GB2453001A

GB2453001A - Article tracking device that is less susceptible to detection

Info

Publication number: GB2453001A
Application number: GB0803782A
Authority: GB
Inventors: Russell Faulkner; John Hyde
Original assignee: PAY PER MILE Ltd
Current assignee: PAY PER MILE Ltd
Priority date: 2007-09-21
Filing date: 2008-02-29
Publication date: 2009-03-25
Also published as: GB0718394D0; GB0803782D0

Abstract

A global navigation satellite system GNSS tracking unit is disclosed comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter adapted to transmit at least location data relating to the unit to a remote receiver, wherein the transmitter is provided with a controller linked to at least one sensor, and wherein the controller operates to cause the transmitter to transmit when the at least one sensor detects a predetermined event, but to refrain from transmitting at other times so as to hinder detection of the tracking unit by unauthorized monitoring of transmitted signals. In a further embodiment, the transmitter is arranged to transmit at pseudorandom time intervals which may be spaced from each other by at least 5 minutes.

Description

I

IMPROVEMENTS RELATING TO ARTICLE TRACKING

TECHNICAL FIELD

The present invention relates to article tracking systems that are designed so as not to be easily locatable by thieves, thereby helping to reduce the risk of a tracking system being disabled prior to or just after theft of an article.

BACKGROUND

Tracking of valuable assets by methods such as GPS (Global Positioning System) and other GNSS (Global Navigation Satellite System) equivalents coupled with radio transmission of the location is now well established. Unfortunately this establishment has lead to the availability of sniffer systems designed to locate GNSS tracking devices mounted on or in the assets in order to remove or disable the tracking devices.

With any radio transmission system, its RF (radio frequency) emissions can be detected while the device is transmitting and may even be detected while on standby if fugitive emissions from such as the local oscillator are allowed to escape.

Accordingly, there is a need to provide GNSS tracking devices and systems that are less susceptible to detection by sniffer systems.

BRIEF SUMMARY OF THE DISCLOSURE

According to a first aspect of the present invention, there is provided a global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter adapted to transmit at least location data relating to the unit to a remote receiver, wherein the transmitter is provided with a controller linked to at least one sensor, and wherein the controller operates to cause the transmitter to transmit when the at least one sensor detects a predetermined event, but to refrain from transmitting at other times so as to hinder detection of the traddng unit by unauthonsed monitoring of transmitted signals.

The sensor may comprise a movement or motion sensor, which may be configured to sense movement of the tracking unit and/or the article itself, and/or to sense movement of external objects (such as persons or vehicles) within a predetermined zone or volume in the vicinity of the tracking unit When configured to detect movement of the tracking unit or article itself, the sensor may include a tilt switch (for example, a mercury switch) and/or a vibration sensor. When configured to detect movement of external objects, the sensor may include a motion sensor such as a passive infra-red (PIR) or sonar or other motion detecting sensor.

The tracking unit is preferably mounted on an article to be protected. The at least one sensor may also be mounted on the article to be protected, either together with the tracking unit or at another location on the article. Alternatively or in addition, the at least one sensor may be located off the article, for example on a gantry or building or the like in the general vicinity of the article.

In this way, the tracking unit can be configured not to transmit (and therefore not to reveal its presence to thieves) except when the article to which the tracking unit is attached is actually being stolen or about to be stolen.

Furthermore, the controller may be configured so as only to respond to the sensor at predetermined times or in predetermined conditions. For example, the controller may be programmed to ignore the sensor during predetermined time periods. An article to be monitored by the tracking unit may, for instance, be a vehicle such as a digger or bulldozer which is left on a construction site overnight In this situation, the controller can be programmed to ignore motion during working hours, but to act on detected motion at nights or weekends when it is known that the vehide should not be in use.

Advantageously, the controller is additionally configured to cause the transmitter to transmit at predetermined or random or pseudorandom intervals, preferably at least 5 minutes apart. This allows a location of the tracking unit to be monitored over time so as to ensure that it has not moved, or been moved without authorisation, while still reducing the chances of the tracking unit being found or identified by a passing sniffer device.

According to a second aspect of the present invention, there is provided a global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter adapted to transmit at least location data relating to the unit to a remote receiver, wherein the transmitter is provided with a controller configured to cause the transmitter to transmit at pseudorandom time intervals, preferably spaced from each other by at least 5 minutes, but to refrain from transmitting at other times so as to hinder detection of the tracking unit by unauthorised monitoring of transmitted signals.

According to a third aspect of the present invention, there is provided a method of article tracking wherein an artide to be tracked is provided with a global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter, wherein the transmitter is provided with a controller linked to at least one sensor, and wherein, upon detection by the sensor of a predetermined event, the controller causes the transmitter to transmit at least location data relating to the unit to a remote receiver, but prevents the transmitter from transmitting at other times so as to hinder detection of the tracking unit by unauthonsed monitoring of transmitted signals.

The transmitter may additionally transmit an alarm signal to a remote alarm device, and/or the tracking unit may include an integral alarm device adapted to raise an alarm in the event of detection by the sensor of the predetermined event.

Advantageously, the controller additionally sends a signal to cause the transmitter to transmit at predetermined or random or pseudorandom intervals, preferably at least 5 minutes apart.

According to a fourth aspect of the present invention, there is provided a method of article tracking wherein an article to be tracked is provided with a global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radlofrequency or other transmitter, wherein the transmitter is provided with a controller, and wherein the controller sends a signal to cause the transmitter to transmit at least location data relating to the unit to a remote receiver at random or pseudorandom intervals, preferably at least 5 minutes apart, but prevents the transmitter from transmitting at other times so as to hinder detection of the tracking unit by unauthorised monitoring of transmitted signals.

Embodiments of the present invention reduce the probability of detection by maintaining radio silence unless a specific need to transmit is recognised. This need to transmit may be triggered by external events, primarily from but not exclusively limited to motion detection by passive infra-red (PIR) detectors or motion switches such as mercury switches and vibration sensors.

The GNSS receiver may also be powered at random intervals to ensure the location has not changed.

Alternatively, the GNSS receiver may be substantially continuously powered, or powered at substantially regular intervals, preferably relatively frequently (at least once every 5 minutes, preferably at least once every minute). In this way, the GNSS tracking unit can maintain a log of its location, which may be stored in a memory of GNSS tracking unit. In some embodiments, the log can be transmitted by the transmitter in response to a predetermined control signal, which may be a remote signal issued, for example, by radio means to the GNSS tracking unit. Alternatively or in addition, the log can be downloaded from the GNSS tracking unit by a cable or other connection when required.

In this way, if the article to be tracked is stolen, the GNSS receiver will continue to monitor and log the location of the article, even when location data is not being transmitted by the transmitter. Once the log is recovered, either after transmission from the transmitter or directly from the GNSS tracking unit after the article has been retrieved following a theft, it is possible for the police or other law enforcement agencies to determine the route taken by the article during and after Its theft, together with time data. This can then be correlated with surveillance (e.g. CCTV) camera or traffic camera records from along the route taken by the article so as to obtain video or photographic evidence of the theft in progress. This evidence may include video or photographic identification of the thieves, which may be useful to assist their subsequent apprehension and prosecution.

The intervals between transmitting the at least location data may be predetermined or fixed, or may be random or pseudorandom. The intervals are preferably set to be at least 5 minutes, and may be at least 10 minutes, at least 30 minutes, at least 1 hour, at least 12 hours, at least I day, at least I week or even at least I month in duration. The longer the time of the interval, the less likely it is that a thief will be able to detect the presence of the tracking unit with a sniffer device. This is because the thief is likely to be lulled into a false sense of confidence if he does not detect any data transmissions within a reasonably lengthy time frame. On the other hand, the longer the intervals, the longer it may be before a theft is detected, but this may not be of great significance given that the location of the tracking unit will eventually be transmitted in order to allow its recovery. This is particularly true in relation to large and heavy pieces of equipment that cannot be easily or quickly moved, and/or is a fixed or semi-fixed piece of equipment such as a fixed crane or semi-portable building. Moreover, if the time period is set at days or weeks, then it is likely that the tracking unit may next transmit location data some time after it has been stolen and subsequently installed at a new location. A recipient of the stolen artide with the tracking unit is unlikely to continue monitoring or jamming, and it will be less careful than the thief who stole the article in the first place.

It is also likely that the recipient of the stolen article will be able to assist police in identifying the thief, as well as being liable to prosecution for receiving stolen goods.

Where a PIR sensor is provided, the system will maintain radio silence (sleep mode) until triggered by someone or something entering a defined region. A transmission will be made either immediately or optionally after a random or pseudorandom delay period.

The preferred destination for the transmission is a web site specifically configured for the reception of such transmissions, but transmission could also be made under short messaging service (SMS) or similar protocol containing appropriate location data. The sleep mode periods may range from seconds to weeks in duration as configured by the user. Preferably, however, the sleep mode period is set to be at least 5 minutes, and may be at least 10 minutes, at least 30 minutes, at least 1 hour, at least 12 hours, at least I day, at least I week or even at least I month. Radio silence is re-established immediately after transmission. A number of retries may be made at random intervals until a cancellation code is received by the tracking unit. The cancellation code may be a previously defined key code transmitted from a host server. Radio silence will be maintained between retry periods and any new transmissions undertaken will be a short as possible.

During sleep mode, power consumption will be kept sufficiently low that power is supplied from an internal battery in the tracking unit which will also supply power for several transmissions should its external power supply be removed. Radio emissions are advantageously sufficiently low from the standby circuits that detection of the device is difficult or impossible using conventional sniffer devices.

A further embodiment detects the presence of signal jamming. With jamming present, no radio communications can take place from the tracking unit to, for example, a radiotelephone network. Jamming can be detected by an appropriate sensor that is in communication with the controller, or may be detected by way of failure of the transmitter to establish contact with the remote receiver after a predetermined number of communication attempts. In such cases, if the system has no wired connection to the outside wotid, the system may transmit an optical or other non-radio signal to a separate jammer detect alarm. This may be triggered in such a way that no physical link can be identified between the alarm and the tracking unit thus removing the ability to trace back to the tracking unit. The tracking unit will enter radio silence mode, waking at random intervals in an attempt to transmit to the network. If the unit is unable to do so, it will return to silent mode to avoid detection.

Systems located within fixed areas with the tracking unit mounted on the asset may transmit an IR trigger signal to a remote IR receiver. This IR receiver may then actuate its own alarm system, which may include radio communication, for example GPRS radio communication. Once triggered, the tracking unit mounted on the asset will resume radio silence for random periods, repeatedly attempting communication at random intervals.

The tracking unit may be mounted on the asset in disguised form such that it appears to be a normal part of the asset and not part of a tracking system. The disguise will be appropriate for the type of asset to be protected.

Optionally, a dummy tracking unit may be provided on the asset in addition to the real (disguised or otherwise) tracking unit. The dummy tracking unit may be linked to the controller so that the real tracking unit enters sleep mode for a predetermined period after removal of or other tampering with the dummy tracking unit. This will encourage a thief to believe that the asset is no longer protected, thereby causing him to act with less care and to facilitate his apprehension later on during the course of the theft when the real tracking unit is re-activated and transmits to the remote receiver and/or issues an alarm.

The controller may communicate with the sensor or sensors by a wired connection, and/or by a wireless connection, for example an IR or other optical connection.

Throughout the descnption and daims of this specification, the words compns& and ucontain and variations of the words, for example compnsing and comprises', means ainduding but not limited to", and is not intended to (and does not) exdude other moieties, additives, components, Integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show how it may be carried Into effect, reference shall now be made by way of example to the following drawing, In which; FIGURE 1 shows a system of an embodiment of the present invention in schematic form; and FIGURE 2 is an exemplary circuit diagram of a GNSS tracking unit of an embodiment of the present invention.

DETAILED DESCRIPTION

Figure 1 shows an asset or article 2 that is to be protected. The asset 2, in the context of this specific embodiment, may be a construction vehicle or the like that is left unattended on a building site overnight. A tracking unit I with GPS/GPRS capabilities is hidden within the asset 1, and provided with wired or wireless links to a motion sensor 3 and an alarm siren or lamp 5 mounted on the asset 2, and also to a PIR detector 4 which may be mounted on the asset 2 or located elsewhere on the building site.

The tracking unit 1 is provided with a GNSS receiver, processing circuitry and a radiofrequency or other transmitter adapted to transmit at least location data relating to the unit to a remote receiver (not shown) by way of general packet radio service (GPRS) or other communications protocols. The transmitter is also provided with a controller linked to the sensors 3, 4. The controller operates to cause the transmitter to transmit when at least one of the sensors 3, 4 detects a predetermined event, such as movement of the asset I or movement within the range of the PIR detector 4 at unauthonsed times, which would indicate that a theft of the asset 2 is in progress.

The transmitter may be configured to maintain absolute radio silence at times when none of the sensors 3, 4 has been triggered, or may be adapted periodically to transmit location data only at relatively widely spaced predetermined or random or pseudorandom times. This helps to reduce the chances of the tracking unit I being detected by a sniffer device.

An optional alarm siren or lamp 5 may be provided to issue an alarm signal in the event of a detected theft.

In the event that a radio Jamming signal Is detected, or if communication with the remote receiver is not established after a predetermined number of attempts, the tracking unit I may issue an alarm signal by way of IR communications with lR receIvers 6 located on the building site. The IR receivers 6 are connected to an alarm system 7 which can raise an audible/visual alarm and/or transmit an alarm signal to a remote receiver and thence to a host server or the like.

Figure 2 shows a circuit diagram for a GNSS tracking unit I of an embodiment of the invention. The tracking unit I comprises a central processor 8 including time management and power control and management components for the system as a whole. The central processor 8 is linked to a GNSS processor 10 that provides geographical location coordinates on the basis of signals received from GNSS satellites and a GNSS-derived clock 11. There is further provided a real-time battery-backed dock 12 which serves to provide time keeping for system operation and as a clock source for a pseudorandom timer 13. The dock 12 may optionally take time data from GNSS clock 11 if available. The pseudorandom timer 13 may be located in the central processor 8 if the central processor 8 is periodically issued with a wake-up signal from dock 12. A memory unit 100 is optionally provided so as to maintain a log of location data generated by the GNSS processor.

The central processor 8 preferably also defines a pseudorandom timing algorithm based on perceived threats as detected by motion and/or intruder detection trigger system 14, which is connected by way of trigger inputs to appropriate sensors (not shown), The central processor 8 is provided with a primary power supply 15 and preferably also with a battery back-up power supply 16.

Upon detection by the sensors of a predetermined condition, the detection trigger system 14 can be configured to issue a wake-up signal to the central processor 8, which then passes current GNSS location information to a transmitter/receiver 9 for transmission to a remote host (not shown), thereby allowing the location of the tracking unit I to be monitored. Alternatively or in addition, periodic wake-up signals may be issued by the clocks 11, 12 and the pseudorandom timer 13 to cause the central processor to transmit location information by way of the transmitter/receiver 9.

In some embodiments, the GNSS components are continuously or frequently powered so as to maintain a log of location data in the memory 100, but without powering the transmitter/receIver 9 and/or without transmitting the location data.

Claims

CLAIMS: 1. A global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter adapted to transmit at least location data relating to the unit to a remote receiver, wherein the transmitter is provided with a controller linked to at least one sensor, and wherein the controller operates to cause the transmitter to transmit when the at least one sensor detects a predetermined event, but to refrain from transmitting at other times so as to hinder detection of the tracking unit by unauthorised monitoring of transmitted signals.
2. A tracking unit as claimed in claim 1, wherein the controller is additionally configured to cause the transmitter to transmit at predetermined intervals, preferably at least 5 minutes apart.
3. A tracking unit as claimed in daim 1, wherein the controller is additionally configured to cause the transmitter to transmit at random or pseudorandom intervals, preferably at least 5 minutes apart.
4. A global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter adapted to transmit at least location data relating to the unit to a remote receiver, wherein the transmitter is provided with a controller configured to cause the transmitter to transmit at pseudorandoni time intervals, preferably spaced from each other by at least 5 minutes, but to refrain from transmithng at other times so as to hinder detection of the tracking unit by unauthonsed monitoring of transmitted signals.
5. A tracking unit as claimed in any one of claims 2 to 4, wherein the intervals are least 5 minutes, at least 10 minutes, at least 30 minutes, at least 1 hour, at least 12 hours, at least I day, at least I week or at least I month apart.
6. A tracking unit as claimed in any one of claims I to 3, wherein the at least one sensor comprises a movement or motion sensor.
7. A tracking unit as claimed in claim 6, wherein the at least one sensor is a vibration sensor or tilt switch, and wherein the at least one sensor and the tracking unit are both mounted on an article to be protected.
8. A tracking unit as claimed in claim 6, wherein the at least one sensor is a passive infra-red movement sensor, and wherein the at least one sensor and the tracking unit are both mounted on an article to be protected.
9. A tracking unit as claimed in claim 6, wherein the at least one sensor is a passive infrared movement sensor, and wherein the tracking unit is mounted on an article to be protected and the infra-red movement sensor is mounted off the article to be protected.
10. A tracking unit as claimed in any preceding claim, further comprising means for detecting if radio transmissions from the transmitter are being blocked or jammed, and configured to issue an alarm signal if blocking or jamming is detected.
11. A tracking unit as claimed in claim 10, comprising an optical transmitter configured to transmit an optical alarm signal.
12. A tracking unit as claimed in claim 11, wherein the optical alarm signal is an IR signal transmitted to at least one IR receiver connected to an alarm device.
13. A tracking unit as claimed in any preceding claim, in combination with a dummy tracking unit configured to communicate with the controller and to cause the controller to activate the transmitter in the event that the dummy tracking unit is disabled or tampered with.
14. A tracking unit as claimed in any one of daims I to 3 or any one of claims 5 to 13 depending from claim 1, wherein the at least one sensor is linked to the controller by way of a hardwired connection.
15. A tracking unit as claimed in any one of claims I to 3 or any one of claims 5 to 13 depending from claim 1, wherein the at least one sensor is linked to the controller by way of a wireless connection, preferably an optical connection.
16. A tracking unit as claimed in any preceding claim, wherein the GNSS receiver is provided with a power supply that maintains operation of the GNSS receiver independently of the transmitter.
17. A tracking unit as claimed In claim 16, wherein the power supply maintains operation of the GNSS receiver substantially continuously.
18. A tracking unit as claimed in claim 16, wherein the power supply is configured to supply the GNSS receiver at substantially regular intervals.
19. A tracking unit as daimed in any preceding claim, wherein the GNSS receiver is provided with memory means and wherein the GNSS receiver is configured to store a log or record of its geographical location in the memory means.
20. A tracking unit as claimed in claim 19, wherein the transmitter is operable to transmit the log or record to the remote receiver.
21. A method of article tracking wherein an article to be tracked is provided with a global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter, wherein the transmitter is provided with a controller linked to at least one sensor, and wherein, upon detection by the sensor of a predetermined event, the controller causes the transmitter to transmit at least location data relating to the unit to a remote receiver, but prevents the transmitter from transmitting at other times so as to hinder detection of the tracking unit by unauthorised monitoring of transmitted signals.
22. A method according to claim 21, wherein the controller additionally sends a signal to cause the transmitter to transmit at predetermined intervals, preferably at least minutes apart.
23. A method according to claim 21, wherein the controller additionally sends a signal to cause the transmitter to transmit at random or pseudorandom intervals, preferably at least 5 minutes apart.
24. A method of article tracking wherein an article to be tracked Is provided with a global navigation satellite system (GNSS) tracking unit comprising a GNSS receiver, processing circuitry and a radiofrequency or other transmitter, wherein the transmitter is provided with a controller, and wherein the controller sends a signal to cause the transmitter to transmit at least location data relating to the unit to a remote receiver at random or pseudorandom intervals, preferably at least 5 minutes apart, but prevents the transmitter from transmitting at other times so as to hinder detection of the tracking unit by unauthorised monitoring of transmitted signals.
25. A method according to any one of claims 22 to 24, wherein the intervals are least 5 minutes, at least 10 minutes, at least 30 minutes, at least 1 hour, at least 12 hours, at least I day, at least I week or at least I month apart.
26. A method according to any one of claims 21 to 23, wherein the at least one sensor detects movement or motion.
27. A method according to claim 26, wherein the at least one sensor is a vibration sensor or tilt switch, and wherein the at least one sensor and the tracking unit are both mounted on an article to be protected.
28. A method according to claim 26, wherein the at least one sensor is a passive Infra-red movement sensor, and wherein the at least one sensor and the tracking unit are both mounted on an article to be protected.
29. A method according to claim 26, wherein the at least one sensor is a passive infra-red movement sensor, and wherein the tracking unit is mounted on an article to be protected and the infra-red movement sensor is mounted off the article to be protected.
30. A method according to any one of claims 21 to 29, further comprising detecting if radio transmissions from the transmitter are being blocked or jammed, and issuing an alarm signal if blocking or jamming is detected.
31. A method according to daim 30, wherein an optical alarm signal is issued by an optical transmitter.
32. A method according to claim 30, wherein the optical alarm signal is an IR signal transmitted to at least one IR receiver connected to an alarm device.
33. A method according to any one of claims 21 to 32, wherein the GNSS receiver is powered such that it can be operated independently of the transmitter.
34. A method according to claim 33, wherein the GNSS receiver is operated substantially continuously.
35. A method according to claim 33, wherein the GNSS receiver is operated at substantially regular intervals.
36. A method according to any one of claims 21 to 35, wherein the GNSS receiver is provided with memory means and wherein the GNSS receiver stores a log or record of its geographical location in the memory means.
37. A method according to claim 36, wherein the transmitter is operable to transmit the log or record to the remote receiver.
38. A security system comprising a global satellite system (GNSS) tracking unit as daimed in any one of claims I to 20, in combination with at least one sensor configured to detect movement either of the sensor or with a range of detection of the sensor.
39. A security system comprising a global satellite system (GNSS) tracking unit as daimed in any one of claims I to 20 and 38, in combination with an alarm device configured to issue an alarm if blocking or jamming of the transmitter is detected.
40. A vehicle or other structure fitted with a global satellite system (GNSS) tracking unit as claimed in any one of claims I to 20.
41. A global satellite system (GNSS) tracking unit substantially as hereinbefore described with reference to or as shown in the accompanying drawings.
42. A method of article tracking substantially as hereinbefore described with reference to or as shown in the accompanying drawings.