Information processing system, information processing method, and information processing program

Abstract

This system provides an information processing system for estimating the location of spoofers that impersonate satellite signals. [Solution] The information processing system comprises: a signal acquisition unit that acquires multiple signals received at multiple locations; a determination unit that determines whether each of the multiple signals is a satellite signal or a spoof signal based on whether or not the received signal is signed; a determination unit that identifies multiple reception locations where the signal determined by the determination unit to be a spoof signal was received; an estimation unit that estimates the transmission location of the spoof signal based on the multiple reception locations identified by the determination unit; and an output unit that outputs the transmission location.

Description

Technical Field

[0001] The present invention relates to an information processing system, an information processing method, and an information processing program for estimating the position of a device that obstructs the reception of satellite signals.

Background Art

[0002] Conventionally, there is a technology for performing positioning using a positioning system such as GNSS (Global Navigation Satellite System). The positioning is performed by receiving signals from satellites. By the way, there may be a spoofing device that spoofs the signals from the satellites to disrupt the position information. In order to avoid the deviation of positioning due to the spoofing signals from such a spoofing device, Patent Document 1 discloses a navigation message authentication system that authenticates whether the signals received by an in-vehicle device performing positioning are legitimate signals.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the receiver does not have the authentication system as shown in Patent Document 1, there is a problem that it is still exposed to the threat of spoofing devices.

[0005] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an information processing system, an information processing method, and an information processing program capable of estimating the position of a device that obstructs the reception of satellite signals.

Means for Solving the Problems

[0006] An information processing system according to one embodiment of the present invention includes: a signal acquisition unit that acquires multiple signals received at multiple locations; a determination unit that determines whether each of the multiple signals is a satellite signal or a spoof signal based on whether or not the received signal is signed; a determination unit that identifies multiple reception locations where the signal determined by the determination unit to be a spoof signal was received; an estimation unit that estimates the transmission location of the spoof signal based on the multiple reception locations identified by the determination unit; and an output unit that outputs the transmission location.

[0007] An information processing method in one embodiment of the present invention involves a computer performing the following steps: a signal acquisition step of acquiring multiple signals received at multiple locations; a determination step of determining whether each of the multiple signals is a satellite signal or a spoofer signal based on whether or not the received signal is signed; a determination step of identifying multiple reception locations where the signal determined to be a spoofer signal in the determination step was received; an estimation step of estimating the source location of the spoofer signal based on the multiple reception locations identified in the determination step; and an output step of outputting the source location.

[0008] An information processing program in one embodiment of the present invention provides a computer with a signal acquisition function that acquires multiple signals received at multiple locations; a determination function that determines whether each of the multiple signals is a satellite signal or a spoofer signal based on whether or not the received signal is signed; an identification function that identifies multiple reception locations where the signal determined by the determination function to be a spoofer signal was received; an estimation function that estimates the source location of the spoofer signal based on the multiple reception locations identified by the identification function; and an output function that outputs the source location.

[0009] Furthermore, the above-mentioned information processing system may include a reception strength acquisition unit that identifies the reception strength when a spoofer signal is received at each receiving position, and the estimation unit may further estimate the originating position of the spoofer signal based on a plurality of receiving positions and the reception strength of the spoofer signal at each receiving position.

[0010] Furthermore, in the above-mentioned information processing system, the information processing system is a portable or mobile terminal and comprises a receiving unit that receives signals and a location information acquisition unit that acquires location information of the mobile terminal, and the signal acquisition unit may acquire multiple signals that have different location information and are received by the receiving unit.

[0011] An information processing system in one embodiment of the present invention includes: a signal acquisition unit that acquires signed satellite signals received at multiple locations; a identification unit that identifies the reception location where each of the multiple signals was received; a reception strength acquisition unit that acquires the reception strength when each of the multiple signals was received; an estimation unit that estimates the source location of an interfering radio wave with low reception strength based on the location where each of the multiple signals was received and the reception strength at that location; and an output unit that outputs the source location.

[0012] An information processing method in one embodiment of the present invention involves a computer performing the following steps: a signal acquisition step of acquiring signed satellite signals received at multiple locations; a identification step of identifying the reception location where each of the multiple signals was received; a reception strength acquisition step of acquiring the reception strength when each of the multiple signals was received; an estimation step of estimating the source location of an interfering radio wave whose reception strength is low, based on the location where each of the multiple signals was received and the reception strength at that location; and an output step of outputting the source location.

[0013] An information processing program in one embodiment of the present invention provides a computer with the following functions: a signal acquisition function for acquiring signed satellite signals received at multiple locations; an identification function for identifying the reception location where each of the multiple signals was received; a reception strength acquisition function for acquiring the reception strength when each of the multiple signals was received; an estimation function for estimating the source location of an interfering radio wave with low reception strength based on the reception location where each of the multiple signals was received and the reception strength at that location; and an output function for outputting the source location.

[0014] Furthermore, in the above-mentioned information processing system, the information processing system is a portable or mobile terminal and comprises a receiving unit that receives signals and a location information acquisition unit that acquires location information of the mobile terminal, and the signal acquisition unit may acquire multiple signals that have different location information and are received by the receiving unit. [Effects of the Invention]

[0015] An information processing system in one embodiment of the present invention can estimate the location of a spoofer that impersonates satellite signals, or the location of a device that generates jamming radio waves that interfere with the reception of satellite signals. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram illustrating the outline of the spoofer search process according to Embodiment 1. [Figure 2] This is a block diagram showing an example configuration of an information processing device according to Embodiment 1. [Figure 3] This is a conceptual data diagram showing an example of the configuration of received signal information according to Embodiment 1. [Figure 4] This flowchart shows an example of the operation of the information processing device according to Embodiment 1 when searching for a spoofer. [Figure 5] (a) to (c) are illustrative diagrams of the process by which the information processing device 100 estimates the position of the spoofer 200. [Figure 6] This is a schematic diagram illustrating the outline of the spoofer search process according to Embodiment 2. [Figure 7] This is a block diagram showing an example configuration of an information processing device according to Embodiment 2. [Figure 8] This flowchart shows an example of the operation of the information processing device according to Embodiment 2 when searching for a spoofer. [Figure 9] This is a schematic diagram illustrating the outline of the search for a jamming radio wave generating device according to Embodiment 3. [Figure 10]It is a block diagram showing a configuration example of an information processing apparatus according to Embodiment 3. [Figure 11] It is a flowchart showing an operation example at the time of searching for a jamming wave generation device of an information processing apparatus according to Embodiment 3.

Mode for Carrying Out the Invention

[0017] Hereinafter, an information processing apparatus which is an embodiment of the present invention will be described in detail with reference to the drawings.

[0018] <Embodiment 1> <Overview> FIG. 1 is a schematic diagram for explaining an overview related to the search for a spoofing device.

[0019] A spoofer is a device that transmits false satellite signals. By causing a receiver to receive these false satellite signals, it can calculate false location information, thereby distorting the receiver's location information. If such a spoofer exists, for example, an autonomous vehicle's location information will deviate from its actual location, potentially preventing it from recognizing that it is traveling in the correct location and thus failing to reach its destination. Therefore, the information processing device 100 (information processing system) according to this embodiment is a device that estimates the location of the spoofer 200. The information processing device 100 according to Embodiment 1 is a communication device having at least a satellite signal receiving function and a signal authentication function capable of performing authentication of an electronic signature in the received satellite signal. The information processing device 100 is a mobile device mounted on a portable or mobile device. The information processing device 100 may be, but is not limited to, a smartphone or tablet terminal, a navigation system mounted on a vehicle, a receiver dedicated to measurement, or a drone. As shown in Figure 1, the information processing device 100 is carried by the user (or mounted on a mobile device such as a vehicle) and moves (see the arrow in Figure 1). As a result, the information processing device 100 receives signals at various locations 20a to 20i. The signals received at each location may be satellite signals from satellites 10a and 10b, or signals from the spoofer 200. It is also possible to receive signals from multiple sources (satellites 10a and 10b and the spoofer 200) at the same location.

[0020] Therefore, the information processing device 100 acquires signals received at various locations 20a to 20i, identifies the signal from the spoofer 200, and determines the location of the spoofer 200 based on the identified signal from the spoofer 200 and its reception location. Satellites 10a and 10b transmit signals with, for example, an electronic signature attached to the satellite signal so that the receiver can recognize their legitimacy. Therefore, the signals received at various locations 20a to 20i can be determined to be from satellite 10 (10a, 10b) based on the presence or absence of the electronic signature. The information processing device 100 then excludes the signals from the satellites from the acquired signals. It then estimates that the remaining signals after excluding the signals from the satellites are signals from the spoofer 200.

[0021] If the signal from the spoofer 200 is received at position 20c but not at position 20e, it can be estimated that the spoofer 200 is located on the opposite side of position 20c from position 20e (to the right of position 20c in Figure 1). Similarly, if the signal from the spoofer 200 is received at position 20h but not at position 20f, it can be estimated that the spoofer 200 is located in the direction of position 20h from position 20f. In this way, the information processing device 100 can estimate the approximate location of the spoofer 200.

[0022] Furthermore, the information processing device 100 may also acquire information indicating the received signal strength at the time of reception for the signals received at each position 20a to 20i. In this case, the information processing device 100 can estimate the position of the spoofer 200 based on the received signal strength at the time of reception of the signal from the spoofer 200 that has been identified from the signals received at each position. A stronger received signal strength at the time of reception means that the position is closer to the spoofer 200, and this allows for a more accurate estimation of the position of the spoofer 200. The following provides a detailed explanation.

[0023] <Structure> Figure 2 is a block diagram showing an example configuration of the information processing device 100. The information processing device 100 is an information processing device (computer system) that acquires signals received by information processing devices located at various locations and estimates the position of the spoofer 200 based on the acquired signals. The information processing device 100 may be implemented using, for example, a notebook PC, a tablet terminal, or a smartphone, but is not limited to these. The information processing device 100 may also be a mobile device, for example, a drone or a computer system mounted on a drone.

[0024] As shown in Figure 2, the information processing device 100 includes a communication unit 110, an input unit 120, an output unit 130, a storage unit 140, and a control unit 150.

[0025] The communication unit 110 is a communication interface that has the function of communicating with external devices. The communication unit 110 is not limited to any protocol used for communication as long as it can send and receive information, and it can be wired or wireless. For example, the communication unit 110 receives signals transmitted from the satellite 10 or the spoofer 200 and transmits them to the control unit 150. The communication unit 110 may also transmit information indicating the estimated location of the spoofer 200 to an external device, for example, according to instructions from the control unit 150.

[0026] The input unit 120 is an input interface that receives input from an operator of the information processing device 100 and transmits it to the control unit 150. The input unit 120 may be implemented by, for example, a keyboard, mouse, touch panel, microphone, etc., but is not limited to these. The input unit 120 may also be an input port to which a flash memory is connected and which transmits data stored in the flash memory to the control unit 150.

[0027] The output unit 130 is an output interface that outputs information specified by the control unit 150. The output unit 130 may be implemented by, for example, a monitor or a speaker, but is not limited to these. The output unit 130 may, for example, output information indicating the estimated position of the spoofer 200 in accordance with instructions from the control unit 150.

[0028] The storage unit 140 has the function of storing various programs and data necessary for the operation of the information processing device 100. The storage unit 140 may be implemented by, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), flash memory, etc., but is not limited to these. The storage unit 140 may also be implemented by, for example, cloud storage using a storage device on a network. The storage unit 140 may store a program that identifies the signal from the spoofer 200 from among received signals received at various locations and estimates the position of the spoofer 200 based on its reception location and reception strength. The storage unit 140 may also store information about the received signals as received signal information. Details of the received signal information will be described later.

[0029] The control unit 150 is a processor that has the function of controlling each part of the information processing device 100. The control unit 150 realizes the functions of the information processing device 100 by executing the program stored in the storage unit 140.

[0030] The control unit 150 includes a signal acquisition unit 151, a determination unit 152, a specific unit 153, a received signal strength acquisition unit 154, an estimation unit 155, an output control unit 156, and a position information acquisition unit 157.

[0031] The signal acquisition unit 151 acquires signals received at various positions 20a to 20i. The signal acquisition unit 151 may acquire received signal information (received signal information) that has been acquired in advance and stored in the storage unit 140, or it may acquire received signals transmitted from the communication unit 110.

[0032] The determination unit 152 determines whether each signal acquired by the signal acquisition unit 151 is a signal transmitted from satellite 10 or a signal from spoofer 200. The determination unit 152 makes this determination based on whether or not an electronic signature is attached to each signal acquired by the signal acquisition unit 151. The determination unit 152 determines that signals with an electronic signature are signals transmitted from satellite 10, and all other signals are signals from spoofer 200 (hereinafter referred to as spoofer signals). At this time, the determination unit 152 also authenticates the electronic signature, and if the electronic signature is not legitimate, it may determine that the signal is also a signal from spoofer 200.

[0033] The identification unit 153 identifies multiple reception locations where signals determined to be spoof signals were received. That is, the identification unit 153 identifies the reception location for each of the multiple spoof signals. Each reception location for the multiple spoof signals is location information of the device that received the spoof signal, and is stored in the received signal information of the storage unit 140 in association with each signal. Therefore, the identification unit 153 obtains the reception location of the spoof signal from the received signal information stored in the storage unit 140. Note that the location information of the spoof signal may be location information obtained using satellite signals that were not received or after the spoof signal has been excluded. The identification unit 153 transmits the identified reception locations of the spoof signals to the estimation unit 155.

[0034] The received signal strength acquisition unit 154 acquires information indicating the received signal strength at the time of reception of a signal that has been determined to be a spoof signal. The received signal strength acquisition unit 154 acquires this information from the received signal information stored in the storage unit 140. The received signal strength acquisition unit 154 transmits the acquired received signal strength of the spoof signal to the estimation unit 155. The received signal strength used is the received signal strength measured by the communication unit 110 when it received the spoof signal.

[0035] The estimation unit 155 estimates the location of the spoofer signal source, i.e., the spoofer 200, based on the signal that the determination unit 152 has determined to be a spoofer signal, and the receiving location identified by the identification unit 153. The estimation unit 155 estimates the location of the spoofer 200 based on the receiving location where the spoofer signal was received and the surrounding locations where the spoofer signal could not be received. Since the spoofer 200 is thought to be located near the center of the range in which the spoofer signal can be received, the location (within a certain range) where the spoofer 200 exists can be estimated from multiple receiving locations of the spoofer signal. The estimation unit 155 further estimates the location of the spoofer 200 based on the received intensity of the spoofer signal transmitted from the received intensity acquisition unit 154. The received intensity of the spoofer signal becomes stronger the closer the location is to the spoofer 200. The estimation unit 155, for example, plots the receiving locations of the spoofer signal on a map and identifies the range of each received intensity for each received intensity at each receiving location. The estimator 155 may then estimate the location of the spoofer 200 as being at the center of the range with the highest received signal strength. Alternatively, the estimator 155 may estimate the location of the spoofer 200 as being within this range with the highest received signal strength. The estimator 155 then transmits the estimated location of the spoofer 200 to the output control unit 156.

[0036] The output control unit 156 outputs location information indicating the location of the spoofer 200 estimated by the estimation unit 155. The output control unit 156 may output image information, in which a marker indicating the location is superimposed on map information, to the output unit 130, which acts as a monitor, as location information indicating the location of the spoofer 200. Alternatively, the output control unit 156 may output, for example, an address indicating the location as audio information to the output unit 130, which acts as a speaker, as location information indicating the location of the spoofer 200. Furthermore, the output control unit 156 may output the location information indicating the location of the spoofer 200 to an external device via the communication unit 110.

[0037] The location information acquisition unit 157 acquires the location information of the information processing device 100. The location information acquisition unit 157 acquires the location information of the information processing device 100 using a so-called positioning system such as GNSS (Global Navigation Satellite System). This location information may be used when the information processing device 100 receives signals from satellite 10 and spoofer 200 and estimates the position of spoofer 200. If the location information acquisition unit 157 has not received a signal from spoofer 200, or if it has received a spoofer signal, it excludes the spoofer signal and acquires the location information of the information processing device 100 using only the satellite signal from satellite 10. The location information acquisition unit 157 transmits the acquired location information to the estimation unit 155.

[0038] The above is an example of the configuration of the information processing device 100.

[0039] <Data> Figure 3 is a conceptual data diagram showing an example of the configuration of received signal information 300 collected by the information processing device 100. The received signal information 300 is information about signals received at various positions 20a to 20i, and includes information about signals from satellite 10 and signals from spoofer 200.

[0040] As shown in Figure 3, the received signal information 300 is information that associates the management number 301, the reception location 302, the reception strength 303, the spoofing detection result 304, and the received data 305.

[0041] Management number 301 is identification information conveniently assigned by the information processing device 100 to manage and distinguish each received signal received by the information processing device 100.

[0042] The receiving location 302 is information indicating the location where the received signal, managed by the corresponding management number 301, was received. The receiving location 302 is managed as latitude and longitude information.

[0043] Received signal strength 303 is information indicating the received signal strength measured when a received signal managed by the corresponding management number 301 is received.

[0044] The spoofing detection result 304 is information indicating whether or not the received signal managed by the corresponding management number 301 is spoofed. For example, the spoofing detection result 304 is determined by whether or not an electronic signature is attached to the received signal. If an electronic signature is attached to the received signal, it is not spoofed, and if an electronic signature is not attached to the received signal, it is spoofed. However, the presence or absence of spoofing is not limited to being determined by whether or not an electronic signature is attached to the received signal, and other methods may be used. For example, it is also possible to determine that a signal is a spoofed signal if the amount of fluctuation in the satellite clock error calculated during positioning inside the receiver performing positioning exceeds a certain value. Since the clock installed on the spoofer is less stable than the clock installed on the satellite, the presence or absence of spoofing can be detected by utilizing the fact that the above-mentioned clock error is large when receiving a signal from the spoofer and performing positioning. In Figure 3, "Yes" is shown when spoofing is detected, and "No" is shown when it is not detected.

[0045] Received data 305 is data included in the received signal and is stored in the data payload.

[0046] In the example shown in Figure 3, the receiving position 302 where the received signal with management number 301 "N00293455" was received is "X1, Y1", and the received signal strength 303 is "47". In addition, the received signal with management number 301 "N00293456" has a spoofing detection result 304 of "present", so this received signal is considered to be a signal from the spoofer 200.

[0047] The information processing device 100 can estimate the position of the spoofer 200 based on the received signal information 300.

[0048] <Operation> Figure 4 is a flowchart illustrating an example of the operation of the information processing device 100, specifically an example of the processing when estimating the position of the spoofer 200.

[0049] As shown in Figure 4, the signal acquisition unit 151 of the information processing device 100 acquires the received signal transmitted from the communication unit 110 (step S401). The signal acquisition unit 151 acquires information on the received signal strength from the communication unit 110 (step S402).

[0050] The determination unit 152 determines whether the transmitted received signal is a signal from a satellite or a signal from a spoofer based on the presence or absence of an electronic signature (step S403). The determination unit 152 transmits the information of the signal identified as a spoofer signal to the location information acquisition unit 157.

[0051] The position information acquisition unit 157 identifies the reception location of the signal identified as a spoofer signal based on signals other than the signal from the spoofer. The position information acquisition unit 157 identifies the reception location of the signal identified as a spoofer based on multiple satellite signals received within a predetermined time before and after the time the spoofer signal was received (for example, within 5 minutes, but not limited to this; any time within which it can be estimated that the signal was received at approximately the same location) (step S404). Then, the control unit 150 registers the information of each received signal in the received signal information 300 of the storage unit 140 (step S405).

[0052] The estimation unit 155 acquires information on multiple spoofing signals, that is, information on signals in the received signal information 300 where the spoofing detection result 304 is "present", from the storage unit 140 (step S406).

[0053] The estimation unit 155 estimates the position of the spoofer 200 based on information regarding the reception position and reception strength of each signal from the multiple spoofers (step S407). The estimation unit 155 transmits the estimated position of the spoofer 200 to the output control unit 156.

[0054] The output control unit 156 outputs information indicating the position of the spoofer 200 transmitted from the estimation unit 155 (step S408), and terminates the process.

[0055] In the process shown in Figure 4, steps S401 to S405 and steps S406 to S408 do not need to be executed as a series of processes, but may be executed at individual timings. Furthermore, steps S406 to S408 shown in Figure 4 may be executed at the instruction of the user of the information processing device 100, or they may be triggered when a certain number of received signal information (or spoofer signal information) within a predetermined range is registered in the received signal information 300. In this way, the information processing device 100 can identify whether the received signal is from the spoofer 200 or the satellite 10 based on the presence or absence of an electronic signature in the received signal, and estimate the position of the spoofer 200 based on the reception position and reception strength of the identified signal from the spoofer 200.

[0056] <Estimated image> Figures 5(a) to 5(c) are illustrative diagrams of the process by which the information processing device 100 estimates the position of the spoofer 200.

[0057] Figure 5(a) shows a map with the locations where signals from the spoofer 200 were received plotted. The information processing device 100 identifies the range of each received signal strength based on each of these plotted locations. In Figure 5(a), each circle represents a receiving location, and the numbers inside the circles represent information indicating the received signal strength. Here, the received signal strength is shown as a number from 0 to 5 indicating relative strength, but this may also represent the actual numerical value of the received signal strength. The range of relative signal strength may be arbitrary, but as an example, it may be defined as follows: 1 is 20 dB or less, 2 is 20 to 40 dB, 3 is 40 to 60 dB, 4 is 60 dB to 80 dB, and 5 is 80 dB or more.

[0058] Figure 5(b) shows an example of defining a range by connecting the outermost receiving locations with the same reception strength. In this case, it is possible to simply connect adjacent receiving locations, or to draw a smooth line passing through them using the least squares method or similar. Furthermore, this method of defining the range is not limited to this; the range may also be statistically determined from receiving locations with the same reception strength.

[0059] Figure 5(c) shows an example of the position of the spoofer 200 output by the output control unit 156. The output control unit 156 may output the shaded area 531 in Figure 5(c), which is the range with the highest received intensity of the spoofer signal, as the position of the spoofer 200, or it may output the center position 532 of the area 531 as the position of the spoofer 200.

[0060] <Embodiment 2> In Embodiment 1 described above, an example was shown in which the information processing device 100 moves and estimates the position of the spoofer 200 based on the spoofer signals received at various locations. However, depending on the range in which the information processing device 100 can move, there is a possibility that the number of spoofer signals may be insufficient, making it impossible to estimate the position of the spoofer 200. Therefore, in Embodiment 2, an information processing device 900 that estimates the position of the spoofer 200 based on a sufficient number of spoofer signals will be described.

[0061] The information processing device 600 estimates the position of the spoofer 200 based on the received signals received at various locations 20a to 20l. The receivers that receive signals at various locations 20a to 20l can be any device capable of receiving signals including satellite signals and communicating with them, such as a base station, a mobile terminal such as a smartphone, or a navigation system mounted on a vehicle. The receivers that receive signals at various locations 20a to 20l can be the same receiver or different receivers. The information processing device 600 may also be a device that receives signals including satellite signals. The information processing device 600 estimates the position of the spoofer 200 based on the received signals received by other receivers at various locations 20a to 20l. The concept of the information processing device 600 estimating the position of the spoofer 200 is the same as in Embodiment 1, and it identifies whether a received signal is a spoofer signal based on whether or not it has an electronic signature, and estimates the position of the spoofer 200 based on the reception location of the identified spoofer signal.

[0062] In other words, if a signal from the spoofer 200 is received at position 20e but not at position 20b, it can be estimated that the spoofer 200 is located on the opposite side of position 20e from position 20b. Also, if a signal from the spoofer 200 is received at position 20i but not at position 20l, it can be estimated that the spoofer 200 is located in the direction of position 20i from position 20l. In this way, the information processing device 100 can estimate the approximate location of the spoofer 200.

[0063] Furthermore, the information processing device 100 may also acquire information indicating the received signal strength at the time of reception for the signals received at each position 20a to 20l. In this case, the information processing device 100 can estimate the position of the spoofer 200 based on the received signal strength at the time of reception of the signal from the spoofer 200 that has been identified from the signals received at each position. A stronger received signal strength at the time of reception means that the position is closer to the spoofer 200, and this allows for a more accurate estimation of the position of the spoofer 200. This will be explained in detail below.

[0064] <Structure> Figure 7 is a block diagram showing an example configuration of the information processing device 600. The information processing device 600 is an information processing device (computer system) that acquires signals received by information processing devices located at various locations and estimates the position of the spoofer 200 based on the acquired signals. The information processing device 600 may be implemented using, for example, a server device, a PC, a tablet terminal, a smartphone, etc., but is not limited to these. The information processing device 600 may also be a mobile device, for example, a drone or a computer system mounted on a drone.

[0065] As shown in Figure 7, the information processing device 600 includes a communication unit 610, an input unit 620, an output unit 630, a storage unit 640, and a control unit 650.

[0066] The communication unit 610 is a communication interface that has the function of communicating with external devices. The communication unit 610 is not limited to any protocol used for communication as long as it can send and receive information, and it can be wired or wireless. For example, the communication unit 610 may receive signals (or signal information including the reception location, reception strength, and presence or absence of an electronic signature) received by information processing devices located at various positions 20a to 20l, and transmit this information to the control unit 650. Alternatively, the communication unit 610 may transmit information indicating the location of the spoofer 200 to an external device, for example, according to instructions from the control unit 650.

[0067] The input unit 620 is an input interface that receives input from an operator of the information processing device 600 and transmits it to the control unit 650. The input unit 620 may be implemented by, for example, a keyboard, mouse, touch panel, microphone, etc., but is not limited to these. The input unit 620 may also be an input port to which a flash memory is connected and which transmits data stored in the flash memory to the control unit 650. For example, the input unit 620 may transmit information from the flash memory to the control unit 650, including the received signal data, the signal reception location, and the received signal strength stored in the flash memory.

[0068] The output unit 630 is an output interface that outputs information specified by the control unit 650. The output unit 630 may be implemented by, for example, a monitor or a speaker, but is not limited to these. The output unit 630 may, for example, output information indicating the estimated position of the spoofer 200 in accordance with instructions from the control unit 650.

[0069] The storage unit 640 has the function of storing various programs and data necessary for the operation of the information processing device 600. The storage unit 640 may be implemented by, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), flash memory, etc., but is not limited to these. The storage unit 640 may also be implemented by, for example, cloud storage using a storage device on a network. The storage unit 640 may store a program that identifies the signal from the spoofer 200 from among the received signals received at various locations, and estimates the location of the spoofer 200 based on its reception location and reception strength. The storage unit 640 also stores the received signal information 300 shown in Figure 3, which was described in Embodiment 1. In this case, in the received signal information 300, identification information that can identify the information processing device that received the signal may be associated with the information of each received signal.

[0070] The control unit 650 is a processor that has the function of controlling each part of the information processing device 600. The control unit 650 realizes the functions of the information processing device 600 by executing the program stored in the storage unit 640.

[0071] The control unit 650 includes a signal acquisition unit 651, a determination unit 652, a specification unit 653, a received signal strength acquisition unit 654, an estimation unit 655, and an output control unit 656. The control unit 650 may also include a position information acquisition unit 657.

[0072] The signal acquisition unit 651 acquires signals received at various positions 20a to 20l. The signal acquisition unit 651 may acquire signals that have been acquired in advance and stored in the storage unit 640. Alternatively, when the signal acquisition unit 651 performs the process of identifying the position of the spoofer 200, it may acquire signals from various information processing devices, or it may acquire signals from a cloud server or the like that collects and stores those signals.

[0073] The determination unit 652 determines whether each signal acquired by the signal acquisition unit 651 is a signal transmitted from satellite 10 or a signal from spoofer 200. The determination unit 652 determines whether each signal acquired by the signal acquisition unit 651 has an electronic signature attached to it. The determination unit 652 determines that signals with an electronic signature attached are signals transmitted from satellite 10, and that all other signals are signals from spoofer 200 (hereinafter referred to as spoofer signals).

[0074] The identification unit 653 identifies multiple reception locations where signals determined to be spoof signals were received. That is, the identification unit 653 identifies the reception location for each of the multiple spoof signals. Each reception location for the multiple spoof signals is the location information of the device that received the spoof signal, and is stored in the received signal information of the storage unit 640 in association with each signal. Therefore, the identification unit 653 obtains the reception location of the spoof signal from the received signal information stored in the storage unit 640. Note that the location information of the information processing device that received the spoof signal may be location information obtained using satellite signals after the device has not received the spoof signal or after the spoof signal has been excluded, or, if the information processing device is a stationary station that does not move, it may be location information that has been measured and stored in advance at the station. Furthermore, if the device that received the spoof signal is the device itself, the location information of the device itself becomes the reception location of the spoof signal, and this location information is obtained by the location information acquisition unit 657. The identification unit 653 transmits the identified spoofer signal reception location to the estimation unit 655.

[0075] The received signal strength acquisition unit 654 acquires information indicating the received signal strength at the time of reception of a signal that has been determined to be a spoof signal. The received signal strength acquisition unit 654 acquires this information from the received signal information stored in the storage unit 640. The received signal strength acquisition unit 654 transmits the acquired received signal strength of the spoof signal to the estimation unit 655. If the information processing device 600 itself has received the spoof signal, the received signal strength measured by the communication unit 610 when it received the signal will be used.

[0076] The estimation unit 655 estimates the location of the spoofer signal source, i.e., the spoofer 200, based on the signal that the determination unit 652 has determined to be a spoofer signal, and based on the receiving location identified by the identification unit 653. The estimation unit 655 estimates the location of the spoofer 200 based on the receiving location where the spoofer signal was received and the surrounding locations where the spoofer signal could not be received. Since the spoofer 200 is thought to be located near the center of the range in which the spoofer signal can be received, the location (within a certain range) where the spoofer 200 exists can be estimated from multiple receiving locations of the spoofer signal. The estimation unit 655 further estimates the location of the spoofer 200 based on the received intensity of the spoofer signal transmitted from the received intensity acquisition unit 654. The received intensity of the spoofer signal becomes stronger the closer the location is to the spoofer 200. The estimation unit 655, for example, plots the receiving locations of the spoofer signal on a map and identifies the range of each received intensity for each received intensity at each receiving location. The estimator 655 may then estimate the location of the spoofer 200 as being at the center of the range with the highest received signal strength. Alternatively, the estimator 655 may estimate the location of the spoofer 200 as being within this range with the highest received signal strength. The estimator 655 then transmits the estimated location of the spoofer 200 to the output control unit 656.

[0077] The output control unit 656 outputs location information indicating the location of the spoofer 200 estimated by the estimation unit 655. The output control unit 656 may output image information, in which a marker indicating the location is superimposed on map information, as location information indicating the location of the spoofer 200 to the output unit 630, which acts as a monitor. Alternatively, the output control unit 656 may output, for example, an address indicating the location as audio information to the output unit 630, which acts as a speaker. Furthermore, the output control unit 656 may output the location information indicating the location of the spoofer 200 to an external device via the communication unit 610.

[0078] The position information acquisition unit 657 acquires the position information of the information processing device 600. The position information acquisition unit 657 acquires the position information of the information processing device 600 using a so-called positioning system such as GNSS (Global Navigation Satellite System). This position information is used when the information processing device 600 receives signals from satellite 10 and spoofer 200 and estimates the position of spoofer 200. The position information acquisition unit 657 acquires the position information of the information processing device 600 using only satellite signals from satellite 10, either when it has not received a signal from spoofer 200 or when it has excluded the spoofer signal. The position information acquisition unit 657 transmits the acquired position information to the estimation unit 655.

[0079] The above is an example of the configuration of the information processing device 600. <Operation> Figure 8 is a flowchart illustrating an example of the operation of the information processing device 600, specifically an example of the processing when estimating the position of the spoofer 200.

[0080] As shown in Figure 8, the signal acquisition unit 651 of the information processing device 600 acquires information on multiple received signals from the received signal information 300 (step S801). The signal acquisition unit 651 acquires information on received signals within a predetermined range based on the reception location of the received signals. The signal acquisition unit 651 transmits the acquired information on received signals to the determination unit 652.

[0081] The determination unit 652 determines whether each transmitted received signal is a signal from the satellite or a signal from a spoofer based on the presence or absence of a spoofing detection result (step S802). This determination may be made, for example, by checking whether "yes" is associated with the spoofing detection result 304 in the received signal information 300. The determination unit 652 transmits the information of the signal identified as a spoofer signal to the identification unit 653 and the received signal strength acquisition unit 654.

[0082] The identification unit 653 identifies the location where it received the signal determined to be a spoof signal from the determination unit 652 (step S803). The identification unit 653 transmits the information of the identified location to the estimation unit 655.

[0083] The received signal strength acquisition unit 654 acquires information on the received signal strength when it receives a signal that has been determined to be a spoof signal by the determination unit 652 (step S804). The received signal strength acquisition unit 654 transmits the acquired signal strength information to the estimation unit 655.

[0084] The estimation unit 655 estimates the position of the spoofer 200 based on information from the receiving position where each of the multiple spoofer signals identified by the identification unit 653 was received, and the received signal strength at the time of reception transmitted from the received signal strength acquisition unit 654 (step S805). The estimation unit 655 transmits the estimated position of the spoofer 200 to the output control unit 656.

[0085] The output control unit 656 outputs information indicating the position of the spoofer 200 transmitted from the estimation unit 655 (step S806), and terminates the process.

[0086] The process shown in Figure 8 may be executed at the instruction of the user of the information processing device 600, or it may be triggered when a certain number of received signal information entries within a predetermined range are registered in the received signal information 300. In this way, the information processing device 600 can identify whether a received signal is from the spoofer 200 or the satellite 10 based on the presence or absence of an electronic signature in the received signal, and estimate the position of the spoofer 200 based on the reception position and reception strength of the identified signal from the spoofer 200.

[0087] <Embodiment 3> In Embodiments 1 and 2 described above, the position of the spoofer 200 was estimated. However, methods other than spoofing can be considered to prevent the receiver from obtaining accurate positional information. For example, one could install a device that emits jamming radio waves so that the receiver cannot receive satellite signals in the first place. Therefore, Embodiment 3 describes an information processing device 900 that estimates the position of the jamming radio wave generating device.

[0088] The system configuration according to Embodiment 3 is almost the same as that of Embodiment 2, as shown in Figure 9, with the only difference being that the jamming device 700 is located near the location of the spoofer 200. Generally, when spoofing is performed, the jamming device 700 (jammer) is used beforehand to jam the satellite, that is, to forcibly disable the satellite tracking of the positioning receiver, and then make it follow the signal emitted by the spoofer 200. The information processing device 900 according to Embodiment 3 estimates the location of such a jamming device 700. This will be explained in detail below. In this Embodiment 3 as well, the information processing device 900 may be a portable or mobile device, and a single information processing device 900 may receive signals at various locations and identify the location of the jamming device 700 based on the strength of the signals.

[0089] <Structure> Figure 10 is a block diagram showing an example configuration of the information processing device 900, and its configuration is the same as that of the information processing device 100 shown in Embodiment 1 and the information processing device 600 shown in Embodiment 2. The difference lies in the configuration of the control unit; the other configurations are the same, so here we will explain the configuration of the control unit 950, and the other configurations will be omitted as they are the same as the configurations of the same name in Embodiment 1.

[0090] As shown in Figure 10, the control unit 950 includes a signal acquisition unit 951, a identification unit 952, a received signal strength acquisition unit 953, an estimation unit 954, and an output control unit 955, and may also include a position information acquisition unit 956.

[0091] The signal acquisition unit 951 acquires signals received at various positions 20a to 20l. The signal acquisition unit 951 may acquire signals that have been acquired in advance and stored in the storage unit 940. Alternatively, when the signal acquisition unit 951 performs the process of identifying the location of the jamming radio wave generator 700, it may acquire signals from various information processing devices, or it may acquire signals from a cloud server or the like that collects and stores those signals.

[0092] The identification unit 952 identifies multiple reception locations where signals acquired by the signal acquisition unit 951 were received. That is, the identification unit 952 identifies the reception location for each of the multiple signals. Each reception location for the multiple signals is location information of the device that received the signal, and is stored in the received signal information of the storage unit 940 in association with each signal. Therefore, the identification unit 952 obtains the reception location of the signal acquired by the signal acquisition unit 951 from the received signal information 300 stored in the storage unit 940. The identification unit 952 transmits the identified reception locations of the signals to the estimation unit 954.

[0093] The received signal strength acquisition unit 953 acquires information indicating the received signal strength at the time the signal acquired by the signal acquisition unit 951 is received. The received signal strength acquisition unit 953 acquires this information from the received signal information stored in the storage unit 940. The received signal strength acquisition unit 953 transmits the acquired signal received signal strength to the estimation unit 954. If the information processing device 900 itself is receiving the signal, the received signal strength measured when the communication unit 910 received the signal will be used.

[0094] The estimation unit 954 estimates the location of the source of the interfering radio waves, i.e., the location of the interfering radio wave generator 700, based on the receiving location identified by the identification unit 952 and the received intensity acquired by the received intensity acquisition unit 953. The received intensity of the signal weakens as the location approaches the interfering radio wave generator 700. The estimation unit 954 may, for example, plot the receiving locations of the signal on a map and estimate the receiving range for each received intensity based on the received intensity at each receiving location. It may then estimate the location of the interfering radio wave generator 700 to be at the center of the range with the weakest received intensity. The estimation unit 954 may also estimate this range with the weakest received intensity as the location of the generator 700. The estimation unit 954 transmits the estimated location of the generator 700 to the output control unit 955.

[0095] The output control unit 955 outputs location information indicating the location of the jamming device 700 estimated by the estimation unit 954. The output control unit 955 may output image information, in which a marker indicating the location is superimposed on map information, as location information indicating the location of the generator 700 to the output unit 930, which acts as a monitor. Alternatively, the output control unit 955 may output, for example, an address indicating the location as audio information to the output unit 930, which acts as a speaker. Furthermore, the output control unit 955 may output the location information indicating the location of the generator 700 to an external device via the communication unit 910.

[0096] The location information acquisition unit 956 acquires the location information of the information processing device 900. The location information acquisition unit 956 acquires the location information of the information processing device 900 using a so-called positioning system such as GNSS (Global Navigation Satellite System). This location information is used when the information processing device 900 receives a signal and estimates the location of the generator 700. The location information acquisition unit 956 transmits the acquired location information to the estimation unit 954.

[0097] <Operation> Figure 11 is a flowchart showing the process by which the information processing device 900 estimates the location of the jamming radio wave generating device 700.

[0098] As shown in Figure 11, the signal acquisition unit 951 of the information processing device 900 acquires information on received signals from multiple locations, that is, received signals received at various positions 20a to 20l (step S1101).

[0099] The identification unit 952 identifies location information indicating the location where each signal acquired by the signal acquisition unit 951 was received (step S1102). The identification unit 952 transmits the identified location information to the estimation unit 954.

[0100] The reception strength acquisition unit 953 acquires information indicating the reception strength at the time each signal acquired by the signal acquisition unit 951 was received (step S1103). The reception strength acquisition unit 953 transmits the acquired information indicating the reception strength to the estimation unit 954.

[0101] The estimation unit 954 estimates the location of the interference signal based on the reception location and reception intensity of each transmitted signal (step S1104). That is, the estimation unit 954 estimates the location where the reception intensity is relatively weak as the location of the interference signal generator 700. The estimation unit 954 transmits the estimated location to the output control unit 955.

[0102] The output control unit 955 outputs information indicating the estimated location of the jamming radio wave generator 700 transmitted from the estimation unit 954 (step S1105), and terminates the process.

[0103] In this way, the information processing device 900 can estimate the location of the jamming radio wave generating device 700.

[0104] <Summary> According to the information processing devices 100 and 600 of Embodiments 1 and 2, the signal from satellite 10 and the signal from spoofer 200 can be distinguished based on the presence or absence of an electronic signature, and the location of spoofer 200 can be estimated based on the reception location and reception strength of the signal from spoofer 200, thus assisting in the search for spoofer 200. Furthermore, according to the information processing device 900 of Embodiment 3, the location of the jamming radio wave generator 700 can be estimated based on the reception location and reception strength of the signal by utilizing the fact that the received signal is weakened by jamming radio waves, i.e., the reception strength decreases, thus assisting in the search for generator 700. Therefore, if spoofer 200 located at the location estimated by information processing device 100 and jamming radio wave generator 700 located at the location estimated by information processing device 900 are found and removed, the harmful effects of positioning using satellite signals from satellite 10 in the surrounding area can be eliminated.

[0105] <Supplement> The information processing devices 100 and 900 (information processing systems) according to the above embodiments are not limited to the embodiments shown above. Various modifications will be described below.

[0106] (1) In the above embodiment, the information processing devices 100 and 600 may also have the function of the information processing device 900, namely the function of estimating the location of the jamming radio wave generator 700.

[0107] (2) When the functional units of the information processing devices 100, 600, and 900 are implemented by software, the information processing device 100 includes a CPU that executes instructions for a program which is the software that implements each function, a ROM (Read Only Memory) or storage device (collectively referred to as a "recording medium") on which the program and various information are recorded in a way that can be read by a computer (or CPU), and a RAM (Random Access Memory) for which the program is loaded. The object of the present invention is achieved when the computer (or CPU) reads the program from the recording medium and executes it. That is, the information processing device 100 according to the present invention functions as the above-mentioned components when the CPU executes a program loaded on the RAM. As the recording medium, a "tangible medium that is not temporary," such as semiconductor memory or a programmable logic circuit, can be used. The program may also be supplied to the computer via any transmission medium (such as a communication network or broadcast wave) that can transmit the program. The present invention can also be realized in the form of an information signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0108] The above program can be implemented using, for example, scripting languages ​​such as ActionScript and JavaScript®, object-oriented programming languages ​​such as Objective-C, Java®, and Python®, and markup languages ​​such as HTML5.

[0109] Furthermore, each functional unit of the information processing devices 100, 600, and 900 may be implemented by logic circuits (hardware) formed on an integrated circuit (IC chip), and in that case, each functional unit may be implemented as a separate circuit, or multiple functional units may be implemented by a single circuit.

[0110] While the present invention has been described based on various drawings and embodiments, it should be noted that those skilled in the art will find it easy to make various modifications and alterations based on this disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of the present invention. For example, the functions included in each means, step, etc., can be rearranged in a logically consistent manner, and multiple means or steps, etc., can be combined into one or divided. Furthermore, the configurations shown in the above embodiments may be combined as appropriate. [Explanation of symbols]

[0111] 10,10a,10b satellite 100, 600, 900 Information Processing Devices 110, 610, 910 Communications Department 120, 620, 920 Input Section 130, 630, 930 Output section 140, 640, 940 storage section 150, 650, 950 Control Unit 151, 651, 951 Signal acquisition unit 152, 652 Judgment section 153, 653, 952 Specific part 154, 654, 953 Received signal strength acquisition unit 155, 655, 954 Estimation part 156, 955 Output control unit 157, 657, 956 Location information acquisition section 200 Spoofer 700 Generator

Claims

1. A signal acquisition unit that acquires multiple signals received at multiple locations, A determination unit that determines whether each of the aforementioned plurality of signals is a satellite signal or a spoofer signal based on whether or not the received signal is signed, The determination unit identifies multiple receiving locations where a signal that the determination unit has determined to be a spoof signal was received, An estimation unit estimates the transmission location of the spoofer signal based on a plurality of receiving locations identified by the identification unit, An output unit that outputs the aforementioned transmission position, An information processing system equipped with the following features.

2. The system includes a reception strength acquisition unit that identifies the reception strength when the spoofer signal is received at each of the aforementioned reception positions, The estimation unit further estimates the source location of the spoofer signal based on the plurality of receiving locations and the received intensity of the spoofer signal at each receiving location. The information processing system according to feature 1.

3. The aforementioned information processing system is a portable or mobile terminal. A receiving unit that receives signals, The system includes a location information acquisition unit that acquires location information of the aforementioned mobile terminal, The signal acquisition unit acquires a plurality of signals that have different position information and are received by the receiving unit. The information processing system according to claim 1 or 2, characterized in that it is the same as described in claim 1 or 2.

4. Computers A signal acquisition step involves acquiring multiple signals received at multiple locations, A determination step for each of the aforementioned plurality of signals, which determines whether it is a satellite signal or a spoofer signal based on whether the received signal is signed or not. The determination step involves identifying multiple receiving locations where a signal determined to be a spoof signal in the determination step was received, An estimation step in which the transmission location of the spoofer signal is estimated based on the plurality of receiving locations identified in the above specific step, An output step that outputs the aforementioned transmission position, An information processing method that performs the following.

5. On the computer, A signal acquisition function that acquires multiple signals received at multiple locations, For each of the aforementioned multiple signals, a determination function is provided to determine whether it is a satellite signal or a spoofed signal based on whether the received signal is signed or not. The aforementioned determination function identifies multiple reception locations where a signal determined to be a spoof signal was received, An estimation function that estimates the transmission location of the spoofer signal based on the multiple receiving locations identified by the aforementioned specific function, An output function that outputs the aforementioned transmission position, An information processing program that makes this possible.

6. A signal acquisition unit that acquires signed satellite signals received at multiple locations, A unit that identifies the receiving location where each of the aforementioned plurality of signals was received, A reception strength acquisition unit that acquires the reception strength when each of the aforementioned plurality of signals is received, An estimation unit estimates the location of the source of the interfering radio wave whose received intensity is low, based on the location where each of the plurality of signals is received and the received intensity at that location. An output unit that outputs the aforementioned transmission position, An information processing system equipped with the following features.

7. The aforementioned information processing system is a portable or mobile terminal. A receiving unit that receives signals, The system includes a location information acquisition unit that acquires location information of the aforementioned mobile terminal, The signal acquisition unit acquires a plurality of signals that have different position information and are received by the receiving unit. The information processing system according to feature 6.

8. Computers A signal acquisition step involves obtaining signed satellite signals received at multiple locations, A selection step to identify the receiving location where each of the aforementioned multiple signals was received, A received signal strength acquisition step, which acquires the received signal strength when each of the aforementioned plurality of signals is received, An estimation step to estimate the source location of an interfering radio wave whose received intensity is low, based on the location where each of the plurality of signals is received and the received intensity at that location. An output step that outputs the aforementioned transmission position, An information processing method that performs the following.

9. On the computer, A signal acquisition function that acquires signed satellite signals received at multiple locations, A function to identify the reception location where each of the aforementioned multiple signals was received, A reception strength acquisition function that acquires the reception strength when each of the aforementioned multiple signals is received, An estimation function that estimates the source location of an interfering radio wave whose received intensity decreases, based on the location where each of the aforementioned multiple signals was received and the received intensity at that location. An output function that outputs the aforementioned transmission position, An information processing program that makes this possible.

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