Information processing device, information processing method, and program

Abstract

To improve a technique for detecting camouflage of a signal to be transmitted by a positioning satellite.SOLUTION: An absolute coordinate acquisition section 130 receives a positioning signal based on a format defined as a signal to be transmitted by a navigation satellite, so as to acquire an own position coordinate indicating a position of a mobile body. A short-range wireless communication section 11 receives another position coordinate indicating a position of another mobile body from the other mobile body. A distance calculation section 131 calculates a distance between the own position coordinate and the other position coordinate. A distance acquisition section 132 acquires a distance between the mobile body and the other mobile body. A determination section 133 determines presence / absence of a possibility of camouflage in at least one of a positioning signal used for calculating the own position coordinate and a positioning signal used for calculating the other position coordinate based on a calculation distance being the distance calculated by the distance calculation section 131 and an acquisition distance being the distance acquired by the distance acquisition section 132. A notification section 134 issues a notification only when the presence of the possibility of the camouflage is determined.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an information processing device, an information processing method, and a program, and in particular to a technology for determining the position of a moving object using positioning information obtained using positioning signals from a positioning satellite, i.e., a Global Navigation Satellite System (GNSS), for determining whether the positioning signal is spoofed. [Background technology]

[0002] Spoofing of positioning signals, which involves spoofing signals transmitted by a positioning satellite, a type of artificial satellite, and mixing in false positioning information, has long been a problem, and as a countermeasure, techniques have been considered for determining whether or not the positioning signal is spoofed. Patent Document 1 discloses a spoofing determination technique that calculates the position of a vehicle based on a positioning signal received from an artificial satellite, communicates with surrounding vehicles located around the vehicle to obtain surrounding vehicle information including the positions of the surrounding vehicles, compares the positions of the surrounding vehicles included in the surrounding vehicle information with the vehicle's position, and determines that the position of the vehicle is based on a spoofed positioning signal if the difference between the two is greater than a predetermined threshold. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-015529 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology disclosed in Patent Document 1, the positions of the surrounding vehicles, which are compared with the position of the vehicle itself, are also calculated based on the positioning signal. Therefore, in the technology disclosed in Patent Document 1, it is not possible to eliminate the possibility that the positions of the surrounding vehicles are affected by spoofed positioning signals, and the reliability of the signals as a comparison target is not necessarily guaranteed. Thus, it is believed that there is room for improvement in the technology for detecting spoofed signals transmitted by navigation satellites.

[0005] The present invention has been made in consideration of these points, and aims to improve the technology for detecting spoofed signals transmitted by positioning satellites. [Means for solving the problem]

[0006] A first aspect of the present invention is an information processing device mounted on a moving body. This device includes an absolute coordinate acquisition unit that receives a positioning signal based on a format defined as a signal transmitted by a navigation satellite and acquires a self-position coordinate, which is an absolute coordinate indicating the position of the moving body, a short-distance wireless communication unit that receives from another moving body different from the moving body via short-distance wireless communication, a distance calculation unit that calculates a distance between the self-position coordinate and the other-position coordinate, a distance acquisition unit that acquires a distance between the moving body and the other moving body, a determination unit that determines whether or not there is a possibility of spoofing of at least one of the positioning signal used to calculate the self-position coordinate and the positioning signal used to calculate the other-position coordinate based on a calculated distance that is the distance calculated by the distance calculation unit and an acquired distance that is the distance acquired by the distance acquisition unit, and a notification unit that notifies when it is determined that there is a possibility of spoofing.

[0007] The distance acquisition unit may acquire the acquired distance based on a signal strength of a signal received by the short-range wireless communication unit from the other moving body.

[0008] The distance acquisition unit may acquire, as the acquired distance, a distance between the moving body and the other moving body measured by a distance measuring sensor provided in the moving body.

[0009] The determination unit may determine that at least one of the positioning signal used to calculate the self-location coordinate and the positioning signal used to calculate the other person's location coordinate may have been spoofed when the ratio of the acquired distance to the absolute value of the difference between the calculated distance and the acquired distance exceeds a predetermined threshold.

[0010] The determination unit may determine that there is a suspicion that both the positioning signal used to calculate the self-position coordinate and the positioning signal used to calculate the other person's position coordinate have been spoofed if the ratio of the acquired distance to the calculated distance is below a certain predetermined threshold.

[0011] A second aspect of the present invention is also an information processing device mounted on a moving body. This device includes an absolute coordinate acquisition unit that receives a positioning signal based on a format defined as a signal transmitted by a navigation satellite and acquires time series data of self-position coordinates, which are absolute coordinates indicating the position of the moving body, a short-distance wireless communication unit that receives time series data of other-person position coordinates, which are absolute coordinates indicating the position of the other moving body, periodically received via short-distance wireless communication from another moving body different from the moving body, an acceleration acquisition unit that acquires time series data of the acceleration of the moving body acquired by an acceleration sensor that measures the acceleration of the moving body, and a time series data of the self-position coordinates, the time series data of the other-person position coordinates, and the time series data of the moving body. the time series data of the acceleration of the moving body acquired by the acceleration acquisition unit, the time series data of the positioning signal used to calculate the self-position coordinate and the positioning signal used to calculate the other person's position coordinate received by the near-field communication unit, and the time series data of the acceleration of the moving body acquired by the acceleration acquisition unit, to the learning model, and a notification unit that notifies the determination result.

[0012] The information processing device may further include a distance calculation unit that calculates time series data of the distance between the self-location coordinates and the other person's location coordinates based on time series data of the self-location coordinates and time series data of the other person's location coordinates, and the learning model may be trained to further input time series data of distance, and the model application unit may acquire the judgment result by inputting into the learning model the time series data of the self-location coordinates acquired by the absolute coordinate acquisition unit, the time series data of the other person's location coordinates received by the short-range wireless communication unit, the time series data of distance, the time series data of distance calculated by the distance calculation unit, and the time series data of acceleration of a moving body acquired by the acceleration acquisition unit.

[0013] A third aspect of the present invention is an information processing method. In this method, a processor of an information processing device mounted on a moving body executes the steps of receiving a positioning signal based on a format defined as a signal transmitted by a navigation satellite, acquiring a self-location coordinate, which is an absolute coordinate indicating the location of the moving body, based on the positioning signal, receiving a different person's location coordinate, which is an absolute coordinate indicating the location of the different moving body, from the moving body different from the moving body via short-range wireless communication, calculating a distance between the self-location coordinate and the different person's location coordinate, acquiring a distance between the moving body and the different moving body, determining whether or not at least one of the positioning signal used to calculate the self-location coordinate and the positioning signal used to calculate the different person's location coordinate is possibly spoofed based on a calculated distance, which is the distance calculated in the step of calculating the distance, and an acquired distance, which is the distance acquired in the step of acquiring the distance, and notifying when it is determined that there is a possibility of spoofing.

[0014] A fourth aspect of the present invention is a program, which causes a computer mounted on a moving body to execute the following functions: receiving a positioning signal based on a format defined as a signal transmitted by a navigation satellite, acquiring a self-location coordinate, which is an absolute coordinate indicating the location of the moving body based on the positioning signal, receiving another-party location coordinate, which is an absolute coordinate indicating the location of another moving body different from the moving body, via short-range wireless communication, calculating a distance between the self-location coordinate and the another-party location coordinate, acquiring a distance between the moving body and the other moving body, determining whether or not at least one of the positioning signal used to calculate the self-location coordinate and the positioning signal used to calculate the another-party location coordinate is possibly spoofed based on a calculated distance, which is the distance calculated in the step of calculating the distance, and an acquired distance, which is the distance acquired in the step of acquiring the distance, and a function of notifying when it is determined that there is a possibility of spoofing.

[0015] A fifth aspect of the present invention is also a program. This program causes a computer mounted on a moving body to execute the following functions: receiving a positioning signal based on a format defined for a signal transmitted by a navigation satellite; acquiring time series data of self-location coordinates, which are absolute coordinates indicating the position of the moving body, based on the positioning signal; receiving time series data of other-party position coordinates, which are absolute coordinates indicating the position of the other moving body, which is time series data periodically received via short-range wireless communication from another moving body different from the moving body; acquiring time series data of acceleration of the moving body acquired by an acceleration sensor that measures the acceleration of the moving body; acquiring from a memory unit a learning model that has been machine-learned to output a determination result as to whether or not at least one of the positioning signal used to calculate the self-location coordinates and the positioning signal used to calculate the other-party position coordinates is spoofed when the time series data of the self-location coordinates, the time series data of the other-party position coordinates, and the time series data of the acceleration of the moving body are input; acquiring the determination result by inputting the acquired time series data of the self-location coordinates, the received time series data of the other-party position coordinates, and the acquired time series data of the acceleration of the moving body into the learning model; and notifying the determination result.

[0016] In order to provide these programs or to update parts of the programs, a computer-readable recording medium having the programs recorded thereon may be provided, or the programs may be transmitted over a communication line.

[0017] Any combination of the above components, and any transformation of the present invention into a method, device, system, computer program, data structure, recording medium, etc., are also effective as aspects of the present invention. Effect of the Invention

[0018] According to the present invention, it is possible to improve the technology for detecting spoofing of signals transmitted by positioning satellites. [Brief description of the drawings]

[0019] [Figure 1] 1 is a diagram for explaining an overview of a flow of processing executed by an information processing device according to an embodiment; [Diagram 2] FIG. 2 is a diagram illustrating a functional configuration of an information processing device according to an embodiment. [Diagram 3] FIG. 2 is a schematic diagram illustrating, in graph form, the relationship between the distance between a transmitter and a receiver and the received signal strength, which is the strength of the signal received by the receiver. [Figure 4] 10 is a diagram illustrating a change over time in the ratio of the acquired distance to the absolute value of the difference between the calculated distance and the acquired distance. FIG. [Diagram 5] 4 is a flowchart illustrating a flow of information processing executed by an information processing device according to an embodiment. [Figure 6] FIG. 13 is a diagram illustrating a functional configuration of an information processing device according to a first modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] <Outline of the embodiment> 1(a)-(b) are diagrams for explaining an outline of a flow of processes executed by an information processing device 1 according to an embodiment. The outline of the embodiment will be described below with reference to FIGS. 1(a)-(b).

[0021] The information processing device 1 is a computer to be mounted on a moving body M capable of receiving a positioning signal, which is a signal transmitted by a navigation satellite S, and acquiring position information. The information processing device 1 is mounted on the moving body M, and is configured to detect whether or not the positioning signal received by the moving body M on which it is mounted may be a tampered signal. Here, the moving body M is an air vehicle having multiple rotors (a so-called drone), a vehicle such as an automobile or motorcycle, or a water drone that automatically navigates on the water. FIG. 1(a) shows an example in which the moving body M is an air vehicle. To avoid complication, only one navigation satellite S is shown in FIG. 1(a), but in general, the moving body M receives positioning signals from multiple different navigation satellites S.

[0022] In the following description, it is assumed that the moving body M is an airborne body, but the moving body M may be a moving body other than an airborne body as long as it is a moving body capable of receiving a positioning signal, which is a signal transmitted by a navigation satellite S, and acquiring position information. Furthermore, the positioning signal includes not only a signal received directly from the navigation satellite S, but also a differential GPS (Differential Global Positioning System) signal that supplements the signal, and a signal used in RTK (Real Time Kinematic).

[0023] 1(a), the information processing device 1 is based on the premise that in addition to a first moving body M1, which is a moving body M on which the information processing device 1 is mounted, there exists a second moving body M2 that moves in the vicinity of the first moving body M1 while maintaining a substantially constant distance therefrom. Hereinafter, in this specification, when there is no particular distinction between the first moving body M1 and the second moving body M2, they will simply be referred to as moving body M.

[0024] The information processing device 1 calculates the distance between the first moving body M1 and the second moving body M2 from the position coordinates acquired based on the positioning signals received by the first moving body M1 and the second moving body M2 from the navigation satellite S. Hereinafter, in this specification, the distance calculated from the position coordinates of the first moving body M1 and the second moving body M2 is referred to as the "calculated distance L1". In the example shown in FIG. 1, the position coordinates of the first moving body M1 are (X1, Y1, Z1), and the position coordinates of the second moving body M2 are (X2, Y2, Z2). Since the calculated distance L1 is a distance calculated based on the positioning signal, if the positioning signal is spoofed, it is considered that the deviation from the true distance between the first moving body M1 and the second moving body M2 will become large. Note that the position coordinates acquired based on the positioning signal received from the navigation satellite S are generally represented by latitude, longitude, and altitude. 1 shows coordinates obtained by converting a point determined by latitude, longitude, and altitude into coordinates in a three-dimensional absolute coordinate system with a predetermined position as the origin for the convenience of calculating the calculated distance L1. Since there is a one-to-one correspondence between the latitude, longitude, and altitude and the coordinates in the three-dimensional absolute coordinate system with the predetermined position as the origin, the information processing device 1 can arbitrarily change the coordinate system to be used.

[0025] The information processing device 1 acquires the distance between the first moving body M1 and the second moving body M2 by another method for estimating the distance between the first moving body M1 and the second moving body M2 that does not depend on the positioning signal received from the navigation satellite S. Hereinafter, in this specification, the distance acquired by the information processing device 1 by another method that does not depend on the positioning signal received from the navigation satellite S is referred to as the "acquired distance L2". In the example shown in FIG. 1(a), the information processing device 1 mounted on the first moving body M1 acquires the position coordinates of the second moving body M2 from the known short-range wireless communication technology. As an example of the above-mentioned another method, the information processing device 1 estimates the acquired distance L2, which is the distance between the first moving body M1 and the second moving body M2, from the received signal strength (Received Signal Strength Indicator; RSSI) of a signal that transmits the position coordinates of the second moving body M2.

[0026] 1(a), the spoofing signal generator D is implemented by a Software Defined Radio (SDR) and outputs signals that are simulated to be transmitted by multiple navigation satellites S. Specifically, the spoofing signal generator D generates a positioning signal based on a format defined for signals transmitted by the navigation satellite S, and transmits the positioning signal while masquerading as the navigation satellite S.

[0027] FIG. 1(b) is a schematic diagram showing the time change of the acquired distance L1 (shown by a solid line) and the second distance L2 (shown by a dashed line) in a graph format, with the horizontal axis representing time and the vertical axis representing distance. Since the first moving body M1 and the second moving body M2 fly in the air, some fluctuation occurs even if the distance between them is controlled to be a constant distance (distance L0). In addition, since the acquired distance L2 is an estimated value based on RSSI, an estimation error is included in the acquired distance L2. As a result, as shown in FIG. 1(b), although the acquired distance L2 fluctuates with time, it generally remains close to the distance L0.

[0028] In contrast, the calculated distance L1 shown by the solid line has a discontinuous value over time. Specifically, in Fig. 1(b), the calculated distance L1, like the acquired distance L2, also fluctuates near the distance L0 until time T1, but the value of the calculated distance L1 increases rapidly from time T1 to time T2. This is because the position coordinates of only one of the first moving body M1 and the second moving body M2 are spoofed by receiving the spoof signal transmitted by the spoof signal generating device D from time T1 to time T2.

[0029] From time T2 to time T3, neither the first moving body M1 nor the second moving body M2 is affected by the camouflage signal transmitted by the camouflage signal generator D, so the calculated distance L1 again remains close to the distance L0. After that, from time T3 to time T4, both the first moving body M1 and the second moving body M2 are simultaneously affected by the camouflage signal transmitted by the same camouflage signal generator D. When both the first moving body M1 and the second moving body M2 calculate their position coordinates based on the same camouflage signal, the position coordinates are the same or similar. Therefore, as shown in FIG. 1(b), from time T3 to time T4, the calculated distance L1 is a very small value compared to L0.

[0030] In this way, the information processing device 1 can determine the possibility that the positioning signal received by at least one of the first moving body M1 and the second moving body M2 is spoofed by using the calculated distance L1 calculated from the position coordinates based on the positioning signal and the acquired distance L2 estimated based on the RSSI that does not depend on the positioning signal. In recent years, mobile bodies such as drones are frequently equipped with short-range wireless communication modules, and even if they are not equipped with them, the short-range wireless communication module itself is inexpensive and does not consume much power. Therefore, the information processing device 1 can realize the determination of the spoofing of the positioning signal at low cost.

[0031] <Functional configuration of information processing device 1 according to the embodiment> FIG. 2 is a diagram showing a schematic functional configuration of an information processing device 1 according to an embodiment. The information processing device 1 is mounted on a mobile object M, and includes a storage unit 10, a short-range wireless communication unit 11, a positioning signal receiving unit 12, and a control unit 13. In FIG. 2, arrows indicate main data flows, and there may be data flows not shown in FIG. 2. In FIG. 2, each functional block indicates a configuration in functional units, not a configuration in hardware (device) units. Therefore, the functional blocks shown in FIG. 2 may be implemented in a single device, or may be implemented separately in multiple devices. Data may be exchanged between functional blocks via any means, such as a data bus, a network, or a portable storage medium.

[0032] The storage unit 10 is a large-capacity storage device such as a ROM (Read Only Memory) that stores the BIOS (Basic Input Output System) of the computer that realizes the information processing device 1, a RAM (Random Access Memory) that serves as the working area of ​​the information processing device 1, an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that stores the OS (Operating System), application programs, and various information referenced when the application programs are executed.

[0033] The short-range wireless communication unit 11 is a communication interface for the information processing device 1 to communicate with an external device, and is realized by a known communication module such as a Bluetooth (registered trademark) module, a Wi-Fi (registered trademark) module, a UWB (Ultra-Wide Band) module, etc. The positioning signal receiving unit 12 is a module for the information processing device 1 to receive a positioning signal from a navigation satellite S, and is realized by, for example, a known GPS module.

[0034] The control unit 13 is a processor such as a CPU (Central Processing Unit) or GPU (Graphics Processing Unit) of the information processing device 1, and functions as an absolute coordinate acquisition unit 130, a distance calculation unit 131, a distance acquisition unit 132, a judgment unit 133, and a notification unit 134 by executing programs stored in the memory unit 10.

[0035] The absolute coordinate acquisition unit 130 receives a positioning signal based on a format defined as a signal transmitted by a navigation satellite S, and acquires self-position coordinates (position information such as latitude, longitude, and altitude) which are absolute coordinates indicating the position of the mobile body M. The short-range wireless communication unit 11 receives other-person position coordinates which are absolute coordinates indicating the position of the other mobile body M via short-range wireless communication from another mobile body M different from the mobile body M equipped with the information processing device 1.

[0036] The distance calculation unit 131 calculates a calculated distance L1 between the self-position coordinates, which are the position coordinates of the first moving body M1, and the other-position coordinates, which are the position coordinates of the second moving body M2. The distance acquisition unit 132 acquires the distance between the first moving body M1 and the second moving body M2. Specifically, the distance acquisition unit 132 acquires the acquired distance L2 based on the signal strength of the signal received by the short-range wireless communication unit 11 from the second moving body M2.

[0037] Fig. 3 is a schematic diagram showing, in a graph form, the relationship between the distance between the transmitter and the receiver and the received signal strength (RSSI), which is the strength of the signal received by the receiver. Fig. 3 is created by placing the receiver provided in the first moving body M1 and the transmitter provided in the second moving body M2 at a number of different distances in advance and measuring the received signal strength at the receiver. The information processing device 1 stores data showing the relationship between the received signal strength and distance shown in Fig. 3 in the storage unit 10 in advance. The distance acquisition unit 132 acquires an acquired distance L2 from the received signal strength of the signal received by the short-range wireless communication unit 11 by referring to the data stored in the storage unit 10.

[0038] Returning to the description of Fig. 2, the determination unit 133 determines whether or not there is a possibility of spoofing at least one of the positioning signal used to calculate the self-position coordinate and the positioning signal used to calculate the other person's position coordinate, based on the calculated distance L1, which is the distance calculated by the distance calculation unit 131, and the acquired distance L2, which is the distance acquired by the distance acquisition unit 132. Although the details of the determination process by the determination unit 133 will be described later, as outlined with reference to Fig. 1(b), the determination unit 133 can determine whether or not there is a possibility of spoofing the positioning signal by detecting a deviation between the calculated distance L1 and the acquired distance L2.

[0039] The notification unit 134 notifies the result of the determination by the determination unit 133. In particular, the notification unit 134 may notify when the determination unit 133 determines that there is a possibility of counterfeiting of the positioning signal. If the moving body M is an autonomously operating body like a drone, the notification unit 134 notifies the terminal of the person who manages the operation of the moving body M of a message indicating that there is a possibility of counterfeiting. In addition, if the moving body M is an autonomously operating body like a car, the notification unit 134 may output a sound indicating that there is a possibility of counterfeiting to an audio output unit (not shown) such as a speaker provided on the moving body M.

[0040] In this way, the information processing device 1 according to the embodiment can provide a new technique for detecting spoofing of a signal transmitted by a navigation satellite S.

[0041] Here, if the first moving body M1 is equipped with a known distance measurement sensor, the distance acquisition unit 132 may acquire the distance between the first moving body M1 and the second moving body M2 measured by the distance measurement sensor equipped in the first moving body M1 as the acquired distance L2, instead of estimating the distance using the received signal strength. Distance measurement by the distance measurement sensor is a distance acquisition method that does not depend on a positioning signal, similar to distance estimation by received signal strength, and distance measurement by the distance measurement sensor is advantageous in that it can improve the accuracy of the distance compared to distance estimation by received signal strength. The distance measurement sensor may be of any type, such as LiDAR (Light Detection And Ranging), stereo camera, radar, etc., as long as it can measure the distance to surrounding moving bodies.

[0042] Next, a process of determining whether or not there is a possibility of counterfeiting of a positioning signal by the determining unit 133 will be described.

[0043] When a value V of the ratio of the acquired distance L2 to the absolute value of the difference between the calculated distance L1 and the acquired distance L2 exceeds a predetermined threshold Th, the determination unit 133 determines that at least one of the positioning signal used to calculate the self-position coordinates, which are the position coordinates of the first moving body M1, and the positioning signal used to calculate the other person's position coordinates, which are the position coordinates of the second moving body M2, may have been spoofed. Specifically, the determination unit 133 calculates a value V shown in the following formula (1) and compares it with the threshold Th.

[0044]

number

[0045] 4 is a diagram showing a time change in the value V of the ratio of the acquired distance L2 to the absolute value of the difference between the calculated distance L1 and the acquired distance L2. In FIG. 4, since neither the first moving body M1 nor the second moving body M2 is affected by the spoofed signal until time T1, the calculated distance L1 and the acquired distance L2 are almost equal. Therefore, the value V, which is the ratio of the acquired distance L2 to the absolute value of the difference between the calculated distance L1 and the acquired distance L2, is V≈0. In FIG. 4 as well, the value V is close to 0 until time T1.

[0046] Between time T1 and time T2, either the first moving body M1 or the second moving body M2 was affected by the spoofed signal, so the calculated distance L1 was significantly larger than the acquired distance L2, with calculated distance L1 >> acquired distance L2. Therefore, the value V, which is the ratio of the acquired distance L2 to the absolute value of the difference between calculated distance L1 and acquired distance L2, is V ≈ calculated distance L1 / acquired distance L2 >> 1. In Figure 4 as well, the value of V is greater than 1 between time T1 and time T2.

[0047] Between time T3 and time T4, both the first moving body M1 and the second moving body M2 are affected by the same spoofed signal. Therefore, the position coordinates of the first moving body M1 and the second moving body M2 are the same or similar, so the calculated distance L1 is 0. At this time, the value V, which is the ratio of the acquired distance L2 to the absolute value of the difference between the calculated distance L1 and the acquired distance L2, is V ≈ |-L2| / L2 = 1. In FIG. 4 as well, the value of V is 1 between time T3 and time T4.

[0048] From the above, the determination unit 133 according to the embodiment sets the threshold Th to 0.5, and when the value V is 0.5 or more, determines that at least one of the positioning signal used to calculate the position coordinates of the first moving body M1 and the positioning signal used to calculate the position coordinates of the second moving body M2 may have been spoofed. Note that the value of the threshold Th is stored in the storage unit 10, and the user of the information processing device 1 can change the value at any time.

[0049] As described above, the value V differs between a case where either the first moving body M1 or the second moving body M2 is affected by a spoof signal and a case where both the first moving body M1 and the second moving body M2 are affected by the same spoof signal. That is, the determination unit 133 can determine, based on the magnitude of the value V, whether only either the first moving body M1 or the second moving body M2 is affected by the spoof signal, or whether both the first moving body M1 and the second moving body M2 are affected by the spoof signal.

[0050] When neither the first moving body M1 nor the second moving body M2 is affected by the spoofed signal, the calculated distance L1 and the acquired distance L2 are approximately equal. Also, as described above, when both the first moving body M1 and the second moving body M2 are affected by the same spoofed signal, the calculated distance L1 is approximately 0. Therefore, the value V2 obtained by dividing the calculated distance L1 by the acquired distance L2 can be a criterion for determining whether or not both the first moving body M1 and the second moving body M2 are likely to be affected by the same spoofed signal.

[0051] Therefore, when the value V2 of the ratio of the acquired distance L2 to the calculated distance L1 is equal to or less than a certain threshold Th2, the determination unit 133 determines that both the positioning signal used to calculate the self-location coordinates and the positioning signal used to calculate the other person's location coordinates are suspected to be spoofed. The predetermined threshold Th2 may be a value between 0 and 1, for example, 0.5. The predetermined threshold Th2 is also stored in the storage unit 10, and the user of the information processing device 1 can change its value at any time.

[0052] <Processing flow of the information processing method executed by the information processing device 1> 5 is a flowchart for explaining the flow of information processing executed by the information processing device 1 according to the embodiment. The processing in this flowchart starts, for example, when the information processing device 1 is started.

[0053] The positioning signal receiving unit 12 of the first moving body M1 receives a positioning signal based on a format defined for signals transmitted by the navigation satellite S (S2). The absolute coordinate acquiring unit 130 acquires self-position coordinates, which are absolute coordinates indicating the position of the first moving body M1 (S4).

[0054] The short-range wireless communication unit 11 receives and acquires, from the second moving body M2, which is a moving body different from the first moving body M1, other's position coordinates, which are absolute coordinates indicating the position of the second moving body M2, via short-range wireless communication (S6). The distance calculation unit 131 calculates the calculated distance L1, which is the distance between the self-position coordinates and the other's position coordinates (S8).

[0055] The distance acquisition unit 132 acquires an acquired distance L2, which is the distance between the first moving body M1 and the second moving body M2 and is acquired by a method that does not depend on the positioning signal (S10). The determination unit 133 determines whether or not there is a possibility of spoofing at least one of the positioning signal used to calculate the self-location coordinates and the positioning signal used to calculate the other person's location coordinates, based on the calculated distance L1 and the acquired distance L2 (S12).

[0056] The notification unit 134 notifies the result of the determination made by the determination unit 133 (S14). When the notification unit 134 notifies the result of the determination made by the determination unit 133, the process in this flowchart ends.

[0057] <Advantages of the Information Processing Device 1 According to the Embodiment> As described above, the information processing device 1 according to the embodiment can improve the technology for detecting spoofing of signals transmitted by positioning satellites.

[0058] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing and integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination also has the effect of the original embodiment. Such modifications will be described below.

[0059] <First Modification> In the above, a case has been described in which the information processing device 1 determines the possibility of spoofing a positioning signal by calculating the value V based on the formula (1) using the calculated distance L1 and the acquired distance L2. This can also be considered as the information processing device 1 independently performing spoofing determination at each specific time. Instead, the information processing device 1 according to the first modified example performs spoofing determination by referring to time series data of the self-location coordinates and other person's location coordinates and time series data of the acceleration of the first moving body M1 and analyzing the fluctuations thereof.

[0060] Specifically, the information processing device 1 according to the first modification executes the spoofing judgment using a machine learning model for judging the possibility of spoofing the positioning signal. More specifically, the information processing device 1 according to the first modification has a learning model that has been machine-learned to output a judgment result of whether or not at least one of the positioning signal used to calculate the self-location coordinate and the positioning signal used to calculate the other person's location coordinate is spoofed when time series data of the self-location coordinate, time series data of the other person's location coordinate, and time series data of the acceleration of the moving object are input, and executes the spoofing judgment using the machine learning model.

[0061] The information processing device 1 according to the first modification will be described below, with parts common to the information processing device 1 according to the above-described embodiment being omitted or simplified as appropriate. In the following, the information processing device 1 according to the first modification will be simply referred to as the information processing device 1, except when distinguishing it from the information processing device 1 according to the above-described embodiment.

[0062] FIG. 6 is a diagram showing a schematic functional configuration of an information processing device 1 according to a first modified example. The information processing device 1 is mounted on a first moving body M1, and includes a storage unit 10, a short-range wireless communication unit 11, a positioning signal receiving unit 12, a control unit 13, and an acceleration sensor 14. In FIG. 6, arrows indicate main data flows, and there may be data flows not shown in FIG. 6. In FIG. 6, each functional block indicates a functional unit configuration, not a hardware (device) unit configuration. Therefore, the functional blocks shown in FIG. 6 may be implemented in a single device, or may be implemented separately in multiple devices. Data may be exchanged between functional blocks via any means, such as a data bus, a network, or a portable storage medium.

[0063] The memory unit 10 is a large-capacity storage device such as an HDD or SSD that stores various information, such as a ROM that stores the BIOS of the computer that realizes the information processing device 1, a RAM that serves as the working area of ​​the information processing device 1, an OS, application programs, and machine learning models that are referenced when the application programs are executed.

[0064] The short-range wireless communication unit 11 is a communication interface for the information processing device 1 to communicate with an external device, and is realized by a known communication module such as a Bluetooth module, a Wi-Fi module, a UWB module, etc. The positioning signal receiving unit 12 is a module for the information processing device 1 to receive a positioning signal from a navigation satellite S, and is realized by, for example, a known GPS module.

[0065] The control unit 13 is a processor such as a CPU or a GPU of the information processing device 1, and executes a program stored in the storage unit 10 to function as an absolute coordinate acquisition unit 130, a distance calculation unit 131, a notification unit 134, an acceleration acquisition unit 135, and a model application unit 136. The acceleration sensor 14 measures the acceleration of the first moving body M1.

[0066] The absolute coordinate acquisition unit 130 periodically receives a positioning signal based on a format defined for signals transmitted by the navigation satellite S, and acquires time-series data of self-position coordinates, which are absolute coordinates indicating the position of the first moving body M1.

[0067] The short-range wireless communication unit 11 periodically receives time series data of other person's position coordinates, which are absolute coordinates indicating the position of the second moving body M2, from the second moving body M2, which is a moving body different from the first moving body M1, via short-range wireless communication. The acceleration acquisition unit 135 acquires time series data of the acceleration of the first moving body M1 acquired by the acceleration sensor 14.

[0068] The storage unit 10 stores a learning model that has been machine-learned to output a determination result of whether or not at least one of the positioning signal used to calculate the self-position coordinate and the positioning signal used to calculate the other person's position coordinate is spoofed when time series data of the self-position coordinate, time series data of the other person's position coordinate, and time series data of the acceleration of the moving object are input. Since this is a known method, details will be omitted, but the learning model stored in the storage unit 10 is generated by using, for example, a Long short-term memory (LSTM) network.

[0069] The model application unit 136 reads out and acquires the learning model from the storage unit 10. The model application unit 136 acquires a judgment result by inputting the time series data of the self-position coordinates acquired by the absolute coordinate acquisition unit 130, the time series data of the other person's position coordinates received by the short-range wireless communication unit 11, and the time series data of the acceleration of the first moving object M1 acquired by the acceleration acquisition unit 135 into the learning model. The notification unit 134 notifies the model application unit 136 of the judgment result acquired.

[0070] As described with reference to FIG. 1(b) and FIG. 4, the calculated distance L1 dependent on the positioning signal has a discontinuous value when at least one of the first moving body M1 and the second moving body M2 is affected by the camouflage signal generating device D. This is because the values ​​of the self-location coordinate data or the other person's location coordinate data become discontinuous when they are affected by the camouflage signal generating device D and when they are not. The machine learning model employed by the information processing device 1 according to the first modified example learns time-series data of the self-location coordinate data and the other person's location coordinate data when they are affected by the camouflage signal generating device D and when they are not affected by the camouflage signal generating device D as teacher data, and is configured to detect the influence of the camouflage signal generating device D.

[0071] In addition, the machine learning model adopted by the information processing device 1 according to the first modification also includes time series data of the acceleration of the first moving body M1 in the learning data. For example, when the first moving body M1 suddenly accelerates or decelerates, the calculated distance L1 may be observed to change discontinuously. On the other hand, when the calculated distance L1 suddenly changes even though the first moving body M1 does not suddenly accelerate or decelerate, the possibility of a sudden acceleration or deceleration of the second moving body M2 remains, but the probability that at least one of the first moving body M1 and the second moving body M2 is under the influence of a spoofed signal increases. The information processing device 1 according to the first modification can improve the accuracy of the spoofing detection technology for signals transmitted by positioning satellites by using a learning model that has learned this information by machine learning.

[0072] Here, the information processing device 1 according to the first modification may directly refer to the calculated distance L1, similarly to the information processing device 1 according to the embodiment. In this case, the distance calculation unit 131 may calculate the time series data of the calculated distance L1, which is the distance between the self-location coordinates and the other person's location coordinates, based on the time series data of the self-location coordinates and the time series data of the other person's location coordinates. In addition, the learning model may learn by further inputting the time series data of the calculated distance L1.

[0073] The model application unit 136 inputs the time series data of the self-location coordinates, the time series data of the other person's location coordinates, the time series data of the distance, the time series data of the calculated distance L1, and the time series data of the acceleration of the first moving body M1 into the learning model to obtain a determination result. By directly using the calculated distance L1, the information processing device 1 according to the first modification is expected to improve the accuracy of the spoofing detection technology for signals transmitted by positioning satellites.

[0074] <Second Modification> In the information processing device 1 according to the above embodiment, the value V relating to the calculated distance L1 and the acquired distance L2 is calculated using the formula (1). However, the method for calculating the value V is not limited to the formula (1). The information processing device 1 according to the second modification calculates the value V using the following formula (2) instead of the formula (1).

[0075]

number

[0076] Here, the determination unit 133 determines whether or not there is a possibility of counterfeiting of the positioning signal based on the condition shown in the following equation (3).

[0077]

number

[0078] In formula (3), Th3 and Th4 are spoofing judgment thresholds that are referred to when the judgment unit 133 executes spoofing judgment of the positioning signal. Now, assume that both the first moving body M1 and the second moving body M2 are affected by the spoofing signal generator D and the positioning signal is spoofed. In this case, the self-location coordinates and the other-location coordinates are the same or close to each other, so the calculated distance L1 is a small value compared to the moving distance L2. Therefore, the value V shown in formula (2) is close to 0. In contrast, when neither the first moving body M1 nor the second moving body M2 is affected by the spoofing signal generator D, the calculated distance L1 and the acquired distance L2 are close to each other. As a result, the value V shown in formula (2) is close to 1. Furthermore, assume that only one of the first moving body M1 and the second moving body M2 is affected by the spoofing signal generator D and the positioning signal is spoofed. In this case, the self-location coordinates and the other-location coordinates are significantly different from each other, and as a result, the calculated distance L1 is a large value. Therefore, the value V shown in equation (2) is also a large value far exceeding 1.

[0079] Based on the above considerations, for example, by setting Th3 = 0.5 and Th4 = 1.5, the judgment unit 133 can determine whether or not there is a possibility that either or both of the first moving body M1 and the second moving body M2 are affected by a spoofed signal. [Explanation of symbols]

[0080] 1. Information processing device 10 Storage section 11 Near Field Wireless Communication Department 12 Positioning signal receiver 13 Control section 130 Absolute coordinate acquisition unit 131 Distance calculation unit 132 Distance acquisition part 133 Judgment section 134 Notification Department 135 Acceleration acquisition section 136 Model Application Section 14 Acceleration Sensor D. Camouflage signal generator M Mobile object S Navigation Satellite

Claims

1. An information processing device mounted on a moving body, an absolute coordinate acquisition unit that receives a positioning signal based on a format defined as a signal transmitted by a navigation satellite and acquires a self-position coordinate, which is an absolute coordinate indicating a position of the moving object; a short-range wireless communication unit that receives, from another moving body different from the moving body, other position coordinates that are absolute coordinates indicating a position of the other moving body via short-range wireless communication; a distance calculation unit that calculates a distance between the self-location coordinates and the other person's location coordinates; a distance acquisition unit that acquires a distance between the moving object and the other moving object; a determination unit that determines whether or not there is a possibility of spoofing at least one of a positioning signal used to calculate the self-location coordinates and a positioning signal used to calculate the other person's location coordinates, based on a calculated distance that is the distance calculated by the distance calculation unit and an acquired distance that is the distance acquired by the distance acquisition unit; and A notification unit that notifies when it is determined that there is a possibility of counterfeiting. Information processing device.

2. the distance acquisition unit acquires the acquired distance based on a signal strength of a signal received by the short-range wireless communication unit from the other moving object. The information processing device according to claim 1 .

3. The distance acquisition unit acquires, as the acquired distance, a distance between the moving body and the other moving body measured by a distance measuring sensor provided in the moving body. The information processing device according to claim 1 .

4. When a ratio of the acquired distance to an absolute value of a difference between the calculated distance and the acquired distance exceeds a predetermined threshold, the determination unit determines that at least one of the positioning signal used to calculate the self-location coordinates and the positioning signal used to calculate the other person's location coordinates may have been spoofed. The information processing device according to claim 1 .

5. When a ratio of the acquired distance to the calculated distance is equal to or smaller than a predetermined threshold, the determination unit determines that both the positioning signal used to calculate the self-location coordinates and the positioning signal used to calculate the other person's location coordinates are suspected to be spoofed. The information processing device according to claim 1 .

6. An information processing device mounted on a moving body, an absolute coordinate acquisition unit that receives a positioning signal based on a format defined as a signal transmitted by a navigation satellite and acquires time-series data of self-position coordinates, which are absolute coordinates indicating the position of the moving object; a short-range wireless communication unit for receiving time series data periodically received via short-range wireless communication from another moving body different from the moving body, the time series data being other-body position coordinates that are absolute coordinates indicating a position of the other moving body; an acceleration acquisition unit that acquires time series data of the acceleration of the moving object acquired by an acceleration sensor that measures the acceleration of the moving object; a memory unit that stores a learning model that has been machine-learned to output a determination result of whether or not at least one of a positioning signal used to calculate the self-location coordinate and a positioning signal used to calculate the other person's location coordinate is spoofed when time series data of the self-location coordinate, time series data of the other person's location coordinate, and time series data of the acceleration of a moving object are input; a model application unit that acquires the judgment result by inputting the time series data of the self-location coordinates acquired by the absolute coordinate acquisition unit, the time series data of the other person's location coordinates received by the short-range wireless communication unit, and the time series data of the acceleration of the moving object acquired by the acceleration acquisition unit into the learning model; A notification unit that notifies the determination result. Information processing device.

7. a distance calculation unit that calculates time series data of a distance between the self-location coordinates and the other person's location coordinates based on the time series data of the self-location coordinates and the time series data of the other person's location coordinates, The learning model is trained to further input time series data of distance, the model application unit inputs the time series data of the self-position coordinates acquired by the absolute coordinate acquisition unit, the time series data of the other person's position coordinates received by the short-range wireless communication unit, the time series data of the distance, the time series data of the distance calculated by the distance calculation unit, and the time series data of the acceleration of the moving object acquired by the acceleration acquisition unit into the learning model, thereby acquiring the determination result. The information processing device according to claim 6.

8. A processor of an information processing device mounted on a moving object, receiving a positioning signal based on a format defined for signals transmitted by a navigation satellite; acquiring a self-location coordinate, which is an absolute coordinate indicating a position of the moving object, based on the positioning signal; receiving, from another moving body different from the moving body, other position coordinates which are absolute coordinates indicating a position of the other moving body via short-range wireless communication; calculating a distance between the self-location coordinates and the other person's location coordinates; acquiring a distance between the moving object and the other moving object; a step of determining whether or not there is a possibility of falsification of at least one of the positioning signal used to calculate the self-location coordinates and the positioning signal used to calculate the other person's location coordinates, based on a calculated distance, which is the distance calculated in the step of calculating the distance, and an acquired distance, which is the distance acquired in the step of acquiring the distance; and issuing a notification when it is determined that there is a possibility of forgery. Information processing methods.

9. For computers installed in moving vehicles, A function of receiving a positioning signal based on a format defined as a signal transmitted by a navigation satellite; a function of acquiring a self-location coordinate, which is an absolute coordinate indicating a position of the moving object, based on the positioning signal; A function of receiving, from another moving body different from the moving body, other position coordinates which are absolute coordinates indicating a position of the other moving body via short-range wireless communication; A function of calculating a distance between the self-location coordinates and the other person's location coordinates; A function of acquiring a distance between the moving object and the other moving object; a function of determining whether or not there is a possibility of falsification of at least one of the positioning signal used to calculate the self-location coordinates and the positioning signal used to calculate the other person's location coordinates, based on a calculated distance, which is the distance calculated in the step of calculating the distance, and an acquired distance, which is the distance acquired in the step of acquiring the distance; and A function to notify if it is determined that there is a possibility of forgery; program.

10. For computers installed in moving vehicles, A function of receiving a positioning signal based on a format defined as a signal transmitted by a navigation satellite; a function of acquiring time-series data of self-location coordinates, which are absolute coordinates indicating the position of the moving object, based on the positioning signal; a function of receiving time series data of another moving body, the time series data being periodically received via short-range wireless communication from another moving body different from the moving body, the time series data being an absolute coordinate indicating the position of the other moving body; A function of acquiring time series data of the acceleration of the moving object acquired by an acceleration sensor that measures the acceleration of the moving object; a function of acquiring from a storage unit a learning model that has been machine-learned to output a determination result as to whether or not at least one of a positioning signal used to calculate the self-location coordinate and a positioning signal used to calculate the other person's location coordinate is spoofed when time series data of the self-location coordinate, time series data of the other person's location coordinate, and time series data of the acceleration of a moving object are input; and a function of acquiring the determination result by inputting the acquired time series data of the self-location coordinates, the received time series data of the other person's location coordinates, and the acquired time series data of the acceleration of the moving object into the learning model; and notifying the user of the result of the determination. program.

Images