TW201927012A - A circuit for limiting the emissions of a cellular tracking device - Google Patents

Abstract

A cellular tracking device (107) comprising a communication module (109), an antenna module (108) and a circuit (105) for limiting the emissions of a tracking device (107), said circuit (105) comprising: a connection input (1050) for connecting to a communication module (109) of the tracking device (107); an output connection (1051) for connecting to an antenna module (108) of the tracking device (107); a guard circuit (103) for periodically interrupting an emission of an output signal at the output connection, thus preventing the tracking device (107) to continuously transmit; a signal limiter (106) for trimming said output signal (o) when the power of said output signal exceeds a predefined threshold.

Description

Circuitry for limiting the emission of a cellular tracking device

The present disclosure relates to a circuit for preventing radio transmission activity of a cellular tracking device from interfering with an avionics device on an aircraft.

With the advent of the Internet of Things and the decline in hardware prices, any type of consignment is increasingly being tracked.

Delivery companies and customers who ship consignments (such as parcels or containers) often need to know where the consignment is located at a particular moment. This message improves the visibility of the shipping service, for example, to determine the expected arrival of the consignment, and to determine shipping issues early. For the customer, the actual location of his consignment gives him a better understanding of whether the consignment is on the way, on the right path, and when it will arrive. The existing solution can even send a message about the status of the consignment, such as its temperature or whether it has been turned on, and is able to receive an alarm when the deviation occurs.

Therefore, a consignment tracking/trace system has been created. For example, existing container tracking systems provide a unique code for each container that is scanned at certain checkpoints. The position of the container is determined based on the position of the checkpoint. For example, the unique codes are scanned by a barcode scanner or automatically scanned by an RFID scanner. However, this solution has the following drawbacks, all checkpoints must be equipped with a scanner, and the current determination of the container position is dependent on the availability of such checkpoints, which is limited. In addition, the location of the container can be accurately known only after the scan has been completed. In particular, once the container is on a vehicle, its location is continually unknown until the next station from which the container was unloaded is scanned. Therefore, there is no available location information during transit time within the same vehicle. For example, the information that the container has been sent by the wrong means of transportation is only available at the next checkpoint.

Other tracking services provide a Global Positioning System (GPS) tracking device for each shipment. The GPS provides the GPS tracking device with a location of the consignment with very high precision. GPS has the disadvantage of being able to determine the location only with the GPS tracking device; therefore, if the user or the location processing system is located at a remote location, an additional link is needed to pass the location to the user. Furthermore, the GPS signal is weak and is generally not available when the interior of the building or the interior of the vehicle is blocked. The battery autonomy is usually limited.

Alternatively, the location can be determined using Wi-Fi signals and possibly triangulation. This solution works only if the consignment is within reach of one or more hotspots and only if the location of the hotspots is known.

Applicants and other companies have also proposed honeycomb tracking devices. These devices use a cellular transceiver such as a GSM module to determine the location of the device based on the location of the nearest base station and possibly based on triangulation and to transmit the location to a remote server. Due to the ubiquity of cellular networks, these devices offer extended coverage both indoors and outdoors. This autonomy is very important, especially if the cellular tracking device does not have a display and emits intermittently.

An important disadvantage of such cellular tracking devices is that they are not allowed to transfer their position from the aircraft, as it is well known that cellular devices can interfere with nearby avionics control devices and change their functionality.

Therefore, according to the flight regulations, these devices, and more generally all transmitting personal electronic devices (T-PEDs), are required to have their transmitters turned off unless they are proven to be harmless to the aircraft and if the operator allows these Device. Failure to do so would endanger the safety of the aircraft and lead to serious consequences.

According to the European Union Aviation Agency Rules Jar Ops 1.110 "The operator must not allow anyone to use it and take all reasonable steps to ensure that no one will use the mobile electronic device that would adversely affect the aircraft's systems and equipment." The provisions for the performance of avionics for aircraft are defined in the document "RTCA DO-160 Environmental Conditions and Test Procedures for Airborne Equipment".

A solution for preventing the use of a mobile phone in an aircraft has been proposed, and a system and method for shielding a GSM signal within an aircraft is proposed in US2014364053. This signal obscuration is not approved in many countries and may in fact cause additional interference to electronic equipment in the aircraft. This will also make it impossible for the aircraft to use the GSM tracking device.

FR 2 985 114 B1 discloses a mobile phone comprising a first high power RF transmitter and a second reduced power RF transmitter, the second reduced power RF transmitter being activated to replace the high power RF transmitter to reduce the aircraft from interference. The mobile phone provides limited communication capabilities even in sensitive areas where communication is usually not allowed. However, safety depends on what the user needs to do when entering the aircraft. Furthermore, having two RF circuits increases the cost and size of the device.

EP 1966 906 B1 discloses a method and apparatus for communicating at reduced power. The method includes transmitting a request to a base station to establish a low power transmission. As such, security is dependent on the user's prudent operation.

Other solutions have been proposed to automatically shut down personal electronic devices in aircraft. Some solutions use accelerometers, others use motion sensors, while others sense aircraft proximity.

EP 1 287 376 describes several means of sensing the approach of an aircraft, including sensing the transponder of the aircraft, sensing the acoustic waves formed by the injection engine, sensing the pressure flight characteristics, detecting the position with GPS and comparing the position to a known airport. Position, detect tags around the aircraft (for example, beacons). However, these solutions require multiple sensors to operate reliably, so redundancy is required to reliably shut down, and thus the cost of the device is increased and a large number of batteries are used. In addition, most of the solutions in this document are too late to shut down the communication module when the aircraft is already flying in the air.

WO2011063285 describes an acceleration-based detection method. However, the solution described requires a power-consuming 3-axis accelerometer. Furthermore, the solution describes the detection of flight phases with "sufficient vertical acceleration". However, in this case, the aircraft is already flying in the air, and therefore the detection occurs too late.

WO2013044399 describes a detection method based on acceleration data. However, by doing so, it is first necessary to reliably characterize the vibration of the aircraft, and these features can only be used in a limited set of aircraft that have been tested. Or, once the vibration is detected, the tracker can be turned off. However, in this case, the tracker will not communicate when moving outside the aircraft.

WO 20130245986 describes a solution that expresses the characteristics of a flight by continuously collecting athletic data and comparing the athletic data with typical vehicle movements. However, it is difficult to positively determine whether the detected motion is produced by an aircraft; this method is not considered to be reliable.

US2016260058 discloses a method involving monitoring goods. The method uses an accelerometer device and can include adaptation of the transmit power.

US20140308940 describes a solution for switching the operating mode of a mobile phone based on the detected pressure and comparing it to a typical aircraft air pressure. However, this solution requires a precise representation of the characteristics of the cabin pressure of all aircraft. In addition, this solution does not apply to unpressurized aircraft or helicopters.

In general, these solutions have several drawbacks.

The main thing is that these solutions depend on the environment in which they are located and may not be able to detect takeoffs reliably and early enough. For example, an accelerometer may not be able to detect a smooth takeoff or helicopter takeoff. HF environmental sensors may be surrounded by materials that cause signal strength degradation, so aircraft proximity cannot be detected.

Another disadvantage of these solutions is that they require several additional components that increase the final cost of the device and may increase the energy consumption of the device.

It is an object of the present invention to provide an apparatus and method that overcomes the above-discussed problems of the prior art.

In particular, it is an object of the present invention to provide a cellular tracking device that does not adversely affect the airworthiness of any aircraft, such as an aircraft or helicopter.

Preferably, the security of the tracking device is independent of any sensors.

In accordance with the present invention, these objects are achieved in a circuit for limiting the transmission of a cellular tracking device, the circuit comprising:
a connection input for connecting to a communication module of the cellular tracking device;
An output connection for connecting to an antenna module of the cellular tracking device;
a protection circuit for authorizing or interrupting the transmission of an output signal to prevent the cellular tracking device from continuously transmitting signals;
A signal limiter for trimming the output signal threshold when the power of the output signal exceeds a predetermined threshold.

In this application, we define a "honeycomb tracking device" as a device whose primary function is to track an item or a person, and in which the location of the item and the transmission of the location to a remote device are based on a A cellular network, such as a GSM network or similar network.

The circuit is the output of a communication module that is to be connected to a cellular tracking device. It prevents the cellular tracking device from being launched in a manner that may interfere with the avionics. Due to the combination of the signal limiter (used to avoid a strong signal being sent out) and the protection circuit (used to prevent constant or other irregular transmissions), it is ensured that the device will never be transmitted strongly or continuously enough to become The aircraft is dangerous.

The circuit is preferably a discrete circuit comprising one or more electronic components different from the communication module. Therefore, the security depends only on this circuit and is not related to the communication module.

Therefore, only this circuit needs to be certified to be authorized on the aircraft.

The protection circuit is preferably adapted to authorize or block the transmission of the output signal in accordance with an authorized transmission pattern.

In one embodiment, the protection circuit is adapted to authorize transmission of the output signal during a first predetermined interval of each of the plurality of cycles, and for a remaining time period in each of the equal periods The emission of the output signal is blocked internally.

The protection circuit can include a set of components to block transmission during periods of undesired transmission cycles.

The protection circuit can include another set of components to block transmissions in certain frequency bands.

In one embodiment, the signal limiter circuit includes two Zener diodes that are mounted in parallel in opposite directions between the output of the power amplifier and the ground signal. The breakdown voltage of the Zener diode is chosen to limit the maximum power that can be generated to a level below that that should not be exceeded according to flight regulations.

The signal limiter continually applies an output signal to the power amplifier and is independent of any external sensor signals. Since it cannot be controlled by software, the authentication of the device does not require any software certification.

The power amplifier is preferably mounted downstream of the protection circuit and upstream of the signal limiter.

The power amplifier and the signal limiter can be integrated into one circuit.

A cellular tracking device can include a first set of electronic components including the communication module and the antenna module. The emission limiting radio circuit preferably includes a second set of electronic components that are different than the components of the first group.

The power amplifier can include a configurable amplification factor. This amplification factor can be controlled by the communication module and is preferably configured in such a way that the output power of the power amplifier never exceeds the level that would affect the airworthiness of the aircraft.

The communication module can further include a protocol controller for controlling signal transmission. The protocol controller can be synchronized with the protection circuit to avoid transmissions during the blocking window and to ensure that signal cancellation performed by the protection circuit does not interrupt the signal in the middle of an active frame.

Detailed description of the preferred embodiment

FIG. 1 shows an example of a cellular tracking device 107.

In a first embodiment, the cellular tracking device 107 can be a mobile phone of a tracked person. For example, parents will be interested in tracking children who travel alone.

In another embodiment, wherein one of the items is, for example, a container, a shipping container, or any other consignment that needs to be tracked, the cellular tracking device 107 is preferably enclosed within the item and connected to the item in any manner. An item, or a special device attached to the item, such that the tracking device 107 can be associated with the item. In this embodiment, the tracking device 107 is preferably a silent device, such as a device that can only transmit or receive data without sound. Therefore, it preferably does not have any keyboard, speaker, microphone and/or display.

In one embodiment, buttons, a small display or LEDs, and/or a speaker are available to provide a limited user interface for configuration and settings. Alternatively or additionally, a remote device connected to the tracking device can be connected to and/or displayed through a wireless interface, such as a smart phone or a computer, for example, a wireless interface. Wi-Fi, Bluetooth, ZigBee or NFC. In one embodiment, the tracking device can be in the form of a credit card.

The following description will focus on this embodiment of a cellular tracking device 107 for tracking items (e.g., consignments).

In one embodiment, the tracking device 107 includes a communication module 109, a circuit 105 (eg, a transmission limiting radio circuit 105), and an antenna module 108.

The communication module 109 is for collecting information about the available radio network 110 and performing communication tasks with the radio network 110. The communication module 109 is, for example, a receiver for Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), etc., or is suitable for use with a radio network (eg , cellular network 110) any other electronic module that establishes a data connection.

The tracking device 107 can establish communication via the radio network 110, such as a call, text message (eg, SMS), GPRS, special system message, broadcast message, or any other message or communication sent over the radio network 110. .

The communication module 109 includes logic, circuitry, and/or code operable to transmit, receive, encode, and decode radio signals in accordance with one or more radio communication standards and/or protocols, for example, the one or more Radio communication standards and/or protocols are a standard for radio communication with mobile phones, such as GSM, UMTS, LTE. The communication module 109 can be further configured to establish a connection with the radio network 110.

The communication module 109 includes a battery (not shown), a microcontroller 100, a baseband controller 101, and a protocol controller. The microcontroller 100 includes or is coupled to a memory for storing, for example, an operating system such as Unix or Android, and a plurality of software modules executable by the microcontroller. A software module can be provided to collect information about the antennas detectable from the cellular network. This information may include, but is not limited to, antenna identification code, antenna location, network type, antenna frequency, signal power, and signal delay. Another software module can be provided to communicate this information over the radio network 110 to a remote server or device.

The baseband controller 101 includes appropriate logic, circuitry, and/or code to establish communications with the radio network 110.

Additionally, the tracking device 107 can include sensors to monitor the tracked items, such as temperature sensors, accelerometers, humidity sensors, and the like (not shown). Some of the sensors and other sensors (such as clocks or light sensors) can be used to wake up the device depending on the measured signal, and/or to switch the device to a Low power no emission mode.

Additionally, the tracking device 107 can include radio signal receiving circuitry for other signals such as Wi-Fi, Bluetooth, Zigbee, GPS, and the like. Information about such signals can be collected by the radio network 110 and sent to a remote server.

The antenna module 108 is any circuitry for connecting the transmit-restricted radio circuit 105 and an antenna 111, and can include operable to transmit radio frequency signals from the radio network 110 and to transmit radio frequency signals to the radio network 110. Appropriate logic, circuitry, and/or code that are not amplified.

The emission limiting radio circuit 105 is an additional circuit connected between the communication module 109 and the antenna module 108. It may include one or more discrete electronic components different from the (etc.) components that form the communication module 109 and the antenna module 108.

One function of the transmit-limited radio circuit 105 is to prevent over-specified transmissions through the antenna 111, such as regulations used in aircraft.

The emission limiting radio circuit 105 is preferably a single hardware component or a set of components on a printed circuit board. All components can be made only by analog circuits. Alternatively, at least some of these components include digitally controlled analog circuits.

The transmit limiting radio circuit 105 preferably includes a connection input 1050 for connecting it to the communication module 109 and a connection output 1051 for transmitting its output signal o to the antenna module 108. For example, the input and/or the output can include pins for soldering the circuit 105 to a printed circuit board.

In a preferred embodiment, the emission limiting radio circuit includes a protection circuit 103, a power amplifier 104, and a signal limiter 106.

The protection circuit 103 can ensure that the cellular tracking device 107 can only transmit during a time limited transmission window, for example according to a duty cycle (e.g., 1 second per hour) or according to a predefined pattern. This will ensure that the cellular tracking device 107 will never transmit in a continuous mode. In a preferred embodiment, the protection circuit 103 authorizes the outgoing signal during a first predetermined interval of each of the plurality of cycles, and for a remaining time period in each of the equal periods Blocking the emission of the output signal. For example, the protection signal authorizes transmission of the outgoing signal o for less than 2 minutes per hour or preferably less than 30 seconds per hour, and blocks the outgoing signal for the remainder of the time. The period authorized to transmit is chosen to establish a connection with the closest base station and send a message.

The authorized period is preferably longer than one minute, preferably longer than five minutes, such as one hour. This will ensure that the tracking of the item is sufficiently detailed to meet most of the requirements while minimizing the period of launch. Other duty cycles and other non-periodic patterns of authorization/blocking may also be considered.

The protection circuit 103 can also ensure that the tracking device 107 can only transmit in one of a plurality of authorized frequency bands (eg, for GSM: 850 MHz, 950 MHz, 1800 MHz, and 1900 MHz). It may include a bandpass filter to filter all signals outside of the (equal) authorized band.

The power amplifier 104 is coupled to the output of the protection circuit 103 and amplifies the signals authorized by the protection circuit 103. The power amplifier is thus mounted downstream of the protection circuit 103 and upstream of the signal limiter 106. Since the protection circuit 103 blocks transmission most of the time, the power amplifier can consume power only for a short period of time.

The signal limiter 106 is coupled to the output of the power amplifier 104. It is preferably composed of analog electronic components.

Even if the communication module 109 is intended to transmit above this level in conjunction with the power amplifier 104, the signal limiter 106 prevents transmissions above an authorized level. Therefore, the signal limiter ensures that the power signal transmitted from the power amplifier 104 to the antenna module 108 never exceeds the maximum power that the aircraft has been authenticated, and the antenna module 108 then transmits its power to the antenna 111. . The maximum authorized power may, for example, cause the amplitude of the electric field generated by the antenna to be less than a predetermined threshold, such as 1 V/m.

The signal limiter 106 and the power amplifier 104 can be combined into a single amplifier whose transmit power is limited to a threshold. This is advantageous because power wasted caused by first amplifying the signal and then trimming the signal in subsequent signal limiter 106. This will also ensure that the signal limiter 106 does not distort the signal transmitted to the antenna 111. However, a separate signal limiter is safer and easier to authenticate than an amplifier with the largest transmit power.

In an alternate embodiment, the power gain is controlled by the baseband controller 101 and is configured to limit the power gain of the power amplifier 104 to below a threshold. This is also advantageous because it avoids wasting power and avoids signal distortion.

Moreover, the protection circuit 103 ensures that only authorized signals are provided to the input of the power amplifier 104. The security is therefore irrelevant to the communication module 109 and the power amplifier 104. Therefore, only certain of the transmission limiting circuits 103 and 106 require verification and/or authentication to authorize the use of the device on the aircraft.

The transmit limited radio circuit 105 only needs to block the outgoing signal; the signal received by the antenna module 108 can be relayed to the communication module without any interruption and is independent of the frequency band. Therefore, even during the period in which the transmission is blocked, it is possible to receive information about the available antennas used to determine the position of the device 107 and store the information. Thus, the incoming signal bypasses the transmit limited radio circuit 105 and is transmitted directly from the antenna module 108 to the communication module 109, as shown by the lines in the figure.

The authorization pattern of the protection circuit 103 (i.e., the ratio between the blocking period and the grant period) may vary and adapt, for example, depending on the intended use or depending on the signal received by the sensor or the signal received over the radio network. In one example, when the signal from the sensor or from the remote server indicates that the tracking device is likely to be on the aircraft, the duty cycle can be reduced such that the transmission time during each period is limited, And when the tracking device is less likely to be on the aircraft and/or when the tracking device approaches the delivery location and/or when other events are detected, the duty cycle is increased to transmit more frequently. It is also possible to trigger a change in duty cycle from a remote server or administrator. Alternatively, a button on the device 107 can be used to initiate an on-demand transmission.

During a typical communication cycle, the communication module 109 will require its baseband controller 101 to establish communication with the network in accordance with the protocol specifications. The protection circuit 103 monitors the transmission signal and controls the signal to be transmitted in accordance with an agreement in time; signals outside the authorized transmission window are suppressed.

If the protection circuit 103 has decided to block its output signal from being transmitted to the power amplifier 104, it will perform this blocking for a period of time (e.g., 1 hour) to ensure, for example, that even if the plurality of cellular tracking devices 107 are inside the same aircraft. At the time, the radio energy level remained at a very low level.

The protocol controller 102 is preferably synchronized with the protection circuit 103 to avoid attempting to transmit during the blocking window and to cause signal blocking performed by the protection circuit to avoid signal interruptions in the middle of an active frame.

The signal at the output of the protection circuit 103 is amplified by the power amplifier 104. The signal limiter 106 will trim any emission beyond a predetermined level downward, thus ensuring that the transmission does not adversely affect the aircraft. Moreover, the signal o is transmitted by the antenna module 108 to the radio network 110.

This embodiment has the advantage that the cellular tracking device 107 will always communicate according to the agreed standard and the sensitivity level below any critical component of the aircraft. This makes the cellular tracking device harmless to any aircraft and therefore can generally be certified for use on any aircraft.

Another benefit is that security is ensured only by the protection circuit 103 and the signal limiter 106. These circuits are relatively simple and their authentication is much easier than the authentication of a complete communication module 109.

Another advantage is that the receive path of signals from the antenna module 108 to the communication module 109 is not degraded. The signal limiter 106 has an effect only when there is a high power signal and has a negligible effect on the sensitive input signal present in the receive path. The protection circuit 103 does not interfere with the receiving path at all.

Another benefit is that the protection circuit 103 and the signal limiter 106 are permanently turned on and do not depend on the sensor. Therefore, they do not represent the risk of delay detection, such as critical airworthiness of the relevant flight phase.

An additional advantage of this embodiment is that if the aircraft is equipped with a communication access point (e.g., a GSM pico-cell), the cellular tracking device 107 will be able to communicate with the access point.

In another embodiment, the transmission is controlled by the protocol controller 102. In order to avoid that the protection 103 is always activated, the GSM baseband controller 101 will be manipulated by the protocol controller 102. The protocol controller 102 can be a software module.

100‧‧‧Microcontroller

101‧‧‧Base frequency controller

102‧‧‧Agreed controller

103‧‧‧Protection circuit

104‧‧‧Power Amplifier

105‧‧‧Emission limiting radio circuit

106‧‧‧Signal limiter

107‧‧‧Hive Tracking Device

108‧‧‧Antenna module

109‧‧‧Communication module

110‧‧‧radio network

111‧‧‧Antenna

1050‧‧‧Connect input

1051‧‧‧Connected output

o‧‧‧Output signal

The invention will be more fully understood by the description of the embodiments illustrated by the example illustrated in FIG.

Claims (11)

A circuit for limiting the emission of a cellular tracking device, comprising: a connection input for connecting to a communication module of the tracking device; An output connection for connecting to an antenna module of the tracking device; a protection circuit for authorizing or interrupting transmission of an output signal of the output connection, thereby preventing the tracking device from continuously transmitting; A signal limiter is configured to trim the output signal when the power of the output signal exceeds a predetermined threshold. The circuit of claim 1, the protection circuit being a type of protection circuit configured to authorize respectively to block transmission of the output signal in accordance with an authorized emission pattern. The circuit of claim 2, the pattern protection circuit configured to authorize transmission of the output signal during a first predetermined interval of each of the plurality of cycles, and in each of the cycles The emission of the output signal is blocked for the remainder of the time. The circuit of claim 1, which is composed of one or more electronic components, and the input connection and the output connection are formed by pins. The circuit of any one of claims 1 to 4, the protection circuit being further adapted to authorize transmission of a signal within a range of a predetermined frequency band and to block transmission of any signal outside the range of the predetermined frequency band. The circuit of any one of claims 1 to 5, wherein the signal limiter comprises two Zener diodes in opposite directions between the line transmitting the output signal and the ground signal Parallel mounting, wherein the Zener diode's breakdown voltage is selected to limit the maximum power that it can transmit. A circuit as claimed in any one of claims 1 to 6, comprising a power amplifier for amplifying the output signal, the power amplifier being mounted downstream of the protection circuit and upstream of the signal limiter. The circuit of any one of claims 1 to 7, comprising a power amplifier, the power amplifier and the signal limiter being integrated into a discrete circuit. A honeycomb tracking device comprising: a communication module; a circuit according to any one of claims 1 to 7; An antenna module. The cellular tracking device of claim 9, the communication module comprising a first set of electronic components, and the circuit comprising a second set of electronic components different than the components of the first set. The cellular tracking device of any one of claims 9 to 10, further comprising a protocol controller for controlling signal transmission, The protocol controller is synchronized with the protection circuit to avoid transmissions during the blocking window and to ensure that signal cancellation performed by the protection circuit does not interrupt the signal in the middle of an active frame.