Receiving apparatus, positioning information verification method, and program

Abstract

To prevent erroneous determination as spoofing.SOLUTION: The receiving device includes a receiving unit that receives satellite signals transmitted from a plurality of navigation satellites and outputs positioning information, signature information, and a carrier power-to-noise ratio for position measurement at predetermined time intervals according to the satellite signals, a storage unit that stores the time-series positioning information, signature information, and carrier power-to-noise ratio output from the receiving unit in association with each other, a verification unit that determines whether the positioning information is valid by verifying the signature information, and a verification determination unit that re-determines a failure of verification by the verification unit based on the carrier power-to-noise ratio corresponding to the positioning information and the signature information stored in the storage unit when the verification unit fails to verify the signature information.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a receiving device, a positioning information verification method, and a program. [Background technology]

[0002] A spoofed signal determination device is known that determines whether a spoofed signal is a spoofed satellite signal transmitted from a plurality of navigation satellites (see, for example, Patent Document 1). On the other hand, in order to determine whether a spoofed signal is present with higher accuracy, signature information is used to determine whether a spoofed signal is present. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6483743 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in this case, even if the actual environment is not spoofed, there is a risk that the signature verification will fail due to radio interference or the like, and the message will be erroneously determined to be spoofed.

[0005] An object of the present disclosure is to provide a receiving device, a positioning information verification method, and a program that solve any of the above-mentioned problems. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present disclosure is to a receiving means for receiving satellite signals transmitted from a plurality of navigation satellites and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in response to the satellite signals; a storage means for storing the time-series positioning information, signature information, and carrier power noise ratio output from the receiving means in association with each other; a verification means for verifying the signature information to determine whether the positioning information is valid; and a verification determination means for, when the verification means fails to verify the signature information, re-determining whether the verification by the verification means has failed based on the carrier power to noise ratio corresponding to the positioning information and the signature information stored in the storage means. Receiving device is. In order to achieve the above object, one aspect of the present disclosure is to receiving satellite signals transmitted from a plurality of navigation satellites, and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in response to the satellite signals; storing the output time-series positioning information, signature information, and carrier power to noise ratio in association with each other; a step of verifying the signature information to determine whether the positioning information is valid; If the verification of the signature information fails, re-determining the failure of the verification based on the stored carrier power noise ratios corresponding to the positioning information and the signature information; Including, Positioning information verification method is. In order to achieve the above object, one aspect of the present disclosure is to receiving satellite signals transmitted from a plurality of navigation satellites, and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in accordance with the satellite signals; a process of storing the output time-series positioning information, signature information, and carrier power noise ratio in association with each other; a process of verifying the signature information to determine whether the positioning information is valid; a process of re-determining whether the verification of the signature information has failed based on the stored carrier power to noise ratios corresponding to the positioning information and the signature information, when the verification of the signature information has failed; to the computer, program is. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a receiving device, a positioning information verification method, and a program that solve any of the above-mentioned problems. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a schematic hardware configuration of a receiving device according to the present disclosure. [Figure 2] 1 is a block diagram showing a schematic system configuration of a receiving device according to the present disclosure. [Figure 3] FIG. 10 is a diagram showing an example of navigation message information. [Figure 4] FIG. 10 is a diagram illustrating an example of the relationship between the satellite elevation angle and the carrier power to noise ratio. [Figure 5] 1 is a flowchart illustrating an example of a flow of a positioning information verification method according to the present disclosure. [Figure 6] 1 is a block diagram showing a schematic system configuration of a receiving device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 Satellite signals transmitted from navigation satellites such as quasi-zenith satellites used for positioning are subject to the threat of spoofing. The Quasi-Zenith Satellite System (QZSS) can prevent this spoofing by using a public key cryptosystem that uses signature information. However, in this case, even if a signal is not spoofed in a real environment, it may be erroneously determined to be spoofed due to a failure in signature verification caused by radio interference or other factors.

[0010] For example, if a thin object blocks the signal for a moment (0.2 to 0.5 seconds), the signal will not be received, but data will still be output. This can cause a bug when the receiver decodes the signal, resulting in some data not being decoded correctly and causing the signature verification to fail as described above.

[0011] The receiving device according to this embodiment distinguishes between erroneous spoofing decisions as described above based on the carrier-to-noise ratio (C / N0) of the satellite signal.

[0012] The receiving device is mounted on a mobile device such as a smartphone, or a mobile object such as a drone, vehicle, ship, or airplane, which detects its own position based on satellite signals transmitted from a quasi-zenith satellite, for example.

[0013] As shown in FIG. 1, the receiving device 1 of this embodiment has a hardware configuration of a typical computer, including a processor 1a such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), an internal memory 1b such as a RAM (Random Access Memory) or a ROM (Read Only Memory), a storage device 1c such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive), an input / output I / F 1d for connecting peripheral devices such as a display, and a communication I / F 1e for communicating with devices outside the device.

[0014] 2 is a block diagram showing a schematic system configuration of a receiving device 1 according to this embodiment. The receiving device 1 according to this embodiment includes a receiving unit 11, a storage unit 12, a signature verification unit 13, and a verification result determination unit 14.

[0015] Receiving unit 11 is a specific example of receiving means. Receiving unit 11 receives satellite signals transmitted from a quasi-zenith satellite, which is an artificial satellite, performs calculations for positioning, and calculates the position information of receiving device 1, carrier-to-noise ratio, satellite elevation angle, etc. Receiving unit 11 may be configured as, for example, a general modularized device. Receiving unit 11 outputs positioning information, divided signature information, satellite elevation angle, and carrier-to-noise ratio at predetermined time intervals in accordance with the received satellite signals.

[0016] The positioning information includes ephemeris data (detailed orbital information of the satellite) used for positioning. The carrier power to noise ratio indicates the magnitude of the power of the carrier wave relative to the noise, and indicates the clarity of the signal.

[0017] The predetermined time is, for example, a very short time of 0.1 seconds or less, preferably about 50 ms. Generally, the output time is about 1 second by default, and data shorter than that time, for example, every 20 ms, is averaged. Therefore, the carrier power to noise ratio during the momentary non-reception as described above is also averaged and cannot be determined. For this reason, the predetermined time is set to the very short time.

[0018] The receiver 11 outputs element signals (No. 1, 2, 3, ...) consisting of multiple subframes (Subframe 1, Subframe 2, Subframe 3, 4, ...) at predetermined intervals, as shown in Fig. 3. Each subframe includes information such as positioning information, divided signature information, ionospheric correction parameters, and the health status of the satellite.

[0019] The memory unit 12 is a specific example of a memory means. The memory unit 12 is configured, for example, by a storage device. Based on the time-series element signals output from the receiver 11, the memory unit 12 stores the positioning information, divided signature information, satellite elevation angle, and carrier power to noise ratio included in the element signals, in association with each other.

[0020] The signature verification unit 13 is a specific example of a verification means. The signature verification unit 13 generates signature information by assembling a series of a predetermined number of element signals (for example, No. 1 to No. 7) into one piece of navigation message information and assembling divided signature information included in the navigation message information.

[0021] Since the signal authentication in the quasi-zenith satellite system has a narrow bandwidth, the signature information is divided into a plurality of divided signature information and transmitted as described above. The signature information is divided into, for example, three divided signature information pieces, but is not limited to this and may be divided into four or more pieces. In this embodiment, the navigation satellite is configured as a Quasi-Zenith Satellite System (QZSS), but may be configured as a Global Navigation Satellite System (GNSS). In this case, the signature information may be transmitted from the navigation satellite without being divided.

[0022] The signature verification unit 13 verifies the generated signature information using a public key to determine whether the positioning information included in the navigation message information is valid. The public key may be set in the signature verification unit 13 or the like in advance.

[0023] If the signature verification unit 13 succeeds in verifying the signature information, it determines that the positioning information included in the navigation message information is valid. On the other hand, if the signature verification unit 13 fails to verify the signature information, it determines that the positioning information included in the navigation message information is invalid and has been spoofed.

[0024] The verification result determination unit 14 is a specific example of a verification determination means. When the signature verification unit 13 fails to verify the signature information, the verification result determination unit 14 re-determines whether the verification by the signature verification unit 13 has failed, based on the positioning information and the carrier power to noise ratio corresponding to the divided signature information.

[0025] This allows the verification result to be re-evaluated with higher accuracy based on the carrier power to noise ratio even if the signature information verification fails, preventing a false determination of spoofing due to signature verification failure caused by radio interference or the like, even though the actual environment is not spoofed.

[0026] When the signature verification unit 13 fails to verify the signature information, if the verification result determination unit 14 determines that at least one of the carrier power to noise ratios corresponding to the positioning information and the divided signature information is below a threshold, the verification result determination unit 14 determines that the verification failure by the signature verification unit 13 is an erroneous determination. The verification result determination unit 14 determines that the verification failure is not due to spoofing but is due to radio interference or the like, and determines that the positioning information included in the navigation message information is valid.

[0027] On the other hand, when the signature verification unit 13 fails to verify the signature information, if the verification result determination unit 14 determines that all of the carrier power noise ratios corresponding to the positioning information and the divided signature information are equal to or greater than the threshold, the verification result determination unit 14 determines that the verification failure by the signature verification unit 13 is correct. The verification result determination unit 14 determines that the verification failure is due to spoofing, and determines that the positioning information included in the navigation message information is invalid.

[0028] It is preferable that the threshold be set to, for example, approximately 25 to 35 dB-Hz. Generally, as the satellite elevation angle decreases, the carrier power to noise ratio also decreases. Figure 4 is a diagram showing an example of the relationship between the satellite elevation angle and the carrier power to noise ratio. Note that Figure 4 shows the above relationship for satellite signals of two different frequencies (L1, L5).

[0029] As shown in Figure 4, the carrier power to noise ratio decreases as the satellite elevation angle decreases, but it can be confirmed that even when the satellite elevation angle is 0°, the carrier power to noise ratio is greater than approximately 25 to 35 dB-Hz.

[0030] Therefore, when the signature verification unit 13 fails to verify the signature information, if the verification result determination unit 14 determines that at least one of the carrier power to noise ratios is less than the above threshold, it can determine that the verification failure is not due to spoofing but to radio interference or the like, and can determine that the verification failure is an erroneous determination.

[0031] Next, a description will be given of a method for verifying positioning information by the above-described receiving device 1. Fig. 5 is a flowchart showing an example of the flow of the method for verifying positioning information according to this embodiment.

[0032] The receiver 11 receives satellite signals transmitted from a plurality of quasi-zenith satellites, and outputs positioning information, divided signature information, and carrier power to noise ratio at predetermined time intervals in accordance with the satellite signals (step S101).

[0033] The storage unit 12 stores the time-series positioning information, divided signature information, and carrier power to noise ratio output from the receiving unit 11 in association with each other (step S102).

[0034] The signature verification unit 13 generates signature information by assembling the divided signature information stored in the storage unit 12, and verifies the signature information (step S103).

[0035] If the signature verification unit 13 fails to verify the signature information, the verification result determination unit 14 re-determines whether the verification by the signature verification unit 13 has failed based on the carrier power to noise ratio corresponding to the positioning information and the divided signature information stored in the memory unit 12 (step S104).

[0036] Embodiment 2 As shown in Fig. 4, the carrier power to noise ratio varies depending on the satellite elevation angle. Therefore, it is preferable that the verification result determination unit 14 performs the above verification determination taking into account the variation in the carrier power to noise ratio due to the satellite elevation angle. This allows for more accurate verification determination.

[0037] In this embodiment, a predetermined relational expression showing the relationship between the carrier power to noise ratio and the satellite elevation angle is set in the verification result determination unit 14. This predetermined relational expression is, for example, an approximation of a graph showing the relationship between the satellite elevation angle and the carrier power to noise ratio, as shown in Fig. 4. The approximation expression may be a linear function (y = ax + b) calculated using the least squares method or the like.

[0038] When the signature verification unit 13 fails to verify the signature information, the verification result determination unit 14 calculates the carrier power to noise ratio CN1 (hereinafter referred to as the assumed carrier power to noise ratio CN1) assumed at the satellite elevation angle based on the satellite elevation angle corresponding to the positioning information and the divided signature information and a predetermined relational expression.

[0039] If the verification result judgment unit 14 determines that at least one of the differences ΔCN between the calculated estimated carrier power to noise ratio CN1 and the carrier power to noise ratio CN2 corresponding to the positioning information and divided signature information stored in the memory unit 12 is greater than a threshold, it determines that the verification failure by the signature verification unit 13 is an erroneous judgment. ΔCN = CN1 - CN2 > threshold

[0040] On the other hand, if the verification result determination unit 14 determines that all of the differences ΔCN between the calculated estimated carrier power to noise ratio CN1 and the carrier power to noise ratio CN2 corresponding to the positioning information and divided signature information stored in the memory unit 12 are below the threshold, it determines that the verification by the signature verification unit 13 has failed as a correct determination.

[0041] Alternatively, a predetermined relational expression between the carrier power to noise ratio and the satellite elevation angle may be set for each satellite signal of a different frequency. In this case, if the signature verification unit 13 fails to verify the signature information, the verification result determination unit 14 calculates an estimated carrier power to noise ratio based on the predetermined relational expression corresponding to the satellite signal.

[0042] If the verification result determination unit 14 determines that at least one of the differences between the calculated estimated carrier power to noise ratio and the carrier power to noise ratio corresponding to the positioning information and divided signature information stored in the storage unit 12 is greater than a threshold, it determines that the verification by the signature verification unit 13 has failed as an erroneous determination. This allows for more accurate verification determination, taking into account not only the fluctuations in the carrier power to noise ratio but also the type of satellite signal.

[0043] Embodiment 3 As described above, the signature verification unit 13 generates signature information by assembling divided signature information included in the navigation message information. If an attacker rewrites the division assembly bit included in the subframe of the element signal of the navigation message information, for example, the signature verification unit 13 will not be able to assemble the divided signature information and will not be able to verify the signature information. This can essentially result in spoofing.

[0044] In contrast to this, as shown in FIG. 6, the receiving device 20 according to this embodiment further includes a spoofing detection unit 15 that detects spoofing in the generation of the signature information, in addition to the above configuration.

[0045] The spoofing detection unit 15 is a specific example of a spoofing detection means. When reception of the positioning information to be verified is completed and signature information is not generated, the spoofing detection unit 15 detects spoofing in the generation of the signature information based on the carrier power to noise ratio corresponding to the positioning information and the divided signature information. Note that the positioning information to be verified refers to the positioning information included in one piece of navigation message information.

[0046] As mentioned above, the carrier power to noise ratio decreases as the satellite elevation angle decreases, but it can be confirmed that even when the satellite elevation angle is 0°, the carrier power to noise ratio is approximately 25 to 35 dB-Hz or more. Therefore, if the carrier power to noise ratio is approximately 25 to 35 dB-Hz or more, the signature verification unit 13 should be able to receive all of the divided signature information and generate signature information. If signature information is not generated despite this, it can be assumed that spoofing of the signature information generation has occurred, as described above.

[0047] Therefore, when reception of the positioning information to be verified is completed and signature information is not generated, if the spoofing detection unit 15 determines that all of the carrier power noise ratios corresponding to the divided signature information are equal to or greater than the threshold, the spoofing detection unit 15 detects spoofing in the generation of the signature information. Note that the threshold is preferably set to approximately 25 to 35 dB-Hz.

[0048] On the other hand, when the reception of the positioning information to be verified is completed and the signature information is not generated, if the spoofing detection unit 15 determines that at least one of the carrier power noise ratios corresponding to the divided signature information is less than the threshold, the spoofing detection unit 15 does not detect spoofing in the generation of the signature information.

[0049] In addition, similarly to the above, the spoofing detection unit 15 may detect spoofing in the generation of signature information when all of the differences between the estimated carrier power to noise ratio calculated using a predetermined relational expression and the carrier power to noise ratios corresponding to the positioning information and divided signature information stored in the memory unit 12 are below a threshold value.

[0050] The receiving device 20 according to this embodiment may be configured without the verification result determination unit 14. In this case, the receiving device 20 only detects spoofing without re-determining the verification result. The spoofing detection unit 15 may calculate the expected carrier power to noise ratio using a predetermined relational expression, similar to the verification result determination unit 14.

[0051] The present disclosure can also be implemented by causing a processor to execute a computer program to perform the processing shown in FIG. 5, for example.

[0052] The program can be stored and supplied to a computer using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)).

[0053] The program may be provided to the computer by various types of transitory computer-readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer-readable media can provide the program to the computer via a wired communication path such as an electrical wire or optical fiber, or via a wireless communication path.

[0054] Each component of the receiving device 1, 20 according to the above-described embodiments can be realized not only by a program, but also in part or in whole by dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0055] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0056] Each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0057] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a receiving means for receiving satellite signals transmitted from a plurality of navigation satellites and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in response to the satellite signals; a storage means for storing the time-series positioning information, signature information, and carrier power noise ratio output from the receiving means in association with each other; a verification means for verifying the signature information to determine whether the positioning information is valid; a verification determination means for determining again whether the verification by the verification means has failed based on the carrier power to noise ratio corresponding to the positioning information and the signature information stored in the storage means, when the verification means has failed to verify the signature information; Equipped with Receiving device. (Appendix 2) 2. The receiving device of claim 1, When the verification means fails to verify the signature information, if the verification means determines that the carrier power to noise ratio corresponding to the positioning information and the divided signature information stored in the storage means is less than a threshold, the verification determination means determines that the verification failure by the verification means is an erroneous determination. Receiving device. (Appendix 3) 2. The receiving device of claim 1, the receiving means outputs the positioning information, the signature information, the carrier power to noise ratio, and the satellite elevation angle at predetermined time intervals in response to the satellite signal; a predetermined relational expression between the carrier power to noise ratio and the satellite elevation angle is set; The verification and determination means If the verification means fails to verify the signature information, calculating a carrier power noise ratio based on the satellite elevation angle corresponding to the positioning information and the signature information and the predetermined relational expression; If it is determined that the difference between the calculated carrier power to noise ratio and the carrier power to noise ratio stored in the storage means and corresponding to the positioning information and the signature information is greater than a threshold, the verification by the verification means is determined to be an erroneous determination. Receiving device. (Appendix 4) 2. The receiving device of claim 1, the receiving means outputs positioning information for position measurement, divided signature information, and a carrier power to noise ratio at predetermined time intervals in response to the satellite signal; the storage means stores the time-series positioning information, divided signature information, and carrier power to noise ratio output from the receiving means in association with each other; the verification means verifies the signature information generated by assembling the divided signature information to determine whether the positioning information is valid; When the verification means fails to verify the signature information, the verification determination means re-determines the failure of the verification by the verification means based on the carrier power to noise ratios corresponding to the positioning information and the divided signature information stored in the storage means. Receiving device. (Appendix 5) 5. The receiving device of claim 4, and a spoofing detection means for detecting spoofing in the generation of the signature information based on a carrier power to noise ratio corresponding to the divided signature information when reception of the positioning information to be verified is completed and the signature information is not generated. Receiving device. (Appendix 6) 6. The receiving device of claim 5, the spoofing detection means detects spoofing in the generation of the signature information when it determines that the carrier power to noise ratio corresponding to the divided signature information is equal to or greater than a threshold value when reception of the positioning information to be verified is completed and the signature information is not generated; Receiving device. (Appendix 7) 6. The receiving device of claim 5, a predetermined relational expression between the carrier power to noise ratio and the satellite elevation angle is set; The spoofing detection means When the reception of the positioning information to be verified is completed and the signature information is not generated, calculating a carrier power to noise ratio based on the satellite elevation angle corresponding to the positioning information and the divided signature information and the predetermined relational expression; If a difference between the calculated carrier power to noise ratio and the carrier power to noise ratio corresponding to the positioning information and the divided signature information is equal to or less than a threshold, spoofing in the generation of the signature information is detected. Receiving device. (Appendix 8) receiving satellite signals transmitted from a plurality of navigation satellites, and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in response to the satellite signals; storing the output time-series positioning information, signature information, and carrier power to noise ratio in association with each other; a step of verifying the signature information to determine whether the positioning information is valid; If the verification of the signature information fails, re-determining the failure of the verification based on the stored carrier power noise ratios corresponding to the positioning information and the signature information; Including, Positioning information verification method. (Appendix 9) receiving satellite signals transmitted from a plurality of navigation satellites, and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in accordance with the satellite signals; a process of storing the output time-series positioning information, signature information, and carrier power noise ratio in association with each other; a process of verifying the signature information to determine whether the positioning information is valid; a process of re-determining whether the verification of the signature information has failed based on the stored carrier power to noise ratios corresponding to the positioning information and the signature information, when the verification of the signature information has failed; to the computer, program.

[0058] Some or all of the elements (e.g., configurations and functions) described in Supplementary Note 2 to Supplementary Note 7 that are dependent on Supplementary Note 1 {e.g., device} may also be dependent on Supplementary Note 8 {e.g., method} and Supplementary Note 9 {e.g., program} in the same dependency relationship as Supplementary Note 2 to Supplementary Note 7. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods. [Explanation of symbols]

[0059] 1. Receiving device 1a processor 1b Internal memory 1c storage device 11 Receiving unit 12 Storage section 13 Signature Verification Unit 14 Verification result judgment unit 15 Spoofing detection unit 20 Receiving device

Claims

1. a receiving means for receiving satellite signals transmitted from a plurality of navigation satellites and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in response to the satellite signals; a storage means for storing the time-series positioning information, signature information, and carrier power noise ratio output from the receiving means in association with each other; a verification means for verifying the signature information to determine whether the positioning information is valid; a verification determination means for determining again whether the verification by the verification means has failed based on the carrier power to noise ratio corresponding to the positioning information and the signature information stored in the storage means, when the verification means has failed to verify the signature information; Equipped with Receiving device.

2. 2. The receiving device according to claim 1, When the verification means fails to verify the signature information, if the verification determination means determines that the carrier power to noise ratio corresponding to the positioning information and the signature information stored in the storage means is less than a threshold, the verification determination means determines that the verification failure by the verification means is an erroneous determination. Receiving device.

3. 2. The receiving device according to claim 1, the receiving means outputs the positioning information, the signature information, the carrier power to noise ratio, and the satellite elevation angle at predetermined time intervals in response to the satellite signal; a predetermined relational expression between the carrier power to noise ratio and the satellite elevation angle is set; The verification and determination means If the verification means fails to verify the signature information, calculating a carrier power noise ratio based on the satellite elevation angle corresponding to the positioning information and the signature information and the predetermined relational expression; If it is determined that the difference between the calculated carrier power to noise ratio and the carrier power to noise ratio stored in the storage means and corresponding to the positioning information and the signature information is greater than a threshold, the verification by the verification means is determined to be an erroneous determination. Receiving device.

4. 2. The receiving device according to claim 1, the receiving means outputs positioning information for position measurement, divided signature information, and a carrier power to noise ratio at predetermined time intervals in response to the satellite signal; the storage means stores the time-series positioning information, divided signature information, and carrier power to noise ratio output from the receiving means in association with each other; the verification means verifies the signature information generated by assembling the divided signature information to determine whether the positioning information is valid; When the verification means fails to verify the signature information, the verification determination means re-determines the failure of the verification by the verification means based on the carrier power to noise ratios corresponding to the positioning information and the divided signature information stored in the storage means. Receiving device.

5. 5. The receiving device according to claim 4, and a spoofing detection means for detecting spoofing in the generation of the signature information based on a carrier power to noise ratio corresponding to the divided signature information when reception of the positioning information to be verified is completed and the signature information is not generated. Receiving device.

6. 6. The receiving device according to claim 5, the spoofing detection means detects spoofing in the generation of the signature information when it determines that the carrier power to noise ratio corresponding to the divided signature information is equal to or greater than a threshold value when reception of the positioning information to be verified is completed and the signature information is not generated; Receiving device.

7. 6. The receiving device according to claim 5, a predetermined relational expression between the carrier power to noise ratio and the satellite elevation angle is set; The spoofing detection means calculating a carrier power to noise ratio based on the satellite elevation angle corresponding to the positioning information and the divided signature information and the predetermined relational expression; when reception of the positioning information to be verified is completed and the signature information is not generated, if a difference between the calculated carrier power to noise ratio and the carrier power to noise ratio corresponding to the positioning information and the divided signature information is equal to or less than a threshold, spoofing of the generation of the signature information is detected. Receiving device.

8. receiving satellite signals transmitted from a plurality of navigation satellites, and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in response to the satellite signals; storing the output time-series positioning information, signature information, and carrier power to noise ratio in association with each other; a step of verifying the signature information to determine whether the positioning information is valid; If the verification of the signature information fails, re-determining the failure of the verification based on the stored carrier power noise ratios corresponding to the positioning information and the signature information; Including, Positioning information verification method.

9. receiving satellite signals transmitted from a plurality of navigation satellites, and outputting positioning information, signature information, and a carrier power to noise ratio for position measurement at predetermined time intervals in accordance with the satellite signals; a process of storing the output time-series positioning information, signature information, and carrier power noise ratio in association with each other; a process of verifying the signature information to determine whether the positioning information is valid; a process of re-determining whether the verification of the signature information has failed based on the stored carrier power to noise ratios corresponding to the positioning information and the signature information, when the verification of the signature information has failed; to the computer, program.

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