SENSOR NETWORK FOR DETECTING, LOCATING AND TRACKING MOBILE UNITS

Description

TECHNICAL AREA

[0001] A system for determining the position of a tracked mobile unit is described. In particular, the system enables the detection of the position of a tracked mobile unit, such as a motor vehicle, whose position determination and position reporting components are being deliberately impaired in their intended function by a source of interference located in the tracked mobile unit, using a sensor network. TECHNICAL BACKGROUND

[0002] To investigate vehicle thefts against the will of the rightful owner, some vehicles are equipped with functional units that determine the vehicle's position and transmit it via a communication network to a designated recipient (e.g., owner, manufacturer, service provider) to facilitate locating the vehicle. This transmitted information makes it possible to determine the position and movement of a stolen vehicle.

[0003] There are known methods designed to disrupt the operation of these vehicle tracking units. Such methods can aim to interfere with a tracking signal to such an extent that the stolen vehicle's position-determining unit can no longer determine its location. Alternatively, a false position signal can be transmitted to the position-determining unit by superimposing the fake signal on the actual signal. Another possibility is to disrupt the transmission signal used to transmit the vehicle's position, for example, by signal overlay.

[0004] A receiver for satellite navigation signals is often used as a positioning unit. Examples of satellite-based positioning systems are GPS and Galileo. Such receivers can generally be referred to as GNSS receivers, where GNSS stands for Global Navigation Satellite System.

[0005] EP 2 535 737 A1 describes a system and a method for determining the position of a GNSS receiver installed in a motor vehicle, whose intended function is being deliberately impaired by an interference source in the motor vehicle, using a sensor network. The sensor network comprises a multitude of sensors arranged at specific points along the road to detect a passing vehicle with the interference source and thereby determine a movement profile of the vehicle with the interference source.

[0006] DE 10 2014 218 081 A1 describes a device for reporting GNSS interference sources, comprising a receiver unit for receiving a signal in a selectable GNSS frequency band, a characterization unit for evaluating a received signal characteristic from the received signal and for determining a deviation of the received signal characteristic from an expected signal characteristic, an evaluation unit for recording data on the deviation of the received signal characteristic, and a transmission unit for at least indirectly reporting the data to an evaluation instance.

[0007] US 2013 / 0310068 A1 describes a system with multiple carrier units, each comprising a sensor unit, a position detection unit, a transceiver unit, and a processing unit. The carrier units are designed to forward a jamming signal to a central control unit.

[0008] DE 10 2014 108 418 A1 describes a method and a system for detecting a device designed to disrupt a navigation system signal. A radio signal is detected and its suitability for disrupting a navigation system signal is assessed. The area from which the radio signal is transmitted is then determined and optically detected. Finally, the optical detection is recorded and the signal characteristics are analyzed. The optical detection is then correlated with the recorded signal characteristics. SUMMARY

[0009] It can be considered a task to improve the detection of the position of mobile sources of interference, for example by increasing the coverage area of ​​a sensor network for detecting the position of mobile sources of interference.

[0010] This problem is solved with an object according to the features of independent claim 1. Further developments are set out in the dependent claims.

[0011] The system is generally suitable for tracking the movement of a jamming device. It works by inferring the position of the jamming source (or jammer) from the position of the carrier unit, whose sensor unit detects a jamming signal. Typically, a jamming device has a relatively low transmission power, so the jamming signal can only be detected over short distances (a few tens of meters up to 100 meters or a few hundred meters). Therefore, if a jamming signal is detected, this means that the jamming source is located within a radius around the sensor unit that corresponds to the jamming source's transmission range. This information is often sufficient to track and locate an illegally stolen vehicle by combining the detection information from multiple carrier units.In other words, the vehicle (mobile unit) to be tracked is located indirectly by locating the source of interference from at least one carrier unit, preferably several carrier units, thus making it possible to determine the position of the mobile unit or to track its movement. The sensor network is comprised of multiple carrier units. Each carrier unit, with its functional components, is capable of detecting an interference source (via the sensor unit), determining its own position (via the carrier unit's position determination unit), and transmitting information about the interference signal and the carrier unit's position to a central processing element, the intended recipient of the information (via the transceiver unit).

[0012] The sensor unit is specifically designed to detect electromagnetic waves within a predefined frequency range, as well as properties of the electromagnetic waves, particularly a frequency spectrum and / or power. A source of interference can be, for example, a jammer or a spoofer. Jammers prevent the detection and processing / utilization of a signal by superimposing the desired signal. For example, jammers superimpose a GNSS signal transmitted by satellites, thereby interfering with the position determination by the GNSS receiver located in the vehicle. Spoofers transmit a false GNSS signal, which is interpreted by the GNSS receiver (positioning unit) located in the vehicle being tracked as a regular GNSS signal transmitted by a satellite. This causes the GNSS receiver to determine an incorrect position.This incorrect position is then transmitted to the intended recipient of the information, but the information is worthless.

[0013] The system described here enables the sensor units of the carrier units to detect interference signals emitted by the source of interference. Interference signals are defined as any type of signal emitted by the source of interference. This could include signals that block the reception of regular GNSS signals from satellites or signals that mimic a regular GNSS signal. The detected signals are then processed to determine the presence of the source of interference in the vehicle being tracked. If an interference source is detected, information is generated indicating at least the location of the detecting carrier unit and the presence of an interference source in a vehicle being tracked within the vicinity of the detecting carrier unit.

[0014] The sensor unit can therefore detect the interference signal itself. If an interference source in the form of a spoofer is located in the vicinity of the carrier unit, the position signal of the carrier unit's position detection unit is also typically disrupted. It is thus possible for the processing unit to detect a spoofer by observing that implausible position data is being supplied by its own position detection unit. If an interference source in the form of a jammer is located in the vicinity of the carrier unit, this usually results in the carrier unit's position detection unit not supplying any position signal at all, which also enables the detection of an interference source.

[0015] The transmit / receive unit can be a cellular module. The cellular module is designed to register itself within a communication network as part of the existing communication infrastructure and to transmit data. Data transmission can be unidirectional or bidirectional.

[0016] At least one carrier unit is a mobile carrier unit. This means that the carrier unit is not statically stationary in a fixed location, but is mobile. The carrier unit can be a vehicle. In other words, the functional modules of at least one carrier unit are integrated into a vehicle. In the system, all carrier units, or at least a large proportion of them, can be mobile carrier units. It is, of course, possible that some of the carrier units are static / stationary carrier units. In that case, the system processes information from both dynamic and static carrier units to detect a jammer in a vehicle being tracked and to create a movement profile.

[0017] The movement profile created in this way can also be used to calculate road tolls. This is helpful if a jammer is used to disrupt radio communication between a vehicle and a detection device in order to prevent the vehicle from being recorded.

[0018] The use of a system with at least one mobile carrier unit allows the area covered or monitored by the sensor network to be dynamic, rather than static and constant, according to the movement pattern of the mobile carrier unit(s). The overall coverage area of ​​the sensor network is preferably designed to completely cover a desired region. However, the mobile carrier unit is able to move within this coverage area. If multiple mobile carrier units are present, they can all move within the coverage area. Preferably, the functional modules of a mobile carrier unit are arranged in or on a vehicle. When this vehicle, along with its functional modules, moves, a larger area is monitored and examined for sources of interference. It is not necessary for the vehicle with the functional modules to be in constant motion.The interference detection function can also be performed when the vehicle is parked in one location for a certain period of time. This allows the sensor network's coverage area to be dynamically adjusted to changing needs as required.

[0019] Compared to a sensor network consisting of stationary carrier units, a sensor network with at least one mobile carrier unit can effectively monitor a larger area. Alternatively, a smaller number of mobile carrier units can effectively monitor the same area as a sensor network consisting of stationary carrier units.

[0020] The processing unit is, for example, a processor or a microcontroller, which executes instructions to perform the functions described herein.

[0021] According to one embodiment, the processing unit is configured to generate a timestamp for a detection process of an interference signal and to link it to the detected interference signal before the interference signal is directed to the transmit / receive unit.

[0022] This makes it possible to create a location-time diagram for a jammer based on the location information of the detecting carrier unit and the timestamp of the jamming signal, especially when one and the same jamming signal is detected once or multiple times by several carrier units or multiple times by the same carrier unit.

[0023] The processing unit can be configured to determine a characteristic of the interference signal and link it to the detected interference signal in order to enable individualization of the interference signal.

[0024] The characteristics of an interference signal can be defined by individual and identifiable properties. Even if two or more interference sources are manufactured from nominally identical components, slight deviations occur in practice, which can be used to individualize the interference sources. These deviations are usually the result of tolerances in the mechanical, electrical, or electronic components used in the interference source. To individualize an interference signal, the spectrum within a predefined frequency range can be used. This is the frequency range in which the useful signals of the position signals from the satellites or the communication unit of the vehicle being tracked are transmitted.

[0025] Characteristic parameters for a signal can include, for example, the frequency spectrum with amplitude spectrum and / or phase spectrum. Alternatively or additionally, the spectral power density, which represents the power of a signal relative to its frequency, can be used. Other characterizing parameters can also be employed.

[0026] According to another embodiment, the central processing element is designed to compare the characteristics of several interference signals, which may originate from several carrier units, and to group the interference signals according to their characteristics in order to assign interference signals to individual jamming transmitters.

[0027] The term "interference signal" is used here to refer to a single detection event and to the signal that a sensor unit captures during a detection process. Therefore, when multiple interference signals are mentioned, this refers to the respective interference signals from several detection processes. Comparing multiple interference signals means comparing the detected signals from several detection processes. Grouping interference signals means that individual detected interference signals with the same or similar characteristics are at least provisionally linked, based on the premise that identical interference signals are highly likely to originate from the same source.

[0028] As explained above, a jamming device can be identified by the characteristics of the emitted interference signals. If a comparable interference signal is detected in several detection tests, it can be assumed with a certain probability that these interference signals originate from the same source.

[0029] To improve the accuracy of assigning or grouping individual interference signals, a plausibility check can be performed by using the timestamp of each signal. This check verifies whether the distance between two detected interference signals could have been covered within the given time interval. If a conflict arises, the corresponding interference signal is omitted during grouping.

[0030] According to another embodiment, the central processing element is designed to generate a movement profile of a single jammer from the jamming signals assigned to that single jammer.

[0031] This movement profile contains, in particular, information about the time, location, and direction of movement of the jammer. This information can originate from multiple sensor units or carrier units. This facilitates tracking the mobile unit.

[0032] According to a further embodiment, each sensor unit is designed to acquire additional environmental information in the event of a detected interference signal, wherein the additional environmental information is selected from the group consisting of: image information or electromagnetic emissions or radiation characteristics of components associated with the mobile unit to be tracked.

[0033] The image information consists, for example, of still or moving images of the surroundings of the detecting carrier unit. This image information can be used to identify the mobile unit to be located, for example, by using a human operator. In this embodiment, the image information is transmitted to the central processing element via the transmitter / receiver unit of the detecting carrier unit.

[0034] The additionally or alternatively detected electromagnetic waves relate, for example, to active systems of the mobile unit being located, such as signals emitted by driver assistance systems like distance warning systems. These signals can also typically be individualized, so that the corresponding signal can be used to assign a jamming signal to a jamming transmitter or a mobile unit being tracked.

[0035] It is also conceivable that acoustic information, such as engine noise, is captured and linked to the interference signal.

[0036] According to another embodiment, the position determination unit of the mobile unit to be tracked and the position determination unit of the majority of carrier units are designed to operate satellite-based position determination.

[0037] Positioning units are functional units that receive signals transmitted by satellites and use these signals to determine a position, or enable position determination by the processing unit. It is possible that only mobile carrier units have a satellite-based positioning unit. For stationary carrier units, the position can be specified in other ways; for example, the coordinates can be statically defined.

[0038] According to another embodiment, the sensor unit is designed to detect electromagnetic waves in a predetermined frequency range in order to detect an interference signal.

[0039] The frequency range must be selected in such a way that it includes at least the frequencies for transmitting satellite-based navigation signals and / or for transmitting data via the transceiver unit. This ensures that interference with both navigation and communication signals is detected.

[0040] According to another embodiment, the processing unit is designed to use the output signals of a reference position determination unit to detect an interference signal.

[0041] In this embodiment, the reference position determination unit is also part of the detecting carrier unit. The reference position determination unit can be the carrier unit's own position determination unit or an additional, dedicated reference position determination unit. The processing unit receives position signals or position values / coordinates from the reference position determination unit. These position signals are checked for reception quality and plausibility. If the reference position determination unit does not provide any position signals or position values / coordinates, a jammer may be the cause.However, if the reference position determination unit delivers values ​​that deviate significantly from past position values ​​or are so far removed from them that the distance could not have been covered in the corresponding time period, it may be a disturbance caused by a spoofer.

[0042] According to another embodiment, the sensor unit is designed to detect an interference signal and to determine correlation properties of the interference signal and a position determination signal in the form of a satellite signal.

[0043] To determine the presence of a spoofer, the detecting carrier unit preferably determines the correlation properties of a GNSS signal emitted by the spoofer and the GNSS signal emitted by at least one satellite. Alternatively or additionally, the traffic waypoint can also determine the received signal strengths of the GNSS signal emitted by the spoofer and the GNSS signal emitted by at least one satellite.

[0044] According to another embodiment, the transmitting / receiving unit is designed to transmit data via a mobile network or a satellite communications network.

[0045] Similar to the transmitting / receiving unit, the transmitting / receiving unit of the detecting carrier units also transmits the required data via a radio network, for example a mobile network or satellite network.

[0046] According to another embodiment, the central processing element is designed to identify information from multiple carrier units concerning the same interference signal in order to increase the accuracy of the position determination of the mobile unit to be tracked.

[0047] This embodiment is advantageous when the same jamming signal is detected simultaneously by multiple carrier units. To determine the position of a jammer with higher accuracy, triangulation mechanisms can be used. Typically, the direction to a jammer is determined from a sensor unit. This yields a direction vector. If at least two such direction vectors from separate sensor units (i.e., sensor units at different locations) are available, the position of the jammer can be determined as the intersection of the two direction vectors. This approach is also possible with more than two direction vectors.

[0048] According to another embodiment, the system is designed so that, in the event of a detected interference signal, information about the location of the interference signal is forwarded to other vehicles in order to indicate possible malfunctions of the position determination units.

[0049] The interference source disrupts the relevant signals (navigation signals, communication signals) within a certain radius, depending on the intensity of the interference signal. This interference signal can also disrupt systems other than those in the mobile unit being tracked. The embodiment described here enables a warning signal to be transmitted to vehicles located on the path of the mobile unit being tracked. For example, it is possible to estimate the path of the mobile unit being tracked on roads with a predetermined direction of travel, or generally up to the next junction with the currently traveled road. The warning signal allows vehicles on the estimated future path to be informed of the approaching interference source.This is particularly advantageous for autonomous driving applications because emerging sources of interference with navigation signals and / or communication signals can be identified early.

[0050] A jamming transmitter identification unit may be integrated into a movable unit described in connection with the system. The jamming transmitter identification unit comprises a sensor unit, a processing unit, a first interface, and a second interface. The sensor unit and the power supply unit are configured and perform the functions described in relation to the system.

[0051] The jammer identification unit has a first interface for connecting a position tracking unit. For example, a position tracking unit of the vehicle in which the jammer identification unit is installed is connected via this first interface. Alternatively or additionally, a dedicated position tracking unit can also be connected to the first interface if, for example, the vehicle equipped with the jammer identification unit does not have an integrated position tracking unit or if no required connection interface is available.

[0052] In addition, the jammer identification unit has a second interface for connecting a transceiver. This transceiver can be a module of the vehicle equipped with the jammer identification unit. Some vehicles already have such transceivers to use various mobile data services. The existing transceivers can be used to transmit the data supplied by the processing unit to the intended recipient.

[0053] Since the position determination unit and the transmit / receive unit are connected to the jammer identification unit via an interface, this offers a high degree of flexibility for retrofitting and replacement.

[0054] The first and second interfaces can be implemented physically and mechanically in a single plug-and-socket connection. However, separate connections can also be provided and used. The first and second interfaces can be wired or wireless. It is also conceivable that the sensor unit is reversibly coupled to the processing unit, allowing the sensor unit to be replaced if necessary, for example, if sensor units with different functions and performance capabilities are required.

[0055] The processing unit is functionally coupled to the sensor unit, the first interface, and the second interface. The sensor unit is designed to detect and forward to the processing unit any interference signal emitted by a jamming source that is capable of disrupting the operation of a positioning unit of a tracked mobile device. If the sensor unit detects an interference signal, the processing unit is designed to obtain the position of the jamming device identification unit via the first interface (for example, by querying the position from the positioning unit or by using a position repeatedly provided by the positioning unit) and to forward information about the emitted interference signal and / or the position of the jamming device identification unit to the second interface.

[0056] The jammer identification unit can be used to retrofit a vehicle. This vehicle can then function as a mobile carrier unit and contribute to building a dynamic sensor network for detecting and tracking jammers.

[0057] A vehicle that can be used in a system according to the invention is further described. The vehicle comprises a position determination unit, a transmitter / receiver unit, and a jammer identification unit. The position determination unit is configured to determine the vehicle's position, as described above. The transmitter / receiver unit is configured to transmit data to a remote device via a wireless connection. The vehicle also includes a jammer identification unit, as described above. The first interface is connected to the position determination unit, and the second interface is connected to the transmitter / receiver unit.

[0058] Thus, the jammer identification unit is functionally integrated into the vehicle and interacts with some of its components, at least the positioning unit and the transceiver unit. If the vehicle does not contain these components (positioning unit and transceiver unit), they can be provided separately and connected to the jammer identification unit. BRIEF DESCRIPTION OF THE FIGURES

[0059] The following describes exemplary embodiments of the invention with reference to the figures. These figures show: Fig. 1 is a schematic representation of a system according to an exemplary embodiment. Fig. 2 is a schematic representation of a jamming transmitter identification unit. Fig. 3 is a schematic representation of a vehicle. DETAILED DESCRIPTION FROM EXAMPLES OF EXECUTION

[0060] The representations in the figures are schematic and not to scale. Where the same reference numbers are used in the following figure descriptions, they refer to the same or similar elements.

[0061] Fig. 1 Figure 1 shows a schematic representation of a system 1 for determining the position of a mobile unit 20 to be tracked. The system 1 comprises a sensor network spanned by sensor units 15. The sensor units 15 are arranged in carrier units 10. Furthermore, each carrier unit 15 includes a position determination unit 11, a transmit / receive unit 12, and a processing unit 13. The system 1 also includes a central processing element 5.

[0062] In Fig. 1Three carrier units 10A, 10B, and 10C are shown. These three carrier units are functionally equivalent to one another with respect to the components mentioned. The individual components are labeled A, B, and C. The individual carrier units 10 can be stationary or mobile. In any case, the entire system 1 includes at least one mobile unit 10. For example, the functional components can be installed in a vehicle, so that the location of this mobile carrier unit can change over time.

[0063] The carrier units 10 are functionally equipped to detect a source of interference in a tracked mobile unit 20, to collect information about it, and to transmit this information to a central processing element 5. For this purpose, the transmit / receive units 12 are used, which transmit the information via a wireless connection.

[0064] A positioning unit 21 (GNSS receiver) is installed in the vehicle 20. The GNSS receiver 21 receives GNSS signals from satellites. From these GNSS signals, the GNSS receiver 21 determines its position and thus the position of the vehicle 20. The position of the vehicle 20 can optionally be processed either within the vehicle 20 or by a central unit outside the vehicle. The in Fig. 1 The central instance 5 shown receives the position data of the vehicle 20 at regular or irregular intervals, e.g. via a contactless communication interface 22.

[0065] The functionality of the GNSS receiver 21 can be impaired by a source of interference permanently or temporarily introduced into the vehicle 20. Potential sources of interference include jammers or spoofers. The jammer can prevent the detection and tracking of the GNSS signals transmitted by the satellites. As a result, the GNSS receiver 21 can no longer determine its position.

[0066] A spoofer emits a signal detectable by the GNSS receiver 21, which the GNSS receiver 21 interprets as a GNSS signal from a satellite. Since the signal emitted by the spoofer exhibits similar correlation characteristics to the GNSS signal received from a satellite, the GNSS receiver 21 may use it for position determination. However, due to this manipulated signal, the GNSS receiver cannot determine a correct position.

[0067] The sensor unit 15 in the carrier unit 10 comprises one or more sensors for detecting an interference source installed in the vehicle 20. The sensor unit 15 includes, for example, appropriate antennas to detect an electromagnetic wave.

[0068] Jammers in a motor vehicle can be detected by performing a spectrum monitoring procedure using the sensor unit 15 of the carrier unit. Alternatively or additionally, the performance of a reference GNSS receiver and its parameters with regard to acquiring and tracking a GNSS signal can be determined by the carrier unit 10 to detect a jammer.

[0069] To detect a spoofer, the carrier unit determines 10 correlation properties between a GNSS signal transmitted by the spoofer and the GNSS signal transmitted by at least one satellite. Alternatively or additionally, the received signal strengths of the GNSS signal transmitted by the spoofer and the GNSS signal transmitted by at least one satellite can be determined.

[0070] If the mobile unit 20 being tracked, carrying the source of interference, moves past the carrier units 10 with the sensor units 15, the sensor units detect the source of interference. A message about this detection result is then transmitted to the central processing unit 5. This message contains at least information about the interference signal and the position of the detecting carrier unit 10. The processing unit 13 of the detecting carrier unit 10 receives this position from the position determination unit 11 within the detecting carrier unit. Thus, the position of the source of interference is determined indirectly.

[0071] System 1 can be used, for example, to track and locate vehicles (the mobile unit 20 to be tracked) that have been stolen against the will of the authorized person. If, for example, a vehicle 20 is stolen and the signals for the position determination unit 21 and the signals emitted by the transmit / receive unit 22 are disrupted / overlaid / falsified by means of a jamming source, the carrier units 10 can detect the signals from the jamming source and thus create a movement profile of the vehicle 20 to be tracked.

[0072] System 1 allows the detection and, if necessary, tracking and easier location of objects such as stolen cars, even if these objects are hindered from locating themselves and transmitting their geospatial position by jamming devices.

[0073] In this embodiment, system 1 consists of the following components: one or more jammer detection units (sensor units 15), transmission units (transmit / receive units 12), GNSS receivers (position determination units 11), a central evaluation unit (central processing element 5), and a communication infrastructure that enables the exchange of data between the transmission units and the central evaluation unit, for example, a mobile communication network.

[0074] The sensor network consists of jamming detectors (sensor units 15), at least one of which is integrated into a vehicle, which may be in motion or at rest. Mobile communication units (transmitter / receiver units 12) are connected to these jamming detectors and are also installed in the vehicles. The jamming detectors are configured to detect, at least temporarily or continuously, the frequency spectrum of common GNSS (e.g., GPS L1 band 1565–1585 MHz) and mobile communication frequencies (e.g., GSM850, GSM900, GSM1800). Jammers can be identified, for example, by superimposing a higher power signal on the valid signal. A jammer can be detected and subsequently identified by measuring the signal strength and, if necessary, by additionally analyzing the signal characteristics.

[0075] If a stolen vehicle 20, whose GNSS-based tracking capability and possibly also its communication capability is limited or prevented by a jamming device, moves past one of the carrier units equipped with a jamming signal detector, a detection event is triggered in that carrier unit. The detection event includes, for example, the following parameters: time of detection; frequency bands of the jamming signal; level profile of the jamming signal; characteristics of the jamming signal (e.g., the temporal profile of the signal strengths as a function of frequency); fingerprint of the jamming signal; position of the detecting carrier unit at the time of detection.

[0076] This detection event, in turn, triggers the creation of a message containing the aforementioned parameters, which is then automatically sent to the evaluation unit via the communication infrastructure. If a connection cannot be established, the message is sent at a later time.

[0077] In the evaluation unit, this message is first stored in a database and is then available to users of the system for further analysis via a query system.

[0078] In the evaluation unit, incoming messages can first be automatically indexed by location and time. The various messages can also be assigned to individual stolen vehicles, with the aim of enabling tracking of the individual vehicle. For this purpose, the messages are analyzed for similarities regarding the parameters recorded during detection, in particular the signal level and time course of the individual recorded frequencies (fingerprint of the jamming signal). Based on the signal course of a jammer (fingerprint), a detection event can be linked to other detection events to individualize the jamming signal. The individualized jamming signal is then available for tracking a vehicle. Even jammers of the same type and from the same series exhibit slightly different fingerprints, e.g.as a result of the installed electronic components, and thus enable the tracking of a single jammer.

[0079] From a detected interference signal, the spectrum (power to frequency), spectrogram (frequency to time with integrated power per frequency), and periodicity can be determined. The underlying data is then evaluated to create the fingerprint (e.g., pulse strength, pulse frequency, frequency band of the signal) in order to assign the signal to a specific jammer based on its unique characteristic. Incoming messages about detection events with a high degree of commonality in parameter values ​​are linked together. These related messages can then be assigned a unique identification number, and the individual points can be sorted in a list according to the detection time. Further plausibility checks can then be performed.Among other things, the detection events can be checked using digital road network data and corresponding routing functionalities to determine whether the route between two or more detection points on the road network can be traveled by the vehicle, taking into account average speeds on the respective route at a specific time of year or day. Commercially available traffic frequency data is used for this purpose. If this assessment reveals that one or more detection points for a supposedly identical vehicle are implausible, they are removed from the list.

[0080] In a further implementation, it is conceivable to use, in addition to the existing sensors, those that allow the detected jammer to be assigned to a specific vehicle – in particular, a camera that takes a photograph of the vehicle or its license plate during detection, in order to later allow easier identification of the vehicle, e.g., by authorities or other sensor networks. This is particularly suitable for a stationary subset of the sensor network.

[0081] Finally, an automatic classification of the vehicle type (car, truck, construction equipment) could also be used to infer the vehicle's speed profile, and this information could then be used advantageously for the plausibility check described above. To simplify the recovery of stolen vehicles, it is also conceivable to spatially narrow down the future location of the vehicle by extrapolating its previous speed profile.

[0082] Fig. 2 Figure 1 shows a schematic representation of a jamming transmitter identification unit 100 comprising a sensor unit 15 and a processing unit 13 coupled to the sensor unit. The processing unit 13 is also coupled to the first interface 102 and the second interface 104. The two interfaces 102 and 104 are designed to be coupled to a position determination unit and a transmit / receive unit, respectively.

[0083] Thus, the jammer identification unit 100 fulfills the function as described with reference to Fig. 1 described. However, the position tracking unit and the transceiver unit are components that are reversibly connected to the jammer identification unit. The position tracking unit and transceiver unit can, for example, be components of a vehicle. In that case, the jammer identification unit is coupled to components of the vehicle. An interface may be provided in the vehicle to establish the corresponding connection.

[0084] Fig. 3Figure 1 shows a schematic representation of a vehicle 200 with a jamming transmitter identification unit 100. The vehicle 200 corresponds to the carrier unit 10. The jamming transmitter identification unit 100 is coupled with the position determination unit 11 and the transmit / receive unit 12, which are components of the vehicle 200, in order to perform the function described herein. REFERENCE MARK LIST

[0085] 1 System 5 Central processing element 10 Carrier unit 11 Position determination unit 12 Transmit / receive unit 13 Processing unit 15 Sensor unit 20 Mobile unit to be tracked 21 Position determination unit 22 Transmit / receive unit 100 Jammer identification unit 102 First interface 104 Second interface 200 Vehicle

Claims

1. System (1) for determining the position of a mobile unit (20) to be tracked, in which an interference source is located, the system (1) comprising: a central processing element (5); and a plurality of carrier units (10A, 10B, 10C), each carrier unit comprising a sensor unit (15A, 15B, 15C), a position determination unit (11A, 11B, 11C), a transmitting / receiving unit (12A, 12B, 12C), and a processing unit (13A, 13B, 13C), wherein the processing unit is functionally coupled to the sensor unit, the position determination unit, and the transmitting / receiving unit; wherein the sensor unit (15A, 15B, 15C) is designed to detect an interference signal emitted by the interference source, which is capable of interfering with the operation of a position determination unit (21) and / or transmitting / receiving unit (22) of the mobile unit (20) to be tracked, and to forward it to the processing unit; wherein the processing unit (13A, 13B, 13C) is designed, in the event that the sensor unit detects an interference signal, to obtain a position of the carrier unit (10A, 10B, 10C) from the position determination unit (11A, 11B, 11C) of the carrier unit and to forward information about the detected interference signal and the position of the carrier unit to the transmitting / receiving unit; wherein the transmitting / receiving unit (12A, 12B, 12C) is configured to transmit the obtained information to the central processing element (5); wherein at least one of the plurality of carrier units (10A, 10B, 10C) is a movable carrier unit; wherein each of the plurality of carrier units (10A, 10B, 10C) is configured to trigger a detection event when the mobile unit (20) to be tracked, whose positioning capability based on a global navigation satellite system is restricted or prevented by the interference source, moves past that carrier unit, characterized in that the detection event includes the following parameters: time of detection, frequency bands of the interference signal, level curve of the interference signal, characteristics of the interference signal as a time curve of the signal strength as a function of frequency, fingerprint containing a signal level and time curve of the individual recorded frequencies of the interference signal, position of the detecting carrier unit at the time of detection, and triggering the creation of a message containing the aforementioned parameters by the detection event, which is automatically sent to the central processing element (5) via a communication infrastructure, wherein the central processing element (5) is designed storing the message about detection events in a database and automatically indexing incoming messages by location and time and examining them for similarities with regard to the parameters recorded during detection in order to enable individualization of the interference signal by linking a detection event to other detection events on the basis of the fingerprint of the interference signal in order to individualize the interference signal, wherein the central processing element (5) is further configured to determine the position of the mobile unit (20) to be tracked on the basis of the individualized interference signal by inferring the position of the interference source from the position of the detecting carrier unit.

2. System (1) according to claim 1, wherein the processing unit (13A, 13B, 13C) is designed to generate a time stamp for a detection process of an interference signal and to link it to the detected interference signal before the interference signal is forwarded to the transmitting / receiving unit.

3. System (1) according to one of the preceding claims, wherein the central processing element (5) is designed to compare the characteristics of multiple interference signals with each other and to group the interference signals according to their characteristics in order to assign interference signals to individual interference transmitters.

4. System (1) according to claim 3, wherein the central processing element (5) is designed to generate a movement profile of this individual interference transmitter from the interference signals assigned to an individual interference transmitter.

5. System (1) according to one of the preceding claims, wherein the sensor unit (15A, 15B, 15C) is designed to capture additional environmental information in the event of a detected interference signal; wherein the additional environmental information is selected from the group: image information or electromagnetic emissions or radiation characteristics of components associated with the mobile unit to be tracked.

6. System (1) according to one of the preceding claims, wherein the position determination unit (21) of the mobile unit (20) to be tracked and the position determination unit (11A, 11B, 11C) of at least one of the plurality of carrier units (10A, 10B, 10C) are designed to perform satellite-based position determination.

7. System (1) according to any of the preceding claims, wherein the sensor unit (12A, 12B, 12C) is designed to detect an interference signal by detecting electromagnetic waves in a predetermined frequency range.

8. System (1) according to one of the preceding claims, wherein the processing unit is designed to use the output signals of a reference position determination unit to detect an interference signal.

9. System (1) according to one of the preceding claims, wherein the sensor unit (15A, 15B, 15C) is designed to detect a disturbance signal, to determine correlation properties of the disturbance signal and a position determination signal in the form of a satellite signal.

10. System (1) according to one of the preceding claims, wherein the transmitting / receiving unit (12A, 12B, 12C) is designed to transmit data via a mobile radio network or a satellite communication network.

11. System (1) according to one of the preceding claims, wherein the central processing element (5) is configured to identify information from a plurality of carrier units relating to the same interference signal in order to increase the accuracy of the position determination of the mobile unit to be tracked.

12. System (1) according to any of the preceding claims, wherein the system is designed such that, in the event of a detected interference signal, information about the location of the interference signal is forwarded to other vehicles in order to indicate possible interference with the position determination units.