of a removable storage type so that databases may be uploaded external to the unit.
[00150] Data which is uploaded to the OBU from GPRS or serially,, and stored, includes:
Track details including:
a. Location of crossings (GPS Coordinates)
b. Location of GPS signal loss (tunnels etc)
c. Network address/Device ID's of RSU's
d. Type of crossing
e. Track distance between crossings
f. UHF Communication frequencies
g. CTCSS tone codes
[00151 ] Other data required: 1. Locomotive data (length, type etc)
2. Track zone
3. Locomotive route
4. OBU specific configuration data
[00152] Power for the OBU is supplied from the locomotive, via twin rail certified supplies to reduce the risk of power failure.
[00153] A human interface (HMI) to the OBU is achieved by the use of an LCD touch-screen display and/or audio speaker and/or indication LED's. Once configured at the beginning of a journey, under normal operation, the locomotive operator is not required to interact with the OBU. Unless there is a malfunction in some part of the system, the OBU shall be able to perform all of its functions automatically. The driver will be able to quickly confirm at any time that the OBU is functioning correctly by glancing at the LCD display, which will provide visual status information (see Figure 5). If however, the LCD display is not required, the OBU will be able to achieve all of its functions without it being attached. Any failure of the OBU shall be signified by indication LED's on the OBU. Failures shall also be reported via the OBU's GSM hardware.
[00154] The OBU of the preferred embodiment includes: 1. 1 x HMI LCD Screen (Optional)
2. 1 x Audio Speaker (Optional)
3. 2 x MultiTrax component
4. 2 x Power Supply units
5. 2 x Signal Isolators
6. 2 x UHF Circularly Polarized Low Profile Antennas (See "GRSS Antenna System Specification")
7. 2 x GSM Antennas (May be combined with GPS antennas in single package)
8. 2 x GPS Antennas . 9. 1 x Enclosure
[00155] An OBU is installed in each locomotive in the rail network in which the GRSS is being used. The unit may be enclosed in one or more physical enclosures - e.g. the HMI user interface may be separate from the OBU and power supply units, to minimise clutter in the locomotive cabin. The UHF, GPRS and GPS antennas are all to be mounted externally on the locomotive, in a location such as the cabin's rooftop.
[00156] The power supply units convert electrical power from the locomotive to a form suitable for use by the rest of the OBU system. The power supply used must be suitable for rail operation and shall output 12V/24V DC @ 5A/2.5A continuous power to supply the rest of the OBU's components. The power supply must conform to the relevant rail standards. As the voltage and frequency standards for electrical power on locomotives varies widely, power supply units will be selected as required.
[00157] The RSU (mains powered) of the preferred embodiment, includes: 1. 2 x MultiTrax component
2. 1 x Power Supply units
3. 1 x DSRC Transceiver (Optional)
4. 1 x Omni Directional UHF Data Communication Antenna
5. Up to 4 Directional UHF Antennas determined by road infrastructure crossing
6. 1 x UHF Splitter/Attenuator
7. 1 x GSM Antennas
8. 1 x DSRC Antenna
9. 1 x Enclosure 1
The RSU (solar powered) of the preferred embodiment, includes: 1. 2 x MultiTrax component
2. 1 x Solar Panel
3. l x Battery Box f
4. 1 x DSRC Transceiver (Optional)
5. lx Omni Directional UHF Data Communication Antenna
6. Up to 4 Directional UHF Antennas determined by road infrastructure at crossing
7. 1 x UHF Splitter/Attenuator
8. 1 x GSM Antennas
9. 1 x DSRC Antenna
10. 2 x Enclosures
[00159] The IVU is a UHF radio receiver that is retrofitted between a vehicle stereo unit and the power/speaker cabling.
[00160] When the IVU receives a UHF warning message, it disconnects the signal received from the stereo to the speakers and directs the incoming warning message to the front speakers.
[00161 ] The IVU is designed to "fail to safe". If the power supply to the IVU is
interrupted/fails or the TVU fails, the stereo signal normally routed to the speakers is cut, thus notifying the vehicle operator of a problem.
[00162] During start up the IVU carries out a self-test by transmitting a small test signal to itself, if it does not confirm it is operating correctly the speakers will remain muted; thus notifying the vehicle's operator of the IVU's failure.
[00163] The IVU contains an internal linearly-polarised UHF antenna or based on installation, may be connected to an external antenna.
[00164] The IVU is able to operate from a 12-24VDC supply with a negative chassis only.
[00165] A portable calibration unit will be needed to ensure that all components of the GRSS system are calibrated to ensure warning messages are received by IVU's in a timely manner. The PCU is designed to set an OBU and RSU's warning message power based upon physical installation location of the units and an IVU's receive sensitivity based upon in vehicle mounting.
[00166] A System Control Centre will be required to coordinate data coming in and out of the GRSS system. This data includes updates to the crossing database, faults reported in the system and general operational logs. GRSS system data is sent via GPRS or via UHF, and the System Control Centre will monitor this data for error messages and faults. The System Control Centre will be responsible for keeping locomotive databases up-to-date and providing a means to enter new track information and marker data.
[00167] Due to the nature of the system and the components operating therein, a number of communications interfaces are defined. These include:
OB U to RSU Data Link
This is a bidirectional peer-to-peer radio data communications interface. RSU to RSU Data Link
The application may be required for a "Mesh Network" of RSU's to be utilised for the transmission of data throughout the GRSS system and for the mass synchronisation of warning messages, for example during emergency situations such as bush fires, storms etc. Just as OBU's and RSU's may communicate together, two RSU's may communicate data.
Mesh Networked communication may be necessary for locations where the GSM network may not be available or as a redundancy to the GSM network.
IVU Receiver UHF Communications
This one-way radio communications interface is an audio FM signal employing a continuous tone-coded squelch system (CTCSS). CTCSS ensures that the IVU receiver only relays audio from the GRSS system, instead of relaying all signals received on its frequency. The carrier frequency may be from 400MHz to 470MHz. The modulating signal is literally a human-perceivable (e.g. voice and/or siren sounds) audio signal in addition to the sub-audio CTCSS signal. This interface is described in detail in the "Pixie IVU Communications Specification" document. The IVU only receives communications in this interface, it does not transmit.
Receive sensitivity and other specifications may be found in the relevant Design Specification document.
System Control Centre Data Link
This bidirectional digital communications protocol is carried over the TCP/IP protocol via GPRS and is primarily used for updating the rail network crossings maps within each OBU, as well as notifying the system control centre of system failures.
USB Link for Track Network Data
This bidirectional digital communications protocol operates over a direct serial link between a PC and an OBU/RSU, and is primarily used as an initial or alternative method to update rail network crossings maps within the OBU and configuration data in the OBU and RSU.
[00168] There are also a number of possible external interfaces for the apparatus. These include:
GPS is repetitively used by each OBU as the primary means to ascertain its position within the rail network.
A GPRS network and the internet will be used to carry data communications between a control centre and OBU's and RSU's. A GPRS interface is employed within both the RSU and OBU with a higher-level protocol used to communicate between central control and each OBU and RSU.
An electrical signal from either a dedicated speed/distance sensor within the locomotive's mechanical system, or the locomotive's control system is provided to the OBU.
The IVU can switch off up to 6 speakers channels, 2 of which (front speakers) can relay warning audio signals. The IVU is able to tolerate minimum speaker impedances of 3.5 Ohms. Switches are able to pass up to 250V RMS (with respect to chassis) and 5A of current when not interrupting the normal speaker circuits. As is usually the case - front speakers must be wired to be electrically floating with respect to chassis potential. Front speakers must be rated to 10W RMS.
The IVU can be powered from a 12V-24V DC supply with a negative chassis. As the IVU draws non-negligible current, it is advised that it is wired to only be supplied with power when the vehicle is occupied (e.g. when ignition key in "accessories" position), to prevent draining of batteries. During operation, the IVU may draw a maximum of 5A of current, and so should be fused appropriately.
The RSU is capable of switching up to 1 OA and 250 VAC, on 8 external relays to provide control of warning signals such as flashing lights and alarms. The RSU has 8 Digital outputs, 8 Digital Inputs, 2 Analogue Inputs, 2 Analogue Outputs, Audio output as well as a serial interface (RS485) to allow remote control and monitoring of existing crossing infrastructure.
Mains-powered RSU's require a 12VDC 3 Amp power input, which is required to be 99% uninterrupted, as undesirable backup provisions exist such as direct train to IVU transmission.
[00169] Within the OBU there will be multiple Master and Slave MultiTrax component. The OBU, upon power up, identifies which MultiTrax component will be the Master and which will be the Slave. In normal operation within the RSU, there will be a dedicated MultiTrax component for data and a dedicated MultiTrax component for warning message transmission. If one fails however, the other will assume both roles.
[00170] The OBU, once powered up, will be able to communicate and update the HMI display.
[00171 ] The OBU is able to monitor the health of its systems. Systems that are to be monitored include the GPS module, the memories and data storage and the MultiTrax component itself. The OBU is able to establish if a MultiTrax component has failed.
[00172] The RSU is able to monitor the health of the data MultiTrax component and the warning message MultiTrax component.
[00173] The OBU, upon monitoring the systems state, reports the system state to the HMI. If the system state has changed to an error state, the system stores this error to a log file. This error should also be transmitted back to the system control centre when able. [00174] The OBU has Two (2) MultiTrax components, each with its own GPS. The OBU is to be able to read GPS data provided by the GPS modules.
[00175] The OBU is supplied a tachometer input from the locomotive. The OBU is to be able to interpret signals coming from the tachometer and convert these to speed and distance readings.
[00176] Within the OBU is high capacity memory storage which will contain a crossing database. The crossing database contains a list of every crossing and key marker position providing its GPS latitude and longitude coordinates. The OBU shall be able to search through this database and be able to locate the next key marker position or crossing based on the GPS coordinates provided by the GPS.
[00177] The OBU through the use of Tachometer input and GPS input, shall be able to track its current speed.
[00178] Using the crossing database and the current GPS coordinates of the locomotive, the OBU will be able to calculate the distance and time to the next crossing that it will need to activate.
[00179] The OBU will be able to activate a local warning message and be able to transmit this over UHF for a provided amount of activation time. The activation time will be related to the amount of time that the locomotive is approaching the crossing and is over the crossing.
[00180] The OBU will not only be required to activate the local UHF warning message but ensure that it is activated at the correct time before approaching the crossing.
[00181 ] A locomotive may perform a number of actions when approaching a crossing. As an example, there may be a station just prior to the level crossing at which the locomotive may become stationary. The OBU shall continue to transmit a warning message whilst it is within a defined distance to the crossing. The warning message will only deactivate when the train is beyond the crossing.
[00182] The OBU will be able to self-assess its' Local UHF transmissions and monitor if they are being transmitted.
[00183] The OBU, when within a defined communication range of an RSU, will establish a connection with an RSU unit to begin activation of its local UHF warning message.
[00184] A locomotive OBU should be able to establish a communication link with an RSU at a greater distance than 50 seconds from the crossing when the locomotive is moving at 100kph.
[00185] Once a communication link has been established, the OBU shall be able to calculate and transmit a start activation time and activation timeout to the RSU.
[00186] Once the locomotive has established a communication link with.the RSU and updated its Start Activation Timer and Stop Activation Timer the OBU shall disconnect from the RSU. The Connection disconnection routine may continue multiple times during the
locomotives passing of the level crossing.
[00187] Once the locomotive has passed beyond the Type 1 level crossing, the OBU shall deactivate its local UHF Warning Message.
[00188] Once the locomotive has passed beyond the Type 2 or Type 3 level crossing, the OBU shall monitor that the RSU has deactivated its Local Warning Message.
[00189] The OBU will be required to monitor and activate multiple crossings.
[00190] OBU activates Local UHF Warning Message on the same channel frequency until clear of both Type 1 Crossings.
[00191 ] Type 2 Crossing, if in communication range, is sent an Activation message. OBU waits for acknowledgement timeout. OBU activates Local Warning Message for Type 1 Crossing for Warning Message Time. OBU again communicates with Type 2 crossing at completion of local Warning Message and waits a defined acknowledgment timeout (less than 1 second). The process is repeated until clear of crossing.
[00192] OBU sequentially connects and disconnects from each Type 2 crossing, updating the Activation Timeout time.
[00193] The OBU shall incorporate within its UHF communication protocol a Carrier Sense Multiple Access/Collision Avoidance algorithm. The OBU shall first monitor the channel activity before proceeding with a Data Transmission.
[00194] The RSU contains two MultiTrax components, one which will be used for data transmission and one which will be used for UHF Warning Message transmission. The RSU will select the role of warning message transmission by its configuration data. The Warning Message MultiTrax component may be connected to an Attenuator Splitter board. [00195J The RSU shall only activate a warning message system when it has been told to do so by an OBU or another RSU. The RSU is not to provide false activations.
[00196] The RSU shall only activate when its Start Activation Timeout has expired. RSU activation shall not occur until this time.
[00197] The RSU shall be able to monitor its UHF Warning Message power being transmitted and determine if a transmission has occurred.
[00198] The RSU will only de-activate its warning message when the activation timeout reaches zero.
[00199] The RSU shall be able to transmit a warning message in a desired direction and distance. The RSU shall be able to minimise nuisance activations of In- Vehicle Units where activation is not required.
[00200] The RSU shall be able to communicate to multiple OBU units by being able to connect and disconnect from each OBU. Activation times for the RSU will take the worst case scenario (earliest activation time start and latest activation time end).
[00201 ] The RSU, for Type 3 Level Crossings, is connected to railway infrastructure. The RSU, when required, is to be activated by the trackside infrastructure.
[00202] The RSU has the capability of controlling trackside infrastructure if required.
Appropriate SIL rating is required for this operation.
[00203] The RSU shall incorporate a Carrier Sense Multiple Access/Collision Avoidance algorithm. The RSU shall first monitor the channel activity before proceeding with a Data Transmission.
[00204] When the IVU receives a UHF Warning Message on a particular UHF channel and CTCSS tone code it will cut the warning message in over the speakers within the vehicle.
[00205] If the RSSI Level of a UHF Warning Message is below a defined RSSI level, the IVU shall switch the in road vehicle speakers back to the road vehicles head unit signal rather than the UHF Warning Message signal.
[00206] The IVU, after receiving a UHF Warning Message, shall only perform 3 cycles of the Warning Message before switching back to the road vehicles head unit to limit the annoyance factor.
[00207] The IVU, based on a Warning Message Priority System, shall activate the warning message of highest priority. The Warning Message must finalise its playback before a higher priority message is played.
[00208] There will also be a variety of OBU Failure Modes including:
■ Master Failed, Slave OK - Upon OBU Master MultiTrax component failing, the OBU Slave MultiTrax component must disable Master MultiTrax component and perform all tasks of the Master. Failure is logged and reported. Slave MultiTrax component reports to HMI of Master MultiTrax component failure. Slave Unit becomes Master Unit.
■ Slave Failed, Master OK - Upon the OBU Slave MultiTrax component failing, the OBU Master MultiTrax component will disable the Slave MultiTrax component and report the fault. Master reports to HMI of Slave MultiTrax component failure.
■ Master Fail, OBU Slave Fail - Upon both the Master MultiTrax component and Slave MultiTrax component failing, the HMI will show error screen to Locomotive operator.
■ Failed To Receive GPS Signal On Master Unit, Slave OK - OBU upon detecting a failed GPS Signal shall request Valid GPS Data from Slave Unit.
■ Failed To Receive GPS Signal On Master and Slave Unit - OBU provides warning output on HMI that GPS has failed^ Locomotive will track progress via Tacho input only.
■ Failed To Receive Tacho Signal on Master - OBU shall request Valid Tacho data from Slave Unit.
■ Failed To Receive Tacho Signal on Master and Slave - OBU shall revert back to GPS only coordinates. OBU provides HMI with warning the Tacho has failed. Error is logged.
■ Failed To Receive GPS and Tacho Signal on Master and Slave - OBU shall provide warning message to HMI that GPS and Tacho have failed.
■ Database Crossing Point Corrupted on Master, Slave OK - The OBU will, if one database crossing coordinate is corrupted, will communicate with the Slave unit for its Database data.
■ Database Point Corrupted on Master and Slave - The OBU will, if both databases are corrupted, send a warning message to the HMI and log the fault. The OBU will then move to the next location in the database.
■ UHF Transmitter Antenna Damaged - The OBU, whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason. The OBU must recognise a warning message signal is not being transmitted and must activate the redundant MultiTrax component.
■ Failed to receive an RSU Acknowledge - The OBU will attempt to establish
communication with a crossing at a distance equal to the current speed of the locomotive reaching the crossing in 30 seconds. If the OBU has not received an acknowledgment from the RSU at 22 seconds from the crossing, the OBU shall activate its Type 1 Local UHF Warning Message. The Local UHF Warning Message shall be transmitted on a different frequency to that of the RSU Warning Message to ensure that, if Type 2/3 activation has occurred, the locomotive will not interfere with the RSU Warning Message.
[00209] There will also be a variety of RSU Failure Modes including:
■ Master Failed, Slave OK - Upon RSU Master MultiTrax component failing, the RSU is considered to have failed. OBU will log the RSU fault.
■ Slave Failed, Master OK - Upon the RSU Slave MultiTrax component failing, the RSU is considered to have failed. OBU will log the RSU fault.
■ Master Fail, Slave Fail - Upon both the Master MultiTrax component and Slave
MultiTrax component failing, the RSU is considered failed and will not be able to communicate to an OBU. OBU will log the RSU fault.
■ UHF Transmitter Antenna Damaged - The RSU, whilst monitoring transmit power, should be able to determine that an Antenna has been damaged or a signal is not being transmitted for some other reason. The RSU must recognise a warning message signal is not being transmitted and must log the fault.
■ Detects Failure of Railway Infrastructure for Type 3 Crossing - The RSU, upon detecting a failure of Railway Infrastructure such as boom gates or flashing lights shall report failure back to an approaching OBU and log the fault.
[00210] The IVU will fail to safe when an electronic or mechanical failure occurs. If the IVU fails, the radio front speakers will fail which will bring the failure to the attention of the vehicle driver.
[0021 1 ] In order to further illustrate the system of the present invention, a number of use cases are provided as examples of operation as follows:
Use Case 1 - Type 1 Crossing
Sequence of events: 1. A train approaches a defined level crossing.
2. OBU (on train) receives GPS signals and determines that it is within time x of entering a level crossing.
3. OBU begins transmitting warning audio-modulated UHF signal.
4. OBU detects that it is transmitting warning signal OK and continues transmission of signal.
5. IVU in passing road vehicle receives Pixie signal and relays audio warning message to speakers.
6. Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
7. Train proceeds through the level crossing, crossing the road without colliding with road vehicle.
8. OBU receives GPS signals and determines that it has finished crossing the road.
9. OBU stops transmission of the warning message.
Use Case 2 - Type 2 Crossing
Sequence of events:
1. A train approaches a defined level crossing.
2. OBU (on train) receives GPS signals and determines that it is within time x of entering a level crossing.
3. OBU connects to RSU via frequency and ID data stored in the crossings database located on the OBU.
4. RSU acknowledges connection request.
5. OBU sends warning command to RSU with timeout long enough to allow it to cross the road at its current speed.
6. RSU begins transmitting warning audio-modulated (IVU) UHF signal.
7. RSU detects that it is transmitting warning signal OK.
8. RSU responds to OBU that it is transmitting IVU signal OK. OBU disconnects from RSU. 9. IVU in passing road vehicle receives signal and relays audio warning message to speakers. 10. Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
1 1. Train crosses road without colliding with road vehicle. OBU is cycling through a connection and disconnection routine, checking that the RSU is still transmitting and length of time the transmission will continue to operate. 12. Train proceeds beyond the crossing and the OBU discontinues connection routine.
13. RSU times out warning period and stops transmitting.
Use Case 3 - Type 3 Crossing
Sequence of events:
1. A train approaches a defined level crossing.
2. OBU (on train) receives GPS signals and determines that it is within time x of crossing. 3. OBU connects to RSU via frequency and ID data stored in the crossings database located on the OBU.
4. RSU acknowledges connection request.
5. OBU sends warn command to RSU with timeout long enough to allow it to cross the road at its current speed.
6. RSU begins transmitting warning audio-modulated UHF signal.
7. RSU detects that it is transmitting warning signal OK.
8. RSU switches-on traditional signals installed (e.g. boom gates, flashing lights, bells). 9. RSU responds to OBU that it is transmitting signal OK.
10. IVU in passing road vehicle receives signal and relays audio warning message to speakers. 1 1. Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
12. Train crosses road without colliding with road vehicle. OBU is cycling through a connection and disconnection routine, checking that the RSU is still transmitting and length of time the transmission will continue to operate
13. Train proceeds beyond the crossing and the OBU discontinues connection routine.
14. RSU times out warning period and stops transmitting.
Use case 4 - Type 2 or 3 crossing complete RSU failure
Sequence of Events
1. A train approaches a defined level crossing.
2. OBU (on train) receives GPS signals and determines that it is within time x of crossing. 3. OBU attempts to connect to RSU via frequency and ID data stored in the crossings database located on the OBU.
4. OBU verifies that it is transmitting radio data signal using redundant MultiTrax component and UHF antenna. 5. OBU fails to receive acknowledgement from RSU within timeout period.
6. OBU stores failure notification in solid state memory to pass on to control centre when within GPRS range.
7. OBU begins transmitting warning audio-modulated UHF signal.
8. OBU detects that it is transmitting warning signal OK.
9. IVU in passing road vehicle receives signal and relays audio warning message to speakers. 10. Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
1 1. Train crosses road without colliding with road vehicle.
12. OBU receives GPS signals and determines that it has finished crossing the road.
13. OBU stops transmitting.
14. Next time in range, OBU connects to control centre via GPRS.
15. OBU notifies control centre of crossing failure.
Use case 5 - Type 2 or 3 RSU failure to transmit IVU signal
Sequence of Events
1. A train approaches a defined level crossing.
2. OBU (on train) receives GPS signals and determines that it is within time x of crossing. 3. OBU connects to RSU via frequency and ID data stored in the crossings database located on the OBU.
4. RSU acknowledges connection request.
5. OBU sends warn command to RSU with timeout long enough to allow it to cross the road at its current speed.
6. RSU begins transmitting warning audio-modulated UHF signal.
7. RSU fails to detect that it is transmitting warning signal.
8. RSU replies to OBU that it has failed to transmit the signal.
9. RSU connects to control centre via GPRS if available, and notifies control centre of RSU failure.
10. OBU disconnects from RSU.
11. OBU stores failure notification in solid state memory to pass on to control centre when within GPRS range.
12. OBU begins transmitting warning audio-modulated UHF signal.
13. OBU detects that it is transmitting warning signal OK. 14. IVU in passing road vehicle receives warning signal and relays audio warning message to speakers.
15. Driver of passing road vehicle is alerted to crossing train and stops vehicle before entering level crossing to avoid collision with train.
16. Train crosses road without colliding with road vehicle.
17. OBU receives GPS signals and determines that it has finished crossing the road.
18. OBU stops transmitting.
19. Next time in range, OBU connects to control centre via GPRS.
20. OBU notifies control centre of crossing failure.
Use case 6 - Type 1 crossing failure to transmit IVU signal
Sequence of Events
1. A train approaches a defined level crossing.
2. OBU (on train) receives GPS signals and determines that it is within time x of crossing. 3. OBU begins transmitting warning audio-modulated UHF signal.
4. OBU fails to detect that it is transmitting warning signal.
5. OBU notifies train driver with audible warning beeps and flashing red failure indicators in the OBU user interface, of the system failing and that a crossing is ahead.
6. Train driver takes extra care at crossing and manually applies warning horns, and lights, etc, at crossing.
7. Driver of passing road vehicle is alerted to crossing train through traditional audible warnings and flashing lights and stops vehicle before entering level crossing to avoid collision with train.
8. Train crosses road without colliding with road vehicle.
9. Next time the OBU is in range of GPRS it transmits a failure notification to the control centre.
10. Train driver uses backup means of notifying control centre of failure in case of GPRS out of range. /
Use case 7 - MultiTrax inside OBU failure
Sequence of Events
1. The Primary MultiTrax component inside the OBU fails to respond. 2. The redundant MultiTrax component receives no messages from the failed unit, or messages report fault of unit.
3. Redundant MultiTrax component switches control to itself for all OBU tasks.
4. Redundant MultiTrax component reports fault to locomotive operator and logs fault to solid state memory. OBU unit transmits fault via GPRS to control centre which logs the fault.
5. Redundant MultiTrax component issues a reboot command to Primary MultiTrax component to attempt revival of operation.
6. Redundant MultiTrax component continues to operate OBU.
[00212] A central component in at least some of the system units identified at paragraph 0107 is the MultiTrax component.
[00213] According to the preferred embodiment of the present invention, the MultiTrax component is essentially a multi-purpose printed circuit board assembly (PCBA) containing a highly-capable microcontroller, solid state data storage and an array of wireless and cable data and audio communications, and general purpose digital and analogue I/O interfaces.
[00214] A summary of the features of the MultiTrax component of the preferred embodiment is as follows (divided into functional groups):
Microprocessing and Data Storage:
• Atmel AT32UC3A0256 AVR32-based microcontroller with a 32-bit core, 256KB of flash, and 64KB of RAM.
• Secure-Digital (SD) card reader socket.
Radio Transceivers:
• 400-500MHz 25W (UHF) audio/data transceiver, software-configurable frequency and transmission power. Audio signal input and output break-out options. SMB antenna connector.
• GPRS transceiver based on a Telit UC864-G GPRS transceiver module. SIM card holder. SMB antenna connector.
• GPS receiver based on a Fastrax IT500 GPS receiver module. SMB antenna connector.
• Optional Iridium Module (Satellite) interface.
Cable communications interfaces:
• 10/1 OOMb/s Ethernet interface. • Full-speed (12Mb/s) USB2.0 on-the-go (OTG) port, enabling the MultiTrax component to behave as host or device.
• RS-485 port, also available as 3.3V serial interface.
• RS-232 port, also available as 3.3V serial interface.
• +3.3V SPI Master/Slave Port with 4 slave selects and an interrupt request line.
Analogue and Digital I/O:
• 8-pin Opto-isolated digital input.
• 8-pin open-drain low-side-switched digital output port.
• 2-pin analogue-to-digital voltage input port with range selection from 0-2.5V or 0- 10V.
• 2-pin digital-to-analogue current output port.
• 5-pin digital-to-analogue voltage output port.
• A total of 3 pins +3.3V general purpose digital input/output.
• An LCD module port.
Digital Audio:
• Optional mono hardware or stereo software digital audio analogue output (section 3.8) .
• Optional mono hardware or stereo software digital audio analogue input (section 3.9) .
• General purpose DIP switches
• 2-bits general-purpose switching.
Power options:
• 12-24VAC 50/60Hz Input.
• 1 1 -36VDC Input/Output.
[00215] The MultiTrax component contains a diverse range of internal components, including a high-performance microcontroller and various RF transceivers, one configuration of which is illustrated in Figure 6.
[00216] This current preferred embodiment of the MultiTrax component contains an Atmel AT32UC3 A0256- ALUT AVR32-based microcontroller. This microcontroller's capabilities include a 32-bit core, 256KB of flash, 64KB of RAM, USB, Ethernet, 7-channel 16-bit PWM, 8- channel 10-bit ADC, 3 -channel timer/counter with 6 PWM/wave outputs, 4 USARTs, 2 SPI buses, and 109 GPIOs. Future versions of the MultiTrax component may contain an ARM-based or XMEGA-based microcontroller.
[00217] Programming of the microcontroller can be done via two methods: 1. Direct programming through JTAG interface through header Jl .
2. If correct bootloader firmware already programmed into microcontroller, then via serial, USB, Ethernet, GPRS or UHF data interfaces, using the relevant commands, specified in the relevant protocol specification documents.
[00218] Direct JTAG programming is done via header J1 , for which the pin out is provided by Table 27. An AVR JTAG programming adapter and programming software is required.
[00219] The MultiTrax component will include a real-time clock (RTC) which may only keep time while the unit is externally powered. This RTC may be synchronised in software to external time sources, such as GPS, or through any one of the MultiTrax component various
communications channels.
[00220] The microcontroller uses an external 12MHz crystal, from which it generates its internal clock signals. This is required for the microcontroller's USB interface, as well as providing accurate timing for various applications.
[00221 ] Various microcontroller peripheral interfaces are provided in the the MultiTrax component of the preferred embodiment as outlined in Table 1.
Figure imgf000039_0001
Figure imgf000040_0001
Figure imgf000041_0001
Figure imgf000042_0001
Figure imgf000043_0001
Figure imgf000044_0001
[00223] The PCB is designed for two digital audio storage and playback options, which can be selected by populating the relevant components:
1. Audio stored on the SD card and played back by the microcontroller via its bitstream audio DAC and low-pass filter.
2. Audio stored-on and played-back by a dedicated digital audio device.
[00224] This digital audio option includes 2-channels of audio output from the
microcontroller's bitstream audio DAC via simple lst-order low-pass filters. One of these channels (left) is connected to the analogue input of the UHF transceiver, as well as the left channel of the external audio output connector. The other channel (right) is connected to the right channel of the external audio output connector.
[00225] A Nuvoton Chipcorder ISD 15102 digital audio recording and playback IC is connected to the microcontroller via SPI for data and control. This IC is capable of recording, storing, and playing-back up to 2 minutes of digital audio. Digital audio is readable and writable through the SPI interface using an uncompressed 16-÷bit PCM format. Its single analogue output is connected to the UHF transceiver via its analogue input pin, as well as connecting to the audio output connector left channel. There is no right-hand channel in this option. The lCs single analogue input is connected to the UHF transceiver analogue output pin, as well as connecting to the audio input connector left pin.
[00226] This IC, if installed, also provides general purpose I/O pins which are used for external LCD display interfacing and reading of 2 DIP switch states (see Table 3). 0D links are used to connect these peripherals directly to the microcontroller's GPIO pins to which this IC is normally connected, if this IC is not present.
Figure imgf000044_0002
Figure imgf000045_0001
[00227] The MultiTrax contains a UHF transceiver - for frequency shift keying (FSK) data and analogue audio communications. A preferred form is illustrated in Figure 7.
[00228] The transceiver has a carrier frequency range of 400MHz to 500MHz (currently), and contains a CML microcircuits CMX881 baseband processing IC, which is able to generate and process CTCSS and DCS squelch schemes, as well as FSK data encoding and decoding.
Transmission power is monitored and controlled using the microcontroller via ADC and PWM respectively, and is up to 5W.
[00229] The UHF transceiver has a female SMB connector for connecting an external antenna.
[00230] This transceiver has as an input the analogue output of the digital audio storage and playback solution discussed in section 2.3, mixed with an auxiliary audio input connector. The transceiver also has as output a microcontroller ADC input, and an auxiliary audio output connector.
[00231 ] This transceiver is connected directly to the microcontroller's SPI bus to input and output data.
Figure imgf000046_0001
Figure imgf000046_0002
[00232] The MultiTrax contains a Fastrax IT500 GPS receiver module (U1200). This module has an update rate of l OHz. The GPS receiver communicates with the microcontroller via the NMEA protocol using a CMOS-level serial link at 9600bps. This component is interfaced to others as in Table 6.
Figure imgf000046_0003
Figure imgf000047_0001
[00233] The MultiTrax component contains a Telit UC864-G GPRS transceiver module. This module forms a complete GPRS transceiver, able to operate on 850, 900, 1800 and 1900MHz bands. This module connects to a SIM card holder in which the network's required SIM card will be installed. This component is interfaced to others as in Table 7. This module includes a 50□ Murata GSC antenna connector. This is linked via a GSC cable to a UFL connector mounted on the MultiTrax PCB.
Figure imgf000047_0002
Figure imgf000048_0001
[00234] The MultiTrax component contains a DP83848I physical layer Ethernet transceiver, which is connected directly to the microcontroller via Media-independent interface (Mil).
[00235] A Maxim MAX-3241 device is used to convert voltage levels from the RS-232 standard to the microcontroller USART0 interface level (3.3V).
Figure imgf000048_0002
Figure imgf000049_0002
[00236] A RS-485 physical-layer Intersil ISL83086 IC is used to interface the external RS- 485 connector to the microcontroller.
Figure imgf000049_0001
[00237] Several internal components communicate to the microcontroller through a internal SPI bus (microcontroller SPIO). These components are:
1. UHF CMX881 baseband processing IC (SPIO hardware slave select 0).
2. UHF PLL synthesiser (SPIO hardware slave select 1 ). 3. SD card (SPIO hardware slave select 2).
4. Digital audio recorder IC (SPIO hardware slave select 3).
5. LCD (software slave select - GPIO 19).
[00238] The MultiTrax component contains an LED which may be switched on/off via microcontroller GPIO 109 pin.
[00239] The MultiTrax component is a general purpose radio communications and I/O module. The PCB is designed to act either as a main board or a plug-in module, depending on the type of connectors for which it is populated. Each connector has allowances to act as either a top-facing stand-alone connector, or a downward-facing set of pins if the board is to act as a plug-in module.
[00240] The Multitrack component has two power supply ports - one for 12-24V AC, and the other for 11-36V DC power. Only one of these inputs is required to be powered at any one time.
[00241 ] This is provided through connector Jl , and is required to be externally isolated with respect to board GND, which is used for much of the board's I/O. The connector type is a Weidmuller LM2NZF 5.08/04/135 3.5SN OR BX. The pin assignment for this connector is given in Table 10.
Figure imgf000050_0001
[00242] This is provided through connector J2, and is required to either be externally isolated with respect to board GND, or its negative wire must be at the board's GND potential, as the negative terminal is internally connected to the board's power GND. The connector type is a Weidmuller LM2NZF 5.08/06/135 3.5SN OR BX. The pin assignment for this connector is given in Table 1 1.
Figure imgf000050_0002
[00243] General Purpose Analogue and Digital Input/Output Port A (GPADIO-A) J3 (see Table 12 for pin assignment) is a general -purpose analogue and digital input/output port, consisting of:
1. 8 Opto-isolated digital input pins.
2. 2 Analogue Input Pins.
3. 2 Analogue Current Output Ports (2 pins each).
4. 1 +3.3 V Digital Input/Output Pin.
[00244] J3 is a 34-way right-angle IDC locking header, similar to that shown in Figure 3. The pins of J3 are also repeated in the phoenix connectors J3A to J3E (see Table 14 to Table 20 for pin assignments).
Figure imgf000051_0001
Figure imgf000052_0001
Figure imgf000053_0001
Figure imgf000053_0002
[00245] GPADIO Port A contains 8 general purpose digital input pins, provided through connector J3.
[00246] The MultiTrax component contains two analogue input pins, for analogue-to-digital conversion, provided through connector J3. Each pin has a resolution of 10 bits, and its range can be selected using DIP switches between 0-2.5V or 0-1 OV. Each pin is also over-voltage protected to 100V continuous, and low-pass filtered to 100kHz, for EMC (and anti-aliasing).
[00247] The MultiTrax component contains two analogue output ports, for digital-to- analogue conversion to currents, provided through connector J3. Each port has a resolution of 16 bits, and can output between 0-20mA. Each output (high-side and low-side) has a voltage range of 0-10V. The interface has a maximum bandwidth of 1kHz. To convert the output to a voltage a user may connect the low side to GND via a 470□ resistor, and connect the high side directly to the 12V rail.
[00248] J3 and J3E contains a +3.3V general-purpose digital I/O pin.
[00249] The GPADIO-B port (J5) contains 5 analogue voltage output pins with a range of 0- 3.3V, and two general-purpose +3.3V digital voltage input/output pins (see Table 19 for pin assignment). The connector for this port is a 10-way 0. l"-pitch IDC locking header.
Figure imgf000053_0003
Figure imgf000054_0002
[00250] The MultiTrax component contains 8 general purpose digital output pins, provided through connector J4. Each pin is a low-side switching open-drain MOSFET output.
[00251 ] The pin assignment for J4 is identical to that of the Weidmuller RSM 8-channel relay adapter board (Weidmuller part no. 0122800000 / 03834000000 / 02364000000). J4 is a 10-way IDC locking header.
Figure imgf000054_0001
[00252] J8 is a 2-bit +3.3 V general-purpose digital I/O port (GPDIO) with pin assignment shown in Table 20.
Figure imgf000054_0003
[00253] The LCD module port, Jl 2, is for connection of an SPI-compatible LCD via a custom adapter board. The connector is a 10-way IDC locking header with pin assignment shown in Table 21.
Figure imgf000055_0001
[00254] J6 is a dual +3.3V serial / general purpose digital I/O port, with pin assignment given in Table 18. The connector is a 10-way IDC locking header. Port 0 may not be in use simultaneously with RS-232, and port 1 may not be in use simultaneously with RS-485, as these share microcontroller internal USART modules respectively.
Figure imgf000055_0002
[00255] The MultiTrax component contains a high-impedance digital audio analogue output port interface, J7 (3.5mm stereo socket), for connecting external analogue audio equipment. This port also forms the UHF transmitter auxiliary input and is effective when overridden by a low- impedance signal on this port. The audio inputs and outputs are also included in a 5-way SIL header, J 19.
[00256] The MultiTrax component contains a high-impedance digital audio analogue input port interface, J18 (3.5mm stereo socket), for connecting external analogue audio equipment. This port also forms the UHF transmitter auxiliary output but is effective as an input when overridden by a low-impedance signal source. The audio inputs and outputs are also included in a 5-way SIL header, Jl 9.
[00257] J19 is a SIL 5-way header which includes the audio inputs and outputs of J7 and Jl 8. Jl 9 has pin assignment given in Table 23.
Figure imgf000056_0001
[00258] A software-configurable RS-232 interface is provided through J9, a (male shell, female pin) DB9 connector which complies with the DB9 RS-232 standard pinout. The MultiTrax component operates as a Data Circuit-Terminating Equipment (DCE, peripheral) via this port, and is therefore able to take on the functionality of a traditional serial port modem, if running appropriate software. A footprint for a 10-way IDC locking header, J9H, with identical pin assignment, also provides this interface.
[00259] The MultiTrax component contains an RS-485 connector, J10, which is an RJ-45 connector for easy connection of commodity unshielded twisted-pair (cat-5 UTP) cables. A footprint for a 10-way IDC locking header, J10H, also provides this interface.
[00260] The board-to-board connector, J1 1 (pin assignment given in Table 24), contains signals for enabling two adjacent MultiTrax component boards to conveniently communicate. The port consists of a software-configurable master/slave SPI port with IRQ line, enabling the slave to initiate transactions and removing the requirement for the master to poll the slaves.
Figure imgf000056_0002
Figure imgf000057_0002
[00261 ] The MultiTrax component contains 3, 50□ SMB connectors for connecting antennas to each of its 3 radio communications transceivers/receivers:
1. J13 - UHF Transceiver
2. J14 - GPS Receiver
3. J15- GPRS Transceiver
[00262] The MultiTrax component contains an On-The-Go (OTG) USB interface (J16, micro-AB connector). The unit may take on the role of a USB host or self-powered device via this interface. The USB interface will automatically detect which mode to operate in, depending upon the type of USB micro plug (A or B) connected. The interface may operate in full-speed (12Mbit/s) and low-speed (1.5Mbit/s), and is of course backwards compatible with external USB 1.1 hosts and devices.
[00263] A footprint for a 5-pin header, J16H, with pin assignment given in Table 25 also provides this interface. A DIP switch provides an override of the USB-ID pin of the microcontroller to short it to GND, in the case that the MultiTrax component is to behave as a USB host when using the header.
Figure imgf000057_0001
[00264] The MultiTrax component contains a wired Ethernet interface connected via its RJ- 45 connector, J 17. [00265] The JTAG connector (J20) uses the AVR JTAG de-facto standard pin assignment (see Table 26) and 10-pin box header format.
Figure imgf000058_0001
[00266] J21 is an optional +3.3V serial port for debugging purpose for the GPRS transceiver. It is connected internally to the GPRS module's secondary serial interface intended for debugging, and has pin assignment as given in Table 27. J21 is a 5-pin SIL header.
Figure imgf000058_0002
[00267] J22 is an optional +3.3V serial port for debugging purpose for the GPS transceiver. It is connected internally to the GPS module's second serial interface, and has pin assignment as giVen in Table 28. J22 is a 5-pin SIL header.
Figure imgf000058_0003
[00268] J23 is an optional port for debugging baseband signals for the UHF transceiver. J23 has pin assignment as in Table 29 and is a 5-pin SIL header.
Figure imgf000059_0001
Figure imgf000059_0002
Figure imgf000060_0001
[00269] The preferred embodiment of the MultiTrax component has the following radio interfaces:
1. Radio Audio and Data Communications (UHF) Transceiver.
2. Global Positioning System (GPS) Receiver.
3. General Packet Radio Service (GPRS) Transceiver.
4. (Optional) Iridium Transceiver Voice and Data or SBD Transceiver.
[00270] The PCB is to be no more 200mm x 120mm x 50mm in size. The board has 6 M3 mounting holes - 4 in each corner, and 2 at the middle point of the longer sides. Along the bottom edge of the board, locking IDC headers are available for connecting the board to application-specific boards. The board should weigh no more than 200g.
[00271 ] The MultiTrax component's main microcontroller runs the free real-time operating system (RTOS) FreeRTOS, however in future versions the IEC61508 SIL-3 certified SafeRTOS may be used.
[00272] SafeRTOS is based on FreeRTOS, and porting code from FreeRTOS to SafeRTOS is straight-forward, so it is envisaged that this RTOS upgrade in future will be trivial.
[00273] The software includes a FAT-16 file system library to aid reading and writing of data to/from the SD card.
[00274] The software structure is based on a standard API interface to upper level applications. The API interfaces with lower level hardware providing a standard interface easier upper level coding.
Figure imgf000061_0001
Figure imgf000062_0001
[00275] Apart from the MutiTrax component, the most important component in the apparatus of the present invention is the in vehicle unit (IVU) described briefly above.
[00276] The IVU of the preferred embodiment is a UHF radio receiver which is plugged in between a vehicle stereo unit and the power/speaker cabling. When the IVU receives a warning message it directs the incoming message to the vehicle speakers. It also controls the power to the speakers such that it can disconnect or override the signal from the stereo to the speakers, and/or power the speakers if the stereo is off. The schematic location according to the preferred embodiment of the IVU in relation to the vehicle stereo, speakers and power supply is shown in Figure 8.
[00277] The IVU also has the ability to receive data messages via UHF, which it passes on to an external in- vehicle computer via a serial cable connection, or via and optional Bluetooth transceiver.
[00278] The IVU also has the optional ability to function as a Bluetooth mobile phone hands free kit. This uses the vehicle's speaker system and a microphone which is installed in the vehicle and plugs into the IVU.
[00279] If the power supply to the IVU is interrupted/fails the power supply to the car stereo is also cut, thus notifying the vehicle operator of a problem.
[00280] During start up the IVU carries out a self-test by transmitting a small test signal to itself. If it does not confirm it is operating correctly the speakers will remain muted; thus notifying the vehicle's operator of the IVU' s failure.
[00281 ] Situations may arise where multiple messages are being broadcast simultaneously. In this situation it would be necessary to determine the most important messages and ensure that the message with the highest priority is received. An example of this would be a motorist approaching a rail level crossing and receiving a message that an ambulance was approaching. Although it is appropriate that the ambulance transmits this warning, it may temporarily distract the driver and result in minimised attention to the level crossing. Should a train be approaching this level crossing, the warning of the highest priority would be determined that a potential for a collision with the train would take precedence. In this instance, the IVU would be able to make this determination and switch to the higher priority warning. The ambulance would also be notified of the train's presence.
[00282] Figure 9 provides a functional overview of the IVU and its major internal components.
[00283] The IVU contains a Texas Instruments MSP430F2132 as its principal
microcontroller. This IC has 512 bytes of SRAM, eight 10-bit ADC channels, 24 GPIO pins, two 16-bit timers, 8KB of flash program memory, 256 bytes of flash data memory, 3 capture/compare registers, a serial communications interface and an SPI interface. A 16MHz crystal oscillator is used as the clock for this microcontroller as it requires maximum performance and accurate timing to measure CTCSS tones.IVUs may only be programmed via the JTAG interface connector P900. A suitable Spy-bi-wire MSP430 JTAG programming adapter and programming software can be used for programming.
[00284] The receiver is a dual conversion superheterodyne with a front-side low-noise amplifier (LNA). The UHF receiver contains a TB31202 PLL whose frequency is adjustable by the microcontroller via SPI. An MC3372 FM IF demodulator IC is used, which provides an RSSI input to microcontroller ADC channel 2. The first mixer is based around the BF998 dual-gate MOSFET. Refer to section 4 for detailed radio specifications. The PLL is to be capable of locking to a frequency outside of the front-side RF band-pass filters as a "quiet" frequency for the POST (see section 6.1).
[00285] The IVU RF communications employ a continuous tone-coded squelch system (CTCSS). The baseband signal is directed through a 60Hz-260Hz band-pass filter, which is then connected to an interrupt input pin of the microcontroller, allowing CTCSS tone frequencies to be measured in firmware, and therefore firmware-configurable.
[00286] The IVU will optionally contain an internal Bluetooth chipset and on-board
Bluetooth antenna. This allows the IVU to act as a mobile phone hands-free system, as well as allowing the IVU to communicate with nearby computing devices. Such computing devices may then be used to configure the IVU during installation or maintenance, as well as receive UHF- transmitted data.
[00287] The internal UHF transmitter uses a clock output from the microcontroller which is band-pass filtered to yield the 432MHz harmonic of the 16MHz clock signal. This is activated only for the first 5s after power-up.
[00288] The board contains 4 DPDT relays, 2 of which are for switching the front speakers between stereo and IVU audio outputs, and 2 of which are for opening the 4 rear/other speaker circuits (muting). The front speaker relays switch both positive and negative speaker outputs between head unit and IVU audio amplifier, but only the positive outputs are switched between closed and open circuit for the rear/other speaker channels. These relays, along with the telephone mute function of the stereo, are individually interfaced to the microcontroller, allowing software to delay to ensure a 100ms time lag between mute line activation and relay switching, as well as the reverse.
[00289] The audio amplifier is an MP7720-based class-D amplifier to reduce heat dissipation. This single ended amplifier is connected to both front speaker outputs. Audio gain is controlled via the digital potentiometer (section 2.9). The amplifier is designed not to sustain damage in the case of shortcircuited speaker outputs. This amplifier is capable of outputting 20W RMS continuous at 90% efficiency.
[00290] A differential amplifier is used to convert the head unit's front left speaker output to a ground-referenced signal for input to the microcontroller, so it can count the audio signal frequency, in the case that the unit receives a portable calibration unit (PCU) radio signal. This is to confirm that the IVU is being calibrated, and that the PCU radio signal is not a stray signal from another IVU being calibrated. A service person simply plays an audio CD or cassette containing the correct tone on the head unit when the IVU is being calibrated.
[00291 ] The IVU board contains an AD5165 digital potentiometer which the microcontroller accesses via the SPI bus to control the audio amplifier gain.
[00292] The IVU contains an internal linearly-polarised UHF helical antenna, which is oriented lengthways within the enclosure. Alternatively an SMB connector is mounted on the same PCB footprint, allowing external antennas to be connected.
[00293 ] The unit contains 5 linear voltage regulators: 1. 5 V for RF and analogue circuits.
2. 2.8V for microcontroller
3. 2.8V for PLL and reference oscillator VCTCXO
4. 2.8V for VCO
5. 10V for mixer
6. Relays are supplied directly from the vehicle power input.
7. Class-D audio amplifier supplied directly from power input.
[00294] A 3A fuse is contained in the unit to prevent overheating and over-current in case of malfunction.
Figure imgf000065_0001
Figure imgf000066_0001
[00296] The IVU of the preferred embodiment has a number of external interfaces.
[00297] The IVU of the preferred embodiment has the following communications interfaces: 1. The IVU acts as a receiver, receiving signals from OBUs (Crossing type 1 case and failure of RSU in crossing types 2 and 3 case) or RSUs.
2. Audio signal output directly driving vehicle audio system speakers.
3. Audio signal input from vehicle head unit.
4. Wired serial communications interface to in- vehicle computer.
5. Bluetooth interface.
[00298] The IVU of the preferred embodiment has the following External Electrical Interfaces: 1. Vehicle Power input.
2. Vehicle Power output to head unit.
3. Head unit telephone mute signal. 4. Speaker inputs (from vehicle's head unit)
5. Speaker outputs (to vehicle's speakers)
6. Optional external Antenna
7. Optional microphone input
[00299] The IVU is able to operate from a 12-24VDC supply with a negative chassis only. The IVU connects to power using an ISO 10487 standard power (type A socket) connector, P2, and passes on power to the audio system using P3, a type A plug of the same standard. Between power connectors, the IVU can pass up to 10A of current through the Earth (0V) and switched +12-24V rails, and up to 1 A on all other rails.
[00300] The IVU only draws current from the switched DC supply (pin 7 of the ISO 10487 connector).
[00301 ] Typically the IVU draws ~500mA of quiescent current, and ~1A when receiving and playing a warning message over the front speakers. As the IVU draws non-negligible current, it is advised that it is wired correctly as in Figure 3, to only be supplied with power when the vehicle is in use (e.g. when ignition key in "accessories" or "on" position), to prevent draining of batteries. During operation, the IVU may draw a maximum of 3A of current.
[00302] The mute function of the stereo is used via pin 1 of the type A connector, if available, as an extra precaution to prevent damage to the stereo's speaker outputs when disconnecting the speakers.
[00303] The IVU of the preferred embodiment is connected to the head unit' s speaker outputs. The IVU can switch off up to 6 speaker channels, 2 of which (front speakers) it can relay warning audio signals. Switches are able to pass up to 30V RMS (with respect to chassis) and 2A of current when not interrupting the normal speaker circuits. The regular 4 speaker inputs are connected through P4, an ISO 10487 plug type B. An additional 2 speaker inputs may be connected through PI . The PCB also includes holed pads for each connector pin to solder wires directly in future if required.
[00304] Inside the IVU, 32V transient voltage suppressing diodes are placed across the speaker outputs to prevent transient voltages from damaging the head unit. This could otherwise occur in the case of the speakers becoming disconnected from the head unit during high speaker currents, due to the inductive properties of the speakers and speaker wiring, and possible inductance within the head unit itself. [00305] The front left head unit speaker output is used within the IVU to confirm that it is being calibrated, in the case of the unit receiving a PCU radio signal . When being calibrated, the service person is to ensure the head unit is outputting the correct tone, either using a prepared audio CD or tuning the head unit's radio receiver to a small FM transmitter which outputs the correct tone.
[00306] The IVU of the preferred embodiment has audio signal outputs. The IVU is able to tolerate minimum speaker impedances of 3.5 Ohms. As is usually the case, front speakers must be wired to be electrically floating with respect to chassis potential. Front speakers must be rated to handle 10W RMS continuous audio power at any audio frequency. Up to 6 speakers may be connected to the audio signal output connector, but only 2 of these - the front speakers - will have audio signals from the IVU - the other 4 will only have their circuits opened and closed by ■the IVU.
[00307] The regular 4 speakers are connected through P6, to which an ISO 10487 socket type B adapter may be connected. An additional 2 speakers may be connected through P5.
[00308] A set of holed pads are also to be placed on the PCB to allow future direct soldering of adapter wires to the board.
[00309] The IVU's audio amplifier is short-circuit protected to prevent damage to the unit in the case of accidental shorts of speaker wiring.
[00310] The design of the IVU of the preferred embodiment allows for an optional external 50Ω SMB antenna edge connector to connect an external antenna. The PCB design allows for easy selection between this connector and the default internal helical antenna (see section 2.10), both using the same PCB footprint.
[00311 ] The unit is to be placed close behind the vehicle's audio head unit, or other location behind the dashboard, hidden from the road vehicle driver. The unit is housed in a flanged ABS (plastic) rectangular-prism-shaped enclosure with holed flanges at either end for secure mounting.
[00312] The IVU should be securely mechanically mounted within the vehicle to reduce fatigue on connectors and wiring, and prevent the unit from causing nuisance vibrations and knocking sounds. The unit may be mounted in any orientation, as the radio frequencies received are circularly polarised. [00313] The IVU should weigh no more than 200g excluding external electrical adaptors. The dimensions of the enclosure are 1 14mm x 63mm x 28mm, (138mm long including flanges), and mounting holes sized 5mm separated by 42mm. The enclosure may be any colour.
[00314] The significant power dissipating components are: 1. The audio power amplifier - 2W maximum (90% efficiency at 20 W) - only dissipating when receiving radio signal.
2. The speaker switching relay coils - 600mW (4 relays at 12V across 960Ω) - only
dissipating when not receiving radio signal.
[00315] Therefore the maximum power dissipated within the IVU is ~2W.
[00316] The IVU design allows it to be installed in a vehicle using the following procedure: 1. Remove vehicle audio system head unit or use some other means to gain access to audio system wiring.
2. Designate a location to mount the IVU, considering its size, mounting flanges and wiring connections.
3. Mount the IVU mechanically.
4. Connect the IVU wiring.
5. Determine the optimal location within the vehicle for the antenna for maximum received radio signal power.
6. Re-install vehicle audio system and dash.
7. From outside the vehicle, use the portable calibration unit to calibrate the IVU's squelch sensitivity and audio levels (microphone in vehicle connected via cable), or use the configuration terminal interface to manually calibrate.
[00317] As the unit is self-testing, once installed it is never required to be manually tested. Drivers should however regularly use their vehicle's audio system to ensure that the unit is not continuously blocking audio, which occurs when the self-test fails.
[00318] The unit is not designed to be repaired - in the case of malfunction the unit must be replaced. The unit may be recalibrated at any time using a portable calibration unit. The firmware is not field upgradeable, it may only be programmed in the factory or by an authorised service person.
[00319] The behaviour of the IVU is characterised by the flow charts of Figure 10 though Figure 13. On power-up the behaviour is described by the power-on self-test (POST) flow chart of Figure 10. If the POST is successful, the IVU behaves as per the idle/scanning flow-chart of Figure 1 1. When an IVU transmission is received, the IVU behaves as per the receiving signal flow-chart of Figure 12, unless the transmission is from a portable calibration unit, in which case it behaves as per the calibrating flow chart of Figure 13 (as indicated in the idle/scanning flowchart).
[00320] The software is designed to exhibit the following behaviours in order to reduce message repetition and reduce occurrences of missing higher-priority messages: 1. Scans radio channels from highest to lowest priority, so highest-priority messages are most likely to be received, and received before lower-priority messages.
2. When it recognises a valid CTCSS tone on a channel, it plays the audio message on the vehicle's speakers.
3. After playing the message on the vehicle's speakers, it remembers that it has done so for that channel. This memory times-out ("fades") after a configurable number of seconds (e.g. 15s) of radio silence on that channel, so any more transmissions on that channel are considered to be new messages, not repeats of the same message.
4. When finished playing an audio message, the IVU restarts scanning from the highest- priority channel again, not continuing to lower-priority channels than the one played. 5. The unit times the length of an audio message. If it is longer than a maximum period of 5s, it temporarily abandons playing the message to scan higher-priority channels. If the other channels are silent, it continues playing the message for another 5 s, and so on. 6. The unit only plays audio messages when receiving radio signals above a certain signal strength threshold.
7. The unit recognises audio messages from some radio signals below the signal strength threshold, but doesn't play them. It uses this knowledge to ensure it correctly plays a full message, and does not miss the start of a message, in the case the transmitter comes into range mid-message.
8. When scanning, if the unit recognises FS data, mid-packet, it waits up to 1 s for a full packet to be re-transmitted.
9. When detecting an FSK data signal, the unit stays locked to the channel for up to Is, before moving on to the next channel.
[00321 ] The software will not be required to be remotely updatable and will therefore require no bootloader. As it is a simple single-tasking system, it will not require a real-time operating system (RTOS). To maximise portability, re-use and future maintainability the software will be written in C.
[00322] The software will not use any external libraries except those specific to the microcontroller.
[00323] To make the software as reliable, predictable, maintainable and simple as practical, the software is to have a well-organised hierarchical structure of modules. Dependencies and function calls are to be one-way only - from higher-level modules to lower-level modules, the lowest level being the microcontroller-hardware interfaces and the highest being the controller module. To keep the software reliable and maintainable in future, all changes should also make use of this design principle.
[00324] The MSP430F2132 microcontroller has only 8KB of program memory, 256 Bytes of non- volatile data memory, and 512 bytes of RAM. Larger amounts of data (e.g. radio frequency tables), are to be hard-coded as constants to prevent them being placed into RAM. Groups of radio frequencies which exist as a linear series of channel frequencies of equal spacing may be suitably put into a compact data type which specifies base frequency, spacing and quantity of frequencies.
[0032S] Function-calling levels are to be no more than 10 layers deep, to reduce the required stack size.
[00326] The structure is to be modular and hierarchical to prevent two-way calling problems and to maximise code re-use.
[00327] The software essentially consists of the following modules and sub-modules
(illustrated in Figure 14 with each module detailed below): 1) Controller/main loop module (CM).
This is the central point from which the rest of the software is controlled. This calls the Initialisation Sub-Module (ISM) and then POST sub-module (POSTSM) on power-up, and then calls on Calibration Sub-Module (CSM) and Receiving Message Sub-Modules (RSM) as required, during normal operation. The CM makes calls to . the lower-level modules of the software:
■ Audio Control Module (ACM)
■ Radio Communications Module (RCM)
" Settings Module (SM) ■ Timer Module (TM)
■ Hardware Module (HW)
a) Initialisation sub-module (ISM)
This sub-module calls the required initialisation routines of all other modules on power-up to ensure they can begin to function correctly and serve the CM as required.
External function call interfaces:
ISM_Init() - This, along with POSTSM_POST, is to complete in less than 3s b) Power-on self-test sub-module (POSTSM)
This sub-module is called immediately after initialisation and performs the POST. External function call interfaces:
POSTSM_POST() - This, along with ISM_Init, is to complete in less than 3s. c) Calibration sub-module (CSM)
This sub-module performs auto-calibration of the receiver when radio messages from a PCU are received.
External function call interfaces:
CSM_Calibrate()
d) Receiving sub-module (RSM)
This sub-module is for receiving a IVU warning message during normal operation of the IVU.
External function call interfaces:
RSM_Receive()
) Audio Control Module (ACM).
a) Audio amplifier gain and speaker switching/muting control sub-module (AGSM). b) Audio measurement sub-module (AMSM).
The audio control module controls the audio amplifier gain, reads amplifier output levels, and switches speakers and the telephone mute line of the head unit. Additionally, it determines the tone of the audio being output by the head unit, to determine whether it is signalling a calibration of the IVU.
External function call interfaces
1. ACM InitO - Initialises module.
2. ACM_IVU() - Mutes head unit, switches speakers to IVU and sets audio amplifier gain to stored setting.
3. ACM_HeadUnit() - Sets audio amplifier gain to zero, switches speakers to head unit and unmutes head unit. 4. ACM_Testing() - Switches speakers to head unit, unmutes head unit and sets audio amplifier gain to stored setting.
5. ACM_Fault() - Mutes head unit, mutes audio amplifier, and switches speakers to IVU.
6. TAudioLevel ACM_GetAudioLevel() - Measures audio level from audio amplifier output, for POST.
7. Boolean ACM CalibrationToneMatchO - Returns whether the frequency of the audio input from the head unit matches the calibration tone. This is used to confirm that the unit is being calibrated.
Interrupt service routines:
ACM_HeadUnitPulse() - Called once every head unit audio signal cycle, and used to determine head unit audio output frequency.
Data Types
TAudioLevel - 16-bit unsigned integer representing ADC reading. ) Radio Communications Receiver module (RCM)
The radio communications receiver module provides all functionality for receiving radio messages, including CTCSS signalling.
a) CTCSS tone sub-module (CTSM).
b) FSK demodulation sub-module (FSKM)
c) UHF receiver controller sub-module (URCSM).
External function call interfaces
1. Boolean RCM_Init() - Initialises the radio communications module, returns true if successful, false if failure.
2. TChanID RCM_GetChan() - Gets the channel which the receiver is currently locked to.
3. Boolean RCM SetChan(TChanlD) - Sets radio channel, returns true if successful, false if error.
4. TRSSIStatus RCM CheckRSSIO - Indicates whether received signal is within range, out of range or non-existent.
5. TRxCTCSSStatus RCM_CheckCTCSS() -Returns whether the CTCSS tone is valid for the current channel.
6. RCM_CalibrateRSSI() - Saves the current RSSI as the squelch threshold.
7. Boolean RCM_QuietChan() - Locks tuner to the designated quiet channel, in which there is no RF signal. Returns true if successful, false if failure. 8. Boolean RCM_POSTTxChan() - Locks tuner to the designated internal test transmitter frequency. Returns true if successful, false if failure.
9. RCM_SetRxDataCallback(function pointer) - Sets the data callback function for receiving bytes over UHF. This allows the radio communications module to pass received bytes back to higher level functions.
Other modules Called
) Settings module (SM)
The settings module provides a central repository of settings which other modules may call upon. Some settings are hard-coded as C code, while others may be stored in nonvolatile memory. The settings stored consist of:
1. UHF channels in order of priority (Hard-coded):
a. Carrier frequency
b. CTCSS tone frequency
2. Audio gain setting (Non- volatile memory)
3. Squelch threshold and hysteresis RSSI setting (Non-volatile memory)
4. PLL Reference oscillator tuning P WM setting.
5. 2nd local oscillator tuning PWM setting.
External function call interfaces
1. TChanData SM_GetUHFChannelData(TChanID)
2. TChanID SM_GetQTYChannels() - Gets the quantity of channels listed in the settings table.
3. TAudioGain SM_GetAudioGainSetting()
4. SM_SetAudioGainSetting(TAudioGain)
5. TRSSI SM_GetSquelchRSSISetting()
. 6. SM_SetSquelchRSSISetting(TRSSI)
7. TRSSI SM_GetSquelchRSSIHysteresisSetting()
8. SM_SaveSettingsToFlash()
9. SM_GetRefTuneSetting()
10. SM_Get2ndLOSetting()
1 1. SM_Update()
12. TCTCSSPeriod SM_GetCTCSSPeriod()
External function calls
SM_Ext_AudioGainChanged()
Data Types 1. TChanID - 8-bit unsigned integer representing a unique UHF channel. Does not necessarily
2. correspond to any external set of channel numbers. Channels in settings are
numbered
3. consecutively from 0 to the quantity of channels minus 1.
2. TRSSI - 16-bit unsigned integer representing RSSI ADC reading.
3. TCTCSSPeriod - 8-bit unsigned integer representing period of CTCSS tone in ' lOOus.
4. TRadioFreq - 16-bit unsigned integer representing radio frequency, such that x = (f- 400MHz) /2kHz.
5. TChanData - Structure contains:
a. TRadioFreq
b. TCTCSSPeriod
6. TAudioGain - 8-bit unsigned integer representing digital pot setting.
5) Timer module (TM).
a) Tone measurement sub-module (TSM).
The timer module provides a mechanism for other modules to accurately measure or wait for a period of time. This can be used for tasks such as CTCSS tone measurement, or waiting for a period of time before scanning frequencies or completing a power-on self- test, etc.
External function call interfaces:
1. TM_Init()
2. TusCount TM_GetMicroSeconds() - Gets a rolling microsecond count.
3. TM Wait(TusCount) - Waits for the given period of time before returning. 4. TM_StartTimer(TTimer, TusCount) - Starts a timer
5. Boolean TM TimerFinished(TTimer) - Returns whether a timer has finished. 6. TusCount TM_TimerElapsed(TTimer) - Returns the amount of time which has elapsed since the given timer was started.
Interrupt service routines:
TM_Overflow() - Called when the 16-bit hardware timer register overflows.
Data Types
TusCount - 32-bit unsigned integer representing a microsecond count.
6) Hardware abstraction layer module (HW).
External function call interfaces HW_Init() - Initialises module.
HW_PLLSetDivider(unsigned int) - Sets PLL VCO divider.
HW_PLLSetReference(unsigned int) - Sets reference oscillator divider.
HW_DigiPotTx(char) - Transmit a byte to the audio gain digital potentiometer. Unsigned short HW_ADCReadRSSI() - Reads the RSSI from the ADC.
Unsigned short HW_ADCReadAudioLevel() - Reads the audio power amplifier signal level from the ADC.
Unsigned short HW ADCReadMicLevelO - Reads the microphone sound level from the ADC.
Unsigned short HW_ADCReadTemperature() - Reads the temperature from the microcontroller's internal temperature sensor.
HW_SetCTCSS_ISR() - Sets the CTCSS interrupt service routine callback function.
HW EnableFSK(boolean) - Enables or disables FSK demodulation interrupt service routine.
HW_Set_HUAudioTone_ISR(function pointer) - Sets the head unit audio tone interrupt service routine callback function.
HW_FlashWrite(Data, Size) - Writes the given data to the non-volatile flash data storage area of the microcontroller.
HW_SetNotchTunePWMValue(unsigned short) - Sets the notch filter tuning PWM value.
HW_SetRefTunePWMValue(unsigned short) - Sets the PLL reference oscillator tuning PWM value.
HW_Set2ndLOTunePWMValue(unsigned short) - Sets the 2nd local oscillator tuning PWM value.
HW_SerialTxByte(char) - Transmits a byte out of the wired serial
communications port.
HW_SetRxByteISR(function pointer) - Sets the callback function for receiving byte from the wired serial communications port.
HW_SerialTxString(string) - Transmits a string out of the wired serial communications port.
HW_ServicePendingTimerInterrupt() - Services any pending timer overflow interrupts, and is required to be called during service of any other interrupt when attempting to read the timer. [00328] The IVU software has a hierarchical modular structure to maximise software reliability, maintainability and code re-use for other projects. The arrows in Figure 14 are in direction of control (i.e. function-calling).
[00329] The wired serial port includes a configuration and status interface, which enables external computers/terminals to configure IVU settings and receive updates about IVU status. The interface reports RSSI once per second.
[00330] Data received over UHF is passed on through the serial port, as an ascii hexadecimal representation. Each byte is enclosed by '<' and '≥', e.g. "<D4≥." The start of each packet is represented by a "#" and the end of the packet is represented by a "$". An example of a packet of multiple bytes:
#<12≥<FD≥<F3≥<14≥<12≥<34≥<45≥$
[00331 ] The IVU does not output the bit sync and frame sync bytes, only the content of each packet. The IVU also does not perform checksums on the data packets, it simply relays the raw data it receives. It is up to the higher-level software to perform checksums, etc, to determine packet validity. The IVU only relays data When it receives a full 9 bytes after the frame sync.
[00332] In order to further illustrate the system of the present invention, a number of software use cases and testing protocols for the IVU are provided as examples of operation as follows:
Use Case 1 - Power On
1. Power is switched on.
2. Speakers are immediately switched to head unit (no muting).
3. Radio receiver tunes to quiet channel and confirms white noise level on amplifier output. 4. Radio receiver tunes to internal transmitter and confirms silence on amplifier output. 5. Less than 3 s since power-on.
Use Case 2 - No Signal Received (Idle)
1. Speakers remain switched to head unit (no muting)
Use Case 3 - Normal Valid Audio Signal Beginning to be Received
Pre-conditions:
1. No signal being received (Idle).
Sequence of events:
1. Valid radio signal is received by IVU.
2. IVU enters receiving message state. 3. Speakers switch to IVU and head unit muted.
4. Received audio audible on speakers, with volume high enough to compensate for ambient noise detected on microphone.
e Case 4 - Normal Valid Audio Signal with First CTCSS tone marker
Pre-conditions:
1. Normal valid signal beginning to be received.
Sequence of events:
1. Valid radio signal continues to be received by IVU, and continues to be relayed to audio speakers.
2. A small break of tone, or other pre-defined CTCSS tone marker occurs.
3. IVU recognises that it has now heard the start of the message.
5. Valid radio signal continues to be received by IVU, and continues to be relayed to audio speakers, with volume high enough to compensate for ambient noise detected on microphone.
e Case 5 - Normal Valid Signal with Second CTCSS tone marker
Pre-conditions:
1. Normal valid signal with first CTCSS tone marker.
Sequence of events:
1. Valid radio signal continues to be received by IVU, and continues to be relayed to audio speakers.
2. A small break of tone, or other pre-defined CTCSS tone marker occurs.
3. IVU recognises that it has now heard the full message, but maintains message count for this channel:
4. Speakers switch back to head unit without mute.
e Case 6 - Valid Signal Terminates
Pre-conditions:
1. Normal Valid Signal Beginning to be Received, or
2. Normal valid signal with first CTCSS tone marker, or
3. Normal valid signal with second CTCSS tone marker.
Sequence of events:
1. Valid radio signal reception ceases.
2. IVU resets message count to zero for channel.
3. Speakers switch back to head unit without mute.
se Case 7 - Valid Signal Terminates with Lower-Priority Signal Continuing
Pre-conditions: 1. Normal Valid Signal Beginning to be Received, or
2. Normal valid signal with first CTCSS tone marker, or
3. Normal valid signal with second CTCSS tone marker.
Sequence of events:
1. Valid radio signal reception ceases.
2. IVU scans for lower-priority signals.
3. IVU recognises lower-priority signal being received, and begins relaying to speakers.e Case 8 - Calibration
1. Valid tone playing on head unit using given audio CD or other mechanism.
2. Valid calibration radio signal is received by IVU.
3. Speakers switch to IVU, initially with no audio output, and head unit muted.
4. After 1 second, audio gain begins to increase.
5. When audio level at specification, radio signal is switched off.
6. IVU retains squelch RSSI and audio gain settings now calibrated.
e Case 9 - Power On with Audio Amplifier Fault
1. Power is switched on.
2. Speakers are immediately switched to head unit.
3. Radio receiver tunes to quiet channel but no white noise level is measured on amplifier output.
4. Speakers are switched to IVU and muted.
e Case 10 - Invalid CTCSS tone signal received
1. Radio signal is received on valid IVU channel/frequency, but contains incorrect CTCSS tone.
2. Speakers remain connected to head unit at all times, with no interruption or muting of head unit.
e Case 11 - Weak Signal Received
1. Radio signal is received on valid IVU channel/frequency, with correct CTCSS tone, but signal strength weaker than calibrated squelch strength.
2. Speakers remain connected to head unit at all times, with no interruption or muting of head unit.
e Case 12 - Receive Calibration Radio Signal but invalid Head Unit Tone
1. Valid calibration radio signal is received by IVU.
2. Speakers remain connected to head unit at all times, with no interruption or muting of head unit.
e Case 13 - Higher-priority Message Begins Being Received Pre-conditions:
1. Normal Valid Signal Beginning to be Received, or
, 2. Normal Valid signal with first CTCSS tone marker, or
3. Normal Valid signal with second CTCSS tone marker.
4. Higher-priority message begins being received, with volume high enough to compensate for ambient noise detected on microphone.
Sequence of events:
1. A higher-priority valid radio signal is received by the IVU.
2. IVU recognises this high-priority message within 4 seconds, and IVU enters receiving message state.
3. Received higher-priority audio becomes audible on speakers, with volume high enough to compensate for ambient noise detected on microphone.
Use Case 14 - Power On with RF Circuit Fault
1. Power is switched on.
2. Speakers are immediately switched to head unit.
3. Radio receiver tunes to quiet channel and white noise level is measured on amplifier output.
4. Radio receiver tunes to internal UHF transmitter frequency, and white noise level is still measured on amplifier output.
5. Speakers are switched to IVU and muted.
Use Case 15 - Receive Data Message
1. FSK-modulated radio signal received by IVU
2. IVU demodulates FSK data.
3. IVU finds packet frame sync bytes.
4. IVU passes on data following frame sync bytes out of wired serial port.
Use Case 16 - Receive Data Message Without bit-sync and frame-sync bytes
1. FSK-modulated radio signal received by IVU
2. IVU demodulates FSK data.
3. IVU does not find packet frame sync bytes.
4. IVU does not pass on data following frame sync bytes out of wired serial port.
[00333] The final important portion of the apparatus and system of the present invention is the communications architecture.
[00334] This radio communications interface is for transmitting warning signals from rail infrastructure and trains to in- vehicle units (IVUs) located in road vehicles. It is a one-way interface, IVUs only ever receive communications using this interface. It is a direct point-to-point analogue and digital radio communications interface - there is no network or nodes which relay communications using this interface. All valid warning messages received by IVUs are passed to in-vehicle audio speakers in real time.
[00335] A UHF audio transmission is the preferred means by which to notify road vehicle operators of hazards because the transmission/broadcast:
1. is one way, no latency
2. range is adjustable and repeatable
3. can be directed
4. is unaffected by weather
5. does not require line of site
6. has spectrum allocation
[00336] The signal is a frequency-modulated UHF transmission, modulated with either a human understandable audio signal superimposed with a sub-audio CTCSS tone for switching purposes or modulated by a 2400bps FSK data stream.
[00337] The carrier may be any frequency in the range of 400 to 470MHz. The channels spacing is 12.5kHz.
[00338] It is envisaged that there will be separate frequency bands for various priority levels, e.g.:
1. Rail
2. Police
3. Emergency
4. Traffic warnings
[00339] The 433MHz ISM band is used internally within IVU receivers as a test signal on power-up, and is not used for any other purpose. This band covers 433.05 - 434.79MHz, and allows for up to 25mW of equivalent isotropically radiated power (EIRP) per transmitter.
Transmitters within the IVUs will be limited to ImW, and their antennas limited to PCB printed monopoles, or F-antenna types.
[00340] Carrier frequencies will be reserved for the PCU. ISM bands will not suffice for this purpose, as PCU's will be required to transmit power of the same order of magnitude as IVU warning transmitters (1 W) - too powerful to be deemed low interference potential devices (LIPDs).
[00341 ] As channels are separated by 12.5kHz, the bandwidth is also to be BT < 12.5kHz. Given a modulating signal bandwidth of 3kHz, this should be a maximum ~4.5kHz peak instantaneous deviation of the carrier frequency.
[00342] The audio baseband signal consists of a human-understandable 300Hz to 3kHz audio signal added to a 60Hz-260Hz CTCSS single-frequency tone. The preferred IVU
Communications Baseband Spectrum is illustrated in Figure 15.
[00343] The FSK baseband signal consists of the FSK signal only (no CTCSS). Figure 16 is an illustration of an IVU Communications Baseband Spectrum for an FSK data transmission.
[00344] Continuous Time-Coded Squelch System (CTCSS) is a continuous single-frequency sub-audio (67Hz-257Hz) tone added to the baseband audio signal. It is used in the IVU communications interface to indicate that a transmission is audio. An IVU will only open the squelch when it receives a signal with the correct CTCSS tone frequency for the carrier frequency and channel received.
[00345] CTCSS is not intended to provide comprehensive security against intended misuse of the IVU communications interface. In the current design, an attacker with a CTCSS-equipped UHF transceiver would be able to generate unauthorised IVU transmissions, which any IVUs within range will relay to speakers. In future versions a digitally-coded squelch system may be used, with additional encryption measures to securely prevent unauthorised misuse.
[00346] CTCSS tones of 50Hz, or multiples thereof, must not be used due to this being the mains power frequency, and possibly causing nuisance triggering of the squelch in IVUs.
[00347] A 71.9Hz CTCSS tone is used for PCU calibration signals. CTCSS is not used for FSK data transmissions.
[00348] The audio frequency ranges from 300Hz to 3kHz, and has arbitrary content (i.e. may be speech, sirens, chimes, or other messages as determined by human factors studies). If the audio content is a repeated message, the break between repetitions should be marked with a break in the CTCSS tone of no less than 0.2s. This allows receivers to only relay a complete message once, instead of continuously relaying the message as it repeats.
[00349] The 2400baud FSK signal uses two tones - 1200Hz and 2400Hz, with 1200Hz corresponding to "1" and 2400Hz corresponding to "0". To achieve the 2400 baud rate, a single logic 1 bit is indicated by a half wavelength of a 1200Hz sine wave and a single 0 bit is indicated by a full wavelength of a 2400Hz sine wave. The sine wave frequency always changes at the zero crossing of the wave.
[00350] The data transmission consists of at least two bit synchronisation bytes (two AA16), followed by two frame synchronisation bytes (C416 and D716), and then a payload of data bytes. The end of the data packet is indicated by either a loss of carrier or a loss of FSK modulation.
[00351 ] The content of the payload is beyond the scope of this document, and depends on the requirements of the rest of the GRSS system, including the in-vehicle computer to which the IVU passes-on data.
[00352] An IVU transmission consists of the following sequence (illustrated in Figure 17): 1.≥1 s of carrier wave modulated by CTCSS single tone only. This allows time for receivers to scan to carrier frequency, recognise CTCSS tone, and switch speakers to receiver before the start of the audio message. 2. Arbitrary time length of carrier wave modulated by audio message + CTCSS single tone, as long as required. 3.≥0.2s of unmodulated carrier wave only. This allows the receiver time to recognise loss of CTCSS tone and switch audio gain to zero before a white noise signal is relayed to the speakers.
[00353] An IVU transmission of a repetitive message consists of the following sequence (illustrated in Figure 18): 1.≥1s of carrier wave modulated by CTCSS single tone only. This allows time for receivers to scan to carrier frequency, recognise CTCSS tone, and switch speakers to receiver before the start of the audio message. 2; Arbitrary time length of carrier wave modulated by audio message + CTCSS single tone, as long as required. 3.≥0.2s of unmodulated carrier wave only. This marks the end of the message, and allows time for the receivers to quickly scan for other higher-priority messages. 4.≥0.2s of carrier wave modulated by CTCSS single tone only. This allows time for the scanning receivers to recognise that the message is about to restart. 5. Repeat steps 2 to 4 as many times as the message needs to be broadcast. 6.≥0.2s of unmodulated carrier wave only. This allows the receiver time to recognise loss of CTCSS tone and switch audio gain to zero before a white noise signal is relayed to the speakers.
[00354] The PCU transmission sequence is identical to the normal use transmission sequence, except the time length of the CTCSS tone has significance. The PCU is to cease the CTCSS tone the instant that the sound pressure level within the cabin meets specification. A preferred form is illustrated in Figure 19.
[00355] A data-only transmission may be useful in some situations. An IVU transmission of a data-only message consists of the following sequence (illustrated in Figure 20): 1.≥0.5s of carrier wave modulated by FSK idle tone. This allows time for receivers to scan to carrier frequency and recognise FSK idle tone before the start of the data message. The audio band signal should be the designated idle tone of FSK. 2. FSK data message. This should take as long as is required to transmit the arbitrary data message. 3.≥0.2s of carrier wave modulated by FSK idle tone only. This is enough time for a receiver to demodulate the end of the data before the carrier ceases.
[00356] A transmitter may arbitrarily transmit audio or data to IVUs as long as the transmission meets the following requirements: 1. For audio: a. The carrier must begin at least Is before the start of the analogue audio signal, to allow enough time for the scanning IVU to detect the carrier and CTCSS tone and switch speaker relays to the IVU. b. The designated CTCSS tone must begin and continue at least Is before the start of the audio transmission. This is required to ensure that scanning receivers have enough time to detect the transmission and recognise that it is a valid transmission, due to the valid CTCSS tone, and stay locked to that frequency. c. The CTCSS tone must cease at least 0.2s before the carrier ceases, so the IVU has enough time to detect the end of the message before a noise signal is sent to the vehicle's speakers. d. FSK data must not be present while the CTCSS signal is present. e. FSK data signal must cease at least 0.2s before the start of the audio message, or the end of the carrier. f. FSK data must not begin until at least 0.1 s after the designated audio CTCSS tone ends. 2. For data transmissions: a. The carrier must begin at least 0.5s before the start of the FSK data transmission, to ensure that scanning receivers have enough time to detect the transmission. b. The carrier should continue for at least 0.1s after the end of the FSK data so the IVU is able to decode to the end of the packet.
[00357] The following table includes the signal specifications for the IVU of the preferred embodiment.
Figure imgf000085_0001
Figure imgf000086_0001
[00358] The IVU will have a squelch opening threshold which can be configured from - 1 lOdBm to -45dBm, however -75dBm is the preferred and nominal setting.
[00359] As IVU receivers will contain their own internal helical linearly-polarised receiving antennas (with ~0dB gain) and will be installed behind the dashboards of road vehicles, the vehicles themselves will attenuate the IVU radiation significantly before it reaches the IVU receiver antenna.
[00360] Measurement trials have determined that there is 10-20dB attenuation from outside of the road vehicle to the internal receiving antenna. The result is an accepted threshold ambient power level of 50dBm.
[00361 ] Given the train-to- vehicle range of 1800m (and equivalent FSPL of 90dB), and the road vehicle exterior power of -50dBm, a transmitter power of 37dBm (5W) is required with ~2dBi antenna gain on the train.
[00362] Given the crossing-to-vehicle range of 800m (and equivalent FSPL of 83dB), and the road vehicle exterior power of -50dBm, a transmitter power of 30dBm (1 W) is required with ~3dBi antenna gain at the roadside unit.
[00363] The link budget has a surplus of 40dB to allow for excessively lossy road vehicle installations.
[00364] At type 2 and 3 crossings, the UHF antennas are configured to direct radiation along the roadways adjacent to the crossings for an effective distance of dWV to provide sufficient warning for oncoming road vehicles. Antennas and attenuators must be adjusted to provide at least the threshold far-field radiation level specified in section 3.5, within the desired warning zone alone these roadways. Care is taken during installation to minimise stray radiation to minimise nuisance IVU activation in cases such as road vehicles parked close to the level crossing. This is illustrated in Figure 21.
[00365] The IVU transmission is circularly polarised, as the IVU uses an internal linearly- polarised antenna with arbitrary orientation.
[00366] Appropriate circularly-polarised crossed Yagi-Uda directional antennas may be used to direct radiation along adjacent roadways. Two to six such antennas may be used, depending on the topology of the adjacent roads and intersections. This is illustrated in one form for a T intersection in Figure 22.
[00367] For type 2 and 3 crossings, a 600m warning range is required for cars, and 850m for trucks.
[00368] At type 1 crossings, the UHF antenna on the train transmits the IVU warning signals directly to passing road vehicles using an omnidirectional linearly polarised antenna (see Figure 23). An omnidirectional antenna must be used on the train to account for all road topologies and train configurations (i.e. Locomotives may be travelling in reverse).
[00369] The radiation levels emitted by the OBUs must also be high enough to ensure that when it is within the warning range of a type 1 crossing, that the adjacent roads all receive this minimum radiation level.
[00370] In order to provide sufficient warning for the worst case scenario of the road being parallel to the railway and a train and road vehicle moving in opposite directions (such as that illustrated in Figure 24), moving transmitters are to be calibrated to transmit at high enough power levels that irradiance of 50dBm is received at a distance of dWT+ dWV= 2km.
[00371 ] rVUs contain an internal linearly-polarised antenna. As the transmitted signal is circularly polarised, the IVU may be arbitrarily oriented within a vehicle. [00372] A PCU is to transmit at power levels which produce the specified threshold ambient radiation levels upon the outside of the road vehicle, that a vehicle would experience entering a warning zone. An IVU then saves this received radiation level as its squelch opening threshold.
[00373] The following table includes the radiation specifications for the IVU of the preferred embodiment.
Figure imgf000088_0001
Figure imgf000089_0001
[00374] In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.
[00375] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

Claims

CLAIMS 1. A radio break-in apparatus including an in-vehicle unit associated with a member vehicle in a first category, the in vehicle unit adapted to be connected between an existing vehicle stereo head unit and vehicle speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a radio break-in signal, an internal transmitter for transmitting a signal, and at least one processor peripheral interface, an on-board unit associated with a member vehicle in a second category, the on-board unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the
microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly a roadside unit associated with at least one piece of fixed transport infrastructure, the road side unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the
microcontroller implements instructions to actuate a change in the fixed transport infrastructure based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly wherein when a member vehicle in a second category approaches a piece of fixed transport infrastructure with a roadside unit, the onboard unit issues a radio transmission to the roadside unit which upon receipt of the radio transmission, actuates a change in the mode of the fixed transport infrastructure to indicate the approach of a member vehicle in a second category and the roadside unit broadcasts a radio break-in transmission which when received by an in-vehicle unit of a member vehicle of the first category, the processor interrupts a normal signal from the existing vehicle stereo head unit to the vehicle speakers, and issues a warning message to vehicle speakers.
2. A radio break-in apparatus including an in-vehicle unit associated with a member vehicle in a first category, the in vehicle unit adapted to be connected between an existing vehicle stereo head unit and vehicle speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a radio break-in signal, an internal transmitter for transmitting a signal, and at least one processor peripheral interface, an on-board unit associated with a member vehicle in a second category, the on-board unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the
microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly wherein when a member vehicle in a second category approaches a piece of fixed transport infrastructure, the onboard unit broadcasts a radio break-in transmission, which when received by an in- vehicle unit of a member vehicle of the first category, the processor interrupts a normal signal from the existing vehicle stereo head unit to the vehicle speakers, and issues a warning message to vehicle speakers.
3. A radio break-in apparatus as claimed in claim 1 or claim 2 wherein a radio break-in
transmission is issued to a member vehicle of the first category, from active infrastructure or from an on-board unit in a directed manner, and/or from the active infrastructure or on-board unit as a broadcast radio break-in transmission.
4. A radio break-in apparatus as claimed in any one of the preceding claims wherein the at least one GPS receiver and transceiver of the member vehicle of the second category is associated with a computer processor preloaded or having access to location information of all infrastructure within the system, whether fixed infrastructure or mobile infrastructure and/or member vehicles of the second category including itself.
5. A radio break-in apparatus as claimed in claim 4 wherein updating of relative positions of infrastructure and/or member vehicles within the system occurs via a real time link such that the positions of infrastructure and/or member vehicles are represented in real time.
6. A radio break-in apparatus as claimed in claim 4 or claim 5 wherein the processor registers or calculates the position of member vehicles relative to each other and/or other elements of infrastructure, in particular fixed infrastructure where changes in mode of operation are required or mobile infrastructure where collision avoidance is required.
7. A radio break-in apparatus as claimed in any one of the preceding claims wherein the onboard unit issues a radio transmission to transport infrastructure dependent upon proximity of an approaching member vehicle.
8. A radio break-in apparatus as claimed in any one of the preceding claims wherein the
locating device on each member vehicle identifies in real time, a position of the member vehicle and an on board unit is configured to calculate distance, approach velocity and time of a member vehicle of the second category to any transport infrastructure, and transmit a signal once the member vehicle crosses a point at a predetermined time from the transport infrastructure.
9. A radio break-in apparatus as claimed in any one of the preceding claims wherein if a
directed signal is transmitted and the signal is directed at the transport infrastructure, the signal triggers a response from the infrastructure which in the form of a return signal or a change of mode of operation of the transport infrastructure.
10. A radio break-in apparatus as claimed in any one of the preceding claims applied to a Type 1 , low risk level crossing, and an on-board unit of a rail vehicle is provided with the location of the level crossing and upon approach, broadcasts a radio transmission once within a particular warning distance of the level crossing, said radio transmission received by any in- vehicle units of member vehicles within range.
11. A radio break-in apparatus as claimed in any one of the preceding claims applied to a Type 2, medium risk level crossing and an on-board unit of a rail vehicle is provided with the location of the level crossing and upon approach, within a particular warning distance, the onboard unit issues a directed radio transmission to the roadside unit in order to ascertain the status of the roadside unit, if the status of the roadside unit is active, the roadside unit confirms this by return transmission to the on-board unit and also transmits a targeted or directed radio transmission to relevant member vehicles and if the roadside unit is not active, no return transmission is issued and the on-board unit issues a broadcast radio transmission which can be received by in vehicle units of member vehicles within range.
12. A radio break-in apparatus as claimed in any one of the preceding claims applied to a Type 3, high risk level crossing provided with a roadside unit, an on-board unit of a rail vehicle is provided with the location of the level crossing and upon approach within a particular warning distance, the onboard unit issues a directed radio transmission to the roadside unit in order to ascertain the status of the roadside unit, if the status of the roadside unit is active, the roadside unit confirms this by return transmission to the on-board unit and also transmits a targeted or directed radio transmission to relevant member vehicles and if the roadside unit is not active, no return transmission is issued and the on-board unit issues a broadcast radio transmission which can be received by in vehicle units of member vehicles within range with the additional step that the transmission from the on-board unit to the roadside unit activates the automated crossing infrastructure if the status of the roadside unit is active and if the roadside unit is not active no return transmission is issued and the onboard unit issues a broadcast radio transmission.
13. A radio break-in apparatus as claimed in any one of the preceding claims wherein the onboard unit includes at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
14. A radio break-in apparatus as claimed in any one of the preceding claims wherein each of the in vehicle units fail to safe when an electronic or mechanical failure occurs and if the in vehicle unit fails, the radio speakers fail, to notify failure to an occupant of the vehicle.
15. A radio break-in apparatus as claimed in any one of the preceding claims further including at least one personal device unit into earphone sets or directly into personal devices which include one or more speakers for use in pedestrian circumstances where pedestrians are placed in high risk areas such as pedestrian level crossings.
16. An in-vehicle unit for a radio interruption system, the unit adapted to be connected between an existing vehicle stereo head unit and vehicle's speakers and between the existing vehicle stereo head unit and vehicle power supply, the unit including a processor, an internal receiver for receiving a signal, an internal transmitter for transmitting a signal, at least a pair of audio switching relays, a first switching relay to switch both positive and negative speaker outputs between the vehicle head unit and a first set of vehicle speakers and a second switching relay to switch only positive speaker outputs between closed and open for the vehicle head unit and a second set of vehicle speakers, and at least one processor peripheral interface wherein when the unit receives a warning message, the processor interrupts a normal signal from the existing vehicle stereo head unit to all of the vehicle speakers, and directs the warning message to the first set of vehicle speakers.
17. A multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the
microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly or implements instructions based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly, based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
18. An on board unit for a moving vehicle, the on-board unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the microcontroller stores instructions and the microcontroller implements instructions to issue a radio transmission to a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
19. A road side unit for use with fixed transport infrastructure, the road side unit including at least one multipurpose printed circuit board assembly including a microcontroller with data storage, at least one data medium reader, at least one radio audio and data communications transceiver with antenna, at least one GPS receiver, at least one general packet radio service transceiver and at least one power supply port wherein the data storage of the
microcontroller stores instructions and the microcontroller implements instructions to actuate a change in the fixed transport infrastructure based on the receipt of a radio transmission issued from a second remote multipurpose printed circuit board assembly based on the location of the first multipurpose printed circuit board assembly relative to the second remote multipurpose printed circuit board assembly.
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WO2018013272A1 (en) * 2016-07-12 2018-01-18 Siemens Industry, Inc. A connected vehicle traffic safety system and a method of predicting and avoiding crashes at railroad grade crossings
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DE102019216770A1 (en) * 2019-10-30 2021-05-06 Siemens Mobility GmbH Warning procedure and processing facility for a level crossing system
CN114205327A (en) * 2021-12-28 2022-03-18 卡斯柯信号有限公司 Dynamic IP communication method and system for trackside security platform
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