JP5400529B2 - Location information authentication method and location information authentication system using a secret encryption code - Google Patents

Description

  The present invention relates to position information authentication technology in the satellite positioning field, spatial information field, navigation, location-based service field, encrypted security communication field, receiving terminal development field, and the like.

  Conventional position information is calculated by calculating latitude and longitude information from a GPS navigation message signal by a GPS receiving terminal mainly using the GPS (Global Positioning System) outdoors. In this case, the GPS position information is accurate and has been treated as credible information. However, in recent years, the development of GPS repeaters that duplicate GPS signals and GPS simulators that can artificially generate GPS behavior may lead to problems such as falsification of location information by malicious actors and impersonation of others. is there.

  Here, with regard to confirmation of position information, a position confirmation system (see Patent Document 1) capable of reliably detecting the position impersonation of the terminal device has been proposed, but the credibility and falsification of the position information itself are discussed. It has not been.

  Further, although there is a proposal for a system that authenticates position information and time information obtained from GPS or the like (see Patent Document 2), the credibility and falsification of the position information itself are not discussed. On the other hand, “Evaluation of Impersonation Threat-Study of Simple GPS Consumer Signal Impersonation” is described in detail in Non-Patent Document 1, but it describes a technique for performing encryption authentication on the navigation message (location information) itself. Absent.

Japanese Patent Publication No. 2005-80084 Japanese Patent Publication No. 2001-33537

Todd E. Humphreys “Assessing the Spoofing Threat: Development of a Portable GPS Civilian Spoofer” I0N GNSS Conference Savanna, GA, September 16-19, 2008

  Location information authentication is necessary both outdoors and indoors. First, there are several problems in outdoor location information authentication as described below.

  The first problem is to prevent the location information received from GPS itself from being falsified and spoofed by malicious actors and institutions, assuming that the location information itself is the correct location information based on the good belief. is there.

  A second problem is to provide a method for automatically and automatically identifying position information that has been falsified by a GPS repeater, a simulator, and the like and position information that has not been falsified.

  The third problem is to provide a method that regards data that does not include the characteristics of the target area regarding the effects of natural phenomena (such as ionospheric delay and tropospheric delay of message signals) as false.

  The fourth problem is to provide a reliable system that can be smoothly connected to the current operation of the existing global positioning system and local positioning system.

  On the other hand, there is only one problem indoors, and it is to obtain confirmation that the absolute position of the RFID for measuring the position is obtained from a reliable GPS.

  An object of the present invention is to provide a location information authentication method, a location information authentication system, and a location information authentication device that are provided with anti-tampering and impersonation measures in view of the current state of authenticity of location information. It is another object of the present invention to provide a safe and secure space information society by operating the above-described location information authentication method, location information authentication system, and location information authentication apparatus at an authority that possesses authentication authority.

The present invention relates to a global positioning system, and a location information authentication system that determines location information of a user segment using a local positioning system having a user segment that can decrypt a ground segment, a space segment, and a secret encryption code.
Transmitting location information including a navigation message having a secret encryption code from the space segment of the local positioning system to the user segment, and determining the location information of the user segment using the navigation message having a secret encryption code. Thus, the credibility of the position information data transmitted from the global positioning system is ensured.

  Further, when transmitting a concealed encryption code from the space segment to the user segment, the concealed encryption code is generated in the ground segment and transmitted to the space segment as a part of a navigation message, and further, the space segment To the user segment as part of a navigation message.

  In addition, when transmitting a concealed encryption code from the space segment to the user segment, the concealed encryption code is an encryption code having anti-noise properties in a navigation message of the local positioning system.

  In addition, the encryption key is used for secret generation of the encryption code in the ground segment of the local positioning system, and the encryption key that is digitally signed in the ground segment is transmitted to the user segment of the local positioning system, so that the properly verified encryption Only the user segment that can decrypt the secret encryption code using a key receives the position information data.

  In addition, the encryption key is used for the secret generation of the encryption code in the ground segment of the local positioning system, and the encryption key that is digitally signed by the authority that owns the authentication is transmitted to the user segment of the local positioning system, which is properly verified. Only a user segment that can decrypt the secret encryption code using an encryption key receives the position information data.

  In addition, only a user segment that can decrypt the concealed encryption code using a properly verified encryption key receives the location information data, so that a malicious actor including a global positioning system repeater or simulator The position information is distinguished from the falsified position information.

  Further, it is characterized in that position information data that does not include the influence of a natural phenomenon including ionospheric delay or tropospheric delay is included in the transmitted / received position information as a spoofed signal.

  In addition, the method for transmitting the encryption code to the user segment uses at least one of the existing Internet, a mobile phone system, a wireless communication system, or an existing geostationary satellite, and the method for determining and verifying the location information of the user segment includes: Any one of online processing, real-time processing with a certain time lag, or offline post-processing is used.

In addition, a global positioning system having three or more positioning satellites for transmitting positioning signals, a local positioning system having a ground segment, a space segment, and a user segment capable of decrypting a secret encryption code, and a secret encryption code In the position information authentication system for authenticating the position information of the user segment by the position information data including the navigation message, the ground segment transmitting
The ground segment of the local positioning system includes an encryption key control unit that generates an encryption key, an encryption code control unit that generates and processes an encryption code using the encryption key, and an encryption code transmission unit that transmits a secret encryption code. The position information authentication system has a program storage unit for storing a program for controlling the local positioning system.

  Further, the ground segment having a secret encryption code and encryption key generation unit used in the location information authentication system has an encryption key generation unit, an encryption code generation unit, and an encryption code processing unit. .

  Furthermore, the user segment provided with the authentication receiving terminal having the encryption code decrypting unit used in the position information authentication system has a general GNSS receiving terminal, and the authentication receiving terminal having the encryption key composite unit and the encryption code decrypting unit. It is characterized by.

  The present invention relates to a global positioning system, and a location information authentication system that determines location information of a user segment using a local positioning system having a ground segment, a space segment, and a user segment that can decrypt a secret encryption code. By transmitting position information including a navigation message having an encrypted code from the space segment of the local positioning system to the user segment, and determining the position information of the user segment using the navigation message having a secret encryption code Thus, it is possible to provide a safe and highly reliable position information authentication method and system that guarantees the authenticity of the position information data transmitted from the global positioning system and is provided with anti-tampering and impersonation measures.

It is a schematic diagram which shows the basic composition of this invention location information authentication system. It is a system block diagram which shows the encryption production | generation apparatus of this invention location information authentication system. It is explanatory drawing which shows the format of the navigation message of a prior art example. It is explanatory drawing which shows the format of the navigation message of this invention. It is a flowchart of the encryption key and encryption code generation algorithm of this invention. It is a system block diagram which shows the encryption key sending method of this invention location information authentication system. It is a flowchart of the encryption key and encryption code authentication algorithm of this invention. It is explanatory drawing at the time of sending the encryption key of this invention to the position authentication receiving terminal. It is explanatory drawing of the authentication database of this invention. It is a schematic diagram which shows the countermeasure against the impersonation signal using the natural phenomenon of this invention. It is a schematic diagram which shows the management operation system and method of this invention.

  First, an embodiment that solves the problem will be described in detail with respect to an embodiment that realizes the reliability of position information, which is the first problem of the present invention.

[Positioning calculation]
Transmission / reception of a secret encryption code according to the first embodiment will be described with reference to FIG. Among the three or more GPS satellite groups 10, navigation messages 11, 12 or 13 each of which includes positioning information from the GPS satellites 111, 112, and 113 are included in the user segment 3 of the local positioning satellite system. Is received by the authentication receiving terminal 30 with the encryption code decrypting unit. The position measurement calculation at the authentication receiving terminal 30 requires position information from at least four or more satellites.

  The local positioning satellite 100 is used as the fourth satellite. The local positioning satellite system includes, for example, a quasi-zenith satellite system (QZSS) or a satellite-based reinforcement system for providing reinforcement information via a geostationary satellite. MTSAT Satellite-based Augmentation System (hereinafter referred to as MSAS) is conceivable. The positioning local satellite system of the present invention can be used in any one of QZSS, MSAS, or any apparatus having an equivalent function.

  The navigation message 21 transmitted from the space segment 1 of the local positioning satellite system has the same content as the GPS navigation message 11, 12 or 13.

The secret encryption code and encryption key generation unit 20 included in the ground segment 2 of the local positioning satellite system includes a local positioning satellite encryption code control unit 200, an encryption code reception unit 210, an encryption code transmission unit 220, and an encryption key control. Section 230, encryption code generation section 240, encryption code processing section 250, encryption key preprocessing section 260, and antenna section 270.
[Concealed encryption code]
Here, a navigation message obtained by adding a secret encryption code to the navigation message 21 is represented by 22. For example, the encryption code control unit 200 performs encryption code processing on the encryption code of the ground segment 2 and the navigation message input to the encryption code reception unit 210 of the encryption key generation unit 20. Things are possible.

The navigation message 22 to which the encryption code concealed by the encryption code control unit 200 is added is processed into a GPS signal by the encryption code transmission unit 220, and the antenna unit 270 is used as the navigation message 22 to which the encryption code and the parity bit are concealed. To the space segment 1.
[Authentication of navigation messages]
The user segment 3 of the local positioning satellite system has an authentication receiving terminal 30, and the authentication receiving terminal 30 includes a general GNSS receiving terminal 31 and an encryption code decrypting unit 310 of the present invention. In the GNSS receiving terminal 31, the positioning calculation is executed by the GPS navigation messages 11, 12, 13 and the navigation message 21 transmitted from the space segment 1 of the local positioning satellite system. This is a general positioning calculation.

  On the other hand, in the encryption code decryption unit 310, the navigation message 22 to which the secret encryption code is added becomes the decrypted navigation message 23 with authentication. Based on the GPS navigation messages 11, 12, 13, and 21 and the navigation message with authentication 23, the positioning calculation with authentication is executed by the positioning calculation processing unit 320 for authentication. The encryption code decryption unit 310 of the user segment 3 ensures that navigation messages of four or more satellites received as positioning signals have not been tampered with.

At this time, the authentication receiving terminal 30 only needs to support a so-called GNSS (Global Navigation Satellite System), and is not limited to GPS. It may be a receiving terminal that can receive the navigation message. Here, GPS is mentioned as an example.
[Generation of encryption key]
Next, a configuration in the case of adopting an encryption key used for secret generation and a temporally changing value as the encryption key will be described with reference to FIG.

  As a key used for secret generation of an encryption code, for example, a secret encryption code and the clock 201 of the encryption key generation unit 20 can be used. The clock 201 is a clock unique to the device, and a certain sampled time is different from other times and a unique value is obtained.

  Assume that the sampling time is t2001. The time t2001 is input to the encryption key generation unit 231 of the encryption key control unit 230 in the encryption code control unit 200, and a unique integer (hereinafter referred to as SEED Value) is generated using a predetermined logic. As an example of the predetermined logic, a mathematical function widely used in scientific and engineering calculations can be used. It is also possible to generate a random number based on probability theory as another SEED Value generation source. In any case, it is important to irregularly generate a unique integer value as the SEED Value, and the means is not limited to the above means.

  Using the generated SEED Value, the random matrix calculation unit 241 of the encryption code generation unit 240 performs N × M matrix calculation. Thereafter, the H-matrix calculation unit 242 of the encryption code generation unit 240 generates an H-matrix of input N bits and output bits M bits. In general, the navigation message 21 is a requirement specification ICD-GPS-200 ver. Defined in D. Here, the global positioning system (GPS) requirement specification ICD-GPS-200 ver. From D, N = 90 and M = 180.

  Here, an example of the format of the navigation message 21 and the format of the navigation message 22 proposed this time will be described with reference to FIGS. 3A and 3B. FIG. 3A shows a conventional format, and FIG. 3B shows a format of the present invention.

3A and 3B, one navigation message is composed of five frames, one frame is composed of five subframes, and one subframe is composed of a plurality of words. Here, the first 6 words of subframe 1 will be described in detail. The first six words are word 1 (W1) 2101, word 2 (W2) 2102, word 3 (W3) 2103, word 4 (W4) 2104, word 5 (W5) 2105, and word 6 (W1) 2106, respectively. Each word is composed of 30 bits. The first three words, word 1 (W1) to word 3 (W3), contain valid information bits. On the other hand, the remaining three words, word 4 (W4) to word 6 (W6), are reserved bits.
[Generation of a secret encryption code]
In order to generate a secret encryption code, which is an object of the present invention, LDPC encoding is performed on 90 bits of the first three words in one subframe of the navigation message 21. LDPC is an abbreviation for Low Density Parity Check, and is a low density parity check code that belongs to an error correction block code and is classified as a sparse graph code. The feature is the first error correction code that is strong in the reproducibility to the lack of data and the strength of the parity error, and achieved a rate very close to the Shannon limit, which is the theoretical limit value of the information transmission rate. It is a highly reliable error correction code that is already used in the standard WiMAX or the like.

  In FIG. 3B, the first three words of word 1 (W1) 2101 to word 3 (W3) 2103 of input navigation message 21 are subjected to LDPC encoding by encryption code control unit 200, and words of 6 words of output navigation message 22 are output. 1 (W1) 2201 to word 6 (W6) 2206 are obtained. At this time, the output navigation message 22 is a secret encryption code, but due to the characteristics of LDPC encoding, the bit arrangement of the words 2101 and 2201 is invariant. That is, identity is maintained before and after encoding. This can also be applied to the words 2102 and 2202 and the words 2103 and 2203.

  In FIG. 2 again, the 90 bits of the first frame of the navigation message 21 from the navigation message 21 generated by the master control station, which is the input data of the encryption code receiving unit 210, are converted into the secret encryption code and encryption key of the local positioning satellite. The data is input to the encryption code processing unit 250 in the encryption code control unit 200 in the generation unit 20.

  The 90 bits of the first frame of the navigation message input here are subjected to LDPC encoding embedding processing by the encryption code embedding unit 251 of the encryption code processing unit 250, and at the same time, parity calculation is performed by the anti-noise reinforcement unit 252. 90 bits of parity bits are generated.

  The LDPC encoding and embedding process is performed by an algorithm program stored in the program storage unit 253 of the encryption code embedding unit 251. Similarly, the parity calculation process is performed by an algorithm program stored in the program storage unit 254 of the anti-noise reinforcement unit 252.

The 90 bits of the first frame of the navigation message generated by the above processing become a secret encryption code, and the subsequent 90 bits become a parity bit. The secret encryption code 90 bits and the subsequent 90 parity bits are sent to the transmission processing unit 221 in the encryption code transmission unit 220. The transmission processing unit 221 transmits the secret encryption code and the navigation code 22 added with the parity bit from the antenna unit 270 of the local positioning system to the space segment 1 of the local positioning system.
[Send encryption key]
On the other hand, the encryption key 202 generated by the encryption key generation unit 231 in the encryption key control unit 230 is sent to the encryption key preprocessing unit 260. The encryption key preprocessing unit 260 includes an encryption key encapsulating unit 261 and a transmitting unit 262 of the encapsulated and protected encryption key 203.

  Here, an example of an algorithm for generating an encryption code and an encryption key according to the present invention will be described in detail with reference to the flowchart of FIG.

  First, the secret encryption code and encryption key generator 20 of the local positioning satellite receives the GPS signal in step S2, and determines authentication in step S3. When authenticating, the navigation message 21 is received in step S4. In step 5, SEED Value is received, and encryption encoding of the navigation message 21 is started in step S6. In step S7, an H-matrix is generated. Next, LDPC encoding is calculated in step S8, and a parity check is calculated in step S9. In step S10, the navigation message 22 is uplinked to the space segment 1. In step Sll, it is determined whether or not the transmission of the SEED Value is complete. If completed, the process ends in step S12.

If the transmission is incomplete, the SEED Value is encoded in step S13, the communication means is selected in step 14, and the authentication database is accessed in step 15.
[Location authentication at the authentication receiving terminal]
Finally, with reference to the system block diagram of FIG. 5, the details of the configuration in which only the authentication receiving terminal to which the encryption key is sent by the electronic signature are authenticated when the encrypted encryption code is decrypted by the authentication receiving terminal 30 will be described in detail. Describe.

  The encapsulation here means that the encryption key 202 is provided with a header or the like and transmitted to the authentication authority owning organization 40 in order to enable encryption by IPsec, SL communication, public key or satellite augmentation signal in VPN communication. Assume processing. As a communication medium when the authentication receiving terminal 30 receives the encapsulated encryption key 203, the Internet 511, the existing mobile phone network 512, the existing wireless LAN 513, and the existing geostationary satellite 514 can be used.

  Depending on the characteristics of each communication medium, it is considered from the technical, cost, and operational aspects whether IPsec, SSL communication, public key, or encryption using a reinforcement signal is suitable. A plurality of proposals that are effective from the viewpoint of securely and securely sending the encapsulated encryption key 202 to the authentication receiving terminal 30 will be described.

  An example is encryption using IPsec, SSL communication, public key, or satellite reinforcement signal. The encapsulated encryption key 203 is input to the communication means distribution function unit 410 in the authentication authority possessing organization 40. The communication means distribution function unit 410 allocates the encryption key 203 to the encryption key encryption unit 430 according to the electronic signature means. The encryption key 203 is allocated to, for example, the IPsec encryption unit 431 of the encryption key encryption unit 430, the SSL communication encryption unit 432, the encryption unit 433 using a public key, or the encryption unit 434 using a satellite reinforcement signal. The database referred to at this time is the authentication database 420.

  The encryption key encryption unit 430 is uniquely connected to the corresponding network in the communication medium 50 by the assigned communication means. That is, the IPsec encryption unit 431 connects to the IPsec decryption unit 331 of the encryption key decryption unit 330 in the authentication receiving terminal 30 via the Internet VPN connection 511. Similarly, the SSL communication encryption unit 432 is connected to the SSL communication decryption unit 332 of the encryption key decryption unit 330 in the authentication receiving terminal 30 via the mobile phone network 512. The public key encryption unit 433 is connected to the public key decryption unit 333 of the encryption key decryption unit 330 via the wireless LAN network 513. The satellite encryption unit 434 is connected to the satellite decryption unit 334 of the encryption key decryption unit 330 via the satellite function network 514.

  Here, as a representative example, the encryption, communication, decryption, and positioning calculation results by IPsec and the positioning calculation result by the general GNSS receiving terminal 31 will be described in detail. In the encryption key decryption unit 330 in the authentication receiving terminal 30, the decrypted encryption key 300 output from the IPsec decryption unit 331 is input to the encryption code decryption unit 310.

  The encryption code decrypting unit 310 performs decryption processing using the encryption key 300 using the secret navigation message 22 with the encryption code code as input data, and outputs decryption data 23 that is an authenticated navigation code message.

  The latitude / longitude altitude is calculated by the authentication positioning calculation processing unit 320 based on the decoded data 23, the navigation message 11 by the GPS satellite 111, the navigation message 12 by the GPS satellite 112, and the navigation message 13 by the GPS satellite 113, and the authenticated positioning result output. 302 is calculated.

On the other hand, since the general GNSS receiving terminal 31 does not have an encryption code decryption function, the navigation message 22 with a secret encryption code is regarded as a general GPS signal without guarantee of position authentication. The general GNSS receiving terminal 31 uses the navigation message 22 imitating a general GPS signal, the navigation message 11 by the GPS satellite 111, the navigation message 12 by the GPS satellite 112, and the navigation message 13 by the GPS satellite 113 at the positioning calculation processing unit 340. Calculate the latitude and longitude altitude. However, the output positioning result is a general positioning result output 301, which is an uncertain positioning result whose position information is not authenticated.
[Encryption key / encryption code generation algorithm]
Here, an example of an algorithm for authenticating the encryption key and the encryption code of the present invention will be described in detail with reference to the flowchart of FIG. 6 regarding the operation of the authentication receiving terminal 30 of FIG.

  This authentication algorithm is basically reversible with the encryption key and encryption code generation algorithm detailed in FIG. First, the authentication receiving terminal 30 receives a GPS signal in step S21, and determines authentication in step S22. When authenticating, the navigation message 22 is received in step S23. When the general GNSS receiving terminal 31 performs the positioning calculation without authentication, the process proceeds to step S31 described later.

  In step S24, the SEED Value decrypted in step S25 is received. In step S26, an H-matrix is generated. In step S27, LDPC encoding is calculated. In step S28, a parity check is calculated. The navigation message 23 decrypted in step S29 is obtained. If the navigation message 23 decoded in step S30 and the W4, 5, 6 of the navigation message 22 match, the process proceeds to step S31. If they do not match, the process returns to step S36 to generate the H-matrix again.

In step S31, it is determined whether or not positioning calculation is performed. If positioning calculation is not necessary, the process ends in step S35. When performing the positioning calculation, other GPS signals 11, 12, 13, and 14 are received in step S32, and if the received signal is a signal from four satellites in step S33, the positioning calculation is performed in step S34. If the number of satellites is less than 4, the process returns to step S32 to set the number of satellites to 4 or more.
[Encryption key sending step]
Here, an example of a time-series change in the process of sending the encryption key of the present invention to the location authentication receiving terminal with various electronic signatures will be described in detail using the explanatory diagram of FIG. Based on the flow of this time-series change, the configuration that ensures the credibility of the position information data transmitted from the GPS will be clarified.
(1) The encryption key 203 is generated in the secret encryption code of the ground segment 2 and the encryption key preprocessing unit 260 in the encryption key generation unit 20. In step S41, the encryption key 203 is sent to the authentication authority possessing organization 40 in accordance with the interval for uplinking the encryption code which is the navigation message 22 to which the encryption code concealed with the parity bit is added.
(2) In the communication means distribution unit 410 in the authentication authority possessing institution 40, communication processing means are selected for online, near real time, and offline in step S42. Because the uplink interval is 4 hours in the current global positioning system (GPS) and the planned local positioning system, the secret encryption code and encryption key generator 20 in the local positioning satellite A time lag occurs until the navigation message 22 with the secret encryption code uploaded from the encryption code transmission unit 220 is reflected in the navigation message 21 transmitted from the space segment 1 of the positioning local satellite system.
(3) In order to minimize the time lag and to provide a highly reliable location information authentication system, in the authentication database 420, the transmission time of the encryption key 203 and the communication means are recorded based on the uplink time in step S43. To do.
(4) Select an encryption means. In step S44, the encryption key encryption unit 430 selects IPsec, SSL communication, and encryption of the encryption key 203 using a public key. The selection criteria can be selected by any method according to the convenience to the user. From the past achievements and the characteristics of each network communication medium, IPsec tends to be frequently used in wireless LAN, Internet VPN connection for SSL, packet network connection for mobile phone, and encryption by public key. However, the communication means is not fixed or guided as described above, and there can be various options such as future technological development, cost, convenience, and reliability.
(5) In step S45, the encryption key decryption unit 330 in the authentication receiving terminal 30 selects IPsec, SSL communication, and decryption of the encryption key 203 using the public key. It is preferable to select a decryption unit corresponding to the encryption unit selected in (4).
(6) The encryption code decrypting unit 310 in the authentication receiving terminal 30 with the encryption code decrypting unit decrypts the encrypted code using the encryption key 300 decrypted in step S46, and generates an authenticated navigation message.

The above-described flow of time series change clarifies the configuration that ensures the credibility of the position information data transmitted from the GPS.
[Authentication database]
Here, an example of the data structure of the authentication database 420 will be described in detail with reference to FIG. In FIG. 8, the abscissa indicates the encryption key 203, the generation time of the device clock 201, the encryption means, the communication means using the network medium 50, and the uplink time. This will be described in detail based on the data in the first column.

  The encryption key “9864398” was calculated from the generation time “2009012202356” by the clock 201 of the apparatus. The encryption means “IPsec” is selected, and the communication means is “Internet”. The uplinked time is “200901129202400”. This time can be the UTC adopted by GPS, and may conform to the atomic clock mounted on the local positioning satellite space segment, and in any case, if there is no contradiction in this system as the standard time Good. Here, it is assumed to be UTC.

  Similarly, in the data described in the second column, the generation time is “200901292162342” which is different from that of the first column, but the uplink time is the same as “20090129202400” in the first column. As described above, since the uplink interval is every 4 hours as described above, the uplink time “200901129162400” described in the second column is the latest time, and the generation time in the second column This is because the latest uplink time was not in time. As can be seen from the above, depending on the uplink time lag interval, the processing means for processing the digitally signed encryption key includes either online processing, real-time processing with a certain time lag, or offline post-processing. .

[Identification of falsification information]
With reference to FIG. 9, a detailed description will be given of what means is used to distinguish between position information altered by a GPS repeater, a simulator, and the like, which is the second problem of the present invention, and position information not altered.

  The second embodiment is a configuration for prohibiting retransmission of a received signal by a GPS repeater or a simulator. That is, the difference between the retransmit signal and the original signal is automatically and implicitly identified. When the navigation receiver 62 is received by the authentication receiving terminal 30 as the location information falsified by the malicious simulator 6 by the GPS simulator 620, an encryption code that periodically changes is added to the navigation message 62 in the decryption unit 310. Therefore, the authentication receiving terminal 30 determines that the navigation message 62 is a false signal.

  In other words, implicitly the difference between the navigation message 62 signal, which is the position information transmitted by the GPS simulator 620 and maliciously altered, and the original signal of the navigation message 22 with the secret encryption code and the parity bit added, Can be recognized automatically.

[Influence of natural phenomena]
The identification of tampering due to natural phenomena (ionospheric delay, tropospheric delay, etc.), which is the third problem of the present invention, will be described in detail with reference to FIG.

  The third embodiment is a countermeasure against impersonation signals that considers data that does not include the characteristics of the region (effects of ionospheric delay, troposphere delay, etc.) due to the natural phenomenon of position as false. The navigation messages 11, 12, 13, and 14 transmitted from the GPS 111, GPS 112, GPS 113, and GPS 114 by the ionospheric delay group 1100 and the tropospheric delay group 1200, which are representative examples of delays due to natural phenomena, are navigation messages 1301 with a delay. 1302, 1303, and 1304. The relationship between 11 and 1301 is 1301 = 11 + 1101 + 1201.

  Here, the ionospheric delay 1100 and the tropospheric delay 1200 are delay components at a point where the GPS 111 exists. The following description can be made in the same manner as 1302 = 12 + 1102 + 1202, 1303 = 13 + 1103 + 1203, 1304 = 14 + 1104 + 1204.

  By detecting the natural variation component at the observed point from the relational expression between the navigation message 1301 with delay and the navigation code 11 without delay, the navigation message 61 does not include the natural phenomenon of the region. Is found to be a navigation message played by a fake GPS repeater 610.

  The GPS repeater 610 repeats the navigation message 11 received from the GPS 111 and transmits it as a signal 61. In this case, the position determination calculation is performed at the authentication receiving terminal 30 by the direct messages 12 and 13 from the GPS and the spoofed signal 61 by the GPS repeater 610 and the navigation message 22 to which the secret encryption code and the parity bit are added.

  The navigation message 1301 by the original GPS 111 is accompanied by an ionospheric delay 1100 including 1101 to 1104 due to passing through the ionosphere 110 due to a natural phenomenon, and a tropospheric delay 1200 including 1201 through 1204 due to passing through the troposphere 120. . However, since the spoofed signal 61 generated by the GPS repeater 610 does not include these ionospheric delay 1100 and tropospheric delay 1200 which are natural phenomena, it is clearly not a navigation message 1301 transmitted from the original GPS 111 by comparing the two. It turns out.

  FIG. 10 is used to explain how smoothly and continuously the current operation of the existing global positioning system (GPS) and the local positioning system, which is the fourth problem of the present invention, can be made a reliable system. Detailed description.

  The fourth embodiment proposes a system in which a secret encryption code is embedded in the navigation code of the GPS and the local positioning satellite in the target area, and the authority-owning authority manages and manages the position guarantee.

  Signals transmitted from the GPS satellite group 10 and the space segment 1 of the local positioning satellite system are received by the positioning monitor station 70 in the ground segment 2 of the local positioning satellite system.

  The positioning monitor station 70 transmits a reception signal to the master control station 80 and transmits a navigation message or the like in the navigation message generation unit 83 via the positioning system control unit 81 and the orbit time estimation prediction unit 82 in the master control station 80. In addition, the navigation message 21 transmitted from the space segment 1 from the tracking control station 90 is transmitted to the space segment 1 of the positioning local satellite system. At this time, a navigation message to which a secret encryption code and a parity bit are added is generated by the secret encryption code and encryption key generation unit 20 of the local positioning satellite in the tracking control station 90, and the space segment 1 of the local positioning satellite system. Uplink.

  FIG. 10 shows an example in which a location information authentication authority possessing organization 40 is provided in the ground segment 2 of the local positioning satellite system. The authorized authority 40 does not necessarily have to exist in the terrestrial segment 2 of the positioning local satellite system.

  The encryption key 202 is periodically generated by the secret encryption code and encryption key generation unit 20 of the local positioning satellite and becomes the encryption key 400 encrypted by the authentication authority owning organization 40, and is locally transmitted via the communication medium 50. In the authentication receiving terminal 30 with an encryption code decryption unit in the user segment 3 of the positioning satellite system, the encrypted encryption key 300 becomes a decrypted encryption key 300 and is transmitted by decrypting the navigation message 22 with the secret encryption code and parity bit added. The authenticity of the signal is guaranteed.

DESCRIPTION OF SYMBOLS 1 ... Space segment of local positioning satellite system, 10 ... GNSS satellite group, 11 ... Navigation message by GPS satellite 111, 12 ... Navigation message by GPS satellite 112, 13 ... Navigation message by GPS satellite 113, 14 ... By GPS satellite 114 Navigation message, 100 ... local positioning satellite, 110 ... ionosphere, 120 ... troposphere, 1100 ... ionosphere delay group, 1200 ... troposphere delay group, 1301-1304 ... navigation message by GPS satellite with delay due to natural phenomenon,
2 ... ground segment of local positioning satellite system, 20 ... secret encryption code and encryption key generator, 21 ... navigation message transmitted from space segment, 22 ... navigation message with secret encryption code and parity bit added, 23 ... Decrypted data, 200 ... Encryption code control unit, 201 ... Clock, 202 ... Encryption key, 203 ... Encapsulated encryption key, 210 ... Encryption code reception unit, 211 ... Encryption code reception control unit, 220 ... Encryption code transmission , 221 ... encryption code transmission control unit, 230 ... encryption key control unit, 231 ... encryption key generation unit, 240 ... encryption code generation unit, 241 ... random matrix calculation unit, 242 ... H-matrix calculation unit, 250 ... encryption code Processing unit 251... Encryption code embedding unit 252. Reinforcement unit, 253... Encryption code embedding program storage unit, 254 .. against noise reinforcement program storage unit, 260... Encryption key pre-processing unit, 261... Encryption key encapsulation unit, 262. 270 ... the antenna part of the ground segment 20,
DESCRIPTION OF SYMBOLS 3 ... User segment of local positioning satellite system, 30 ... Authentication receiving terminal with encryption code decoding part, 31 ... General GNSS receiving terminal, 300 ... Decrypted encryption key, 301 ... General positioning result output, 302 ... Authenticated Positioning result output 310 ... encryption code decryption unit 320 ... authentication positioning calculation processing unit 330 ... encryption key decryption unit 331 ... IPsec decryption unit 332 ... SSL communication decryption unit 333 ... public key decryption unit 334 DESCRIPTION OF SYMBOLS Decoding unit by satellite, 340 ... Positioning calculation processing unit 40 ... Authorized authority organization, 400 ... Encrypted encryption key, 410 ... Communication means distribution function unit, 420 ... Authentication database, 430 ... Encryption key encryption unit, 431... IPsec encryption unit, 432. SSL communication encryption unit, 433. Public key encryption unit, 434. Satellite encryption unit, 50. 511 ... Internet VPN connection, 512 ... cell phone network, 513 ... wireless LAN network, 514 ... satellite network, 6 ... malicious actor, 60 ... pseudo signal generator, 61 ... retransmitted spoof signal by GPS simulator Navigation message by 62, Navigation message by retransmitted spoof signal by GPS repeater, 610 ... GPS simulator, 620 ... GPS repeater

Claims (15)

In a global positioning system, a location information authentication system that determines location information of a user segment using a local positioning system having a user segment that can decrypt a ground segment, a space segment, and a secret encryption code,
Transmitting position information including a navigation message having a concealed encryption code from the space segment of the local positioning system to the user segment, determining position information of the user segment using a navigation message having a concealed encryption code , Only a user segment that can decrypt the concealed encryption code using an encryption key can receive the position information data, and is distinguished from position information altered by a malicious actor including a global positioning system repeater or a simulator. By doing so, the authenticity of the positional information data transmitted from the said global positioning system is ensured, The positional information authentication method characterized by the above-mentioned. In the location information authentication method according to claim 1,
When transmitting a concealed encryption code from the space segment to the user segment, the concealed encryption code is generated in the ground segment and transmitted to the space segment as part of a navigation message, and further navigation from the space segment. A location information authentication method, wherein the location information authentication method is transmitted to the user segment as a part of a message. In the location information authentication method according to claim 1,
Location information authentication characterized in that when transmitting a secret encryption code from the space segment to the user segment, the secret encryption code is an anti-noise encryption code in a navigation message of the local positioning system. Method. In the location information authentication method according to claim 1,
An encryption key is used for secret generation of the encryption code in the terrestrial segment of the local positioning system, and an encryption key digitally signed in the terrestrial segment is transmitted to the user segment of the local positioning system. A location information authentication method, wherein only the user segment that can decrypt the concealed encryption code using the location information receives the location information data. In the location information authentication method according to claim 1,
The encryption key is used for the secret generation of the encryption code in the ground segment of the local positioning system, and the encryption key digitally signed by the authority that owns the authentication is transmitted to the user segment of the local positioning system to verify the encryption A location information authentication method, wherein only a user segment that can decrypt the secret encryption code using a key receives the location information data. In the location information authentication method according to claim 4 or 5,
A position information authentication method characterized in that position information data that does not include an influence of a natural phenomenon including ionospheric delay or tropospheric delay is included in the transmitted / received position information as a spoofed signal. In the location information authentication method according to any one of claims 1 to 6 ,
The method of transmitting the encryption code to the user segment uses at least one of the existing Internet, a mobile phone system, a wireless communication system, or a geostationary satellite, and the method for determining and verifying the location information of the user segment includes online processing A location information authentication method using either real-time processing with a certain time lag or off-line post-processing. A global positioning system having three or more positioning satellites for transmitting positioning signals, a local positioning system having a user segment with a receiving terminal capable of decoding a ground segment, a space segment, and a secret encryption code, and In the location information authentication system for authenticating the location information of the user segment with the location information data including the navigation message, the ground segment transmitting the encrypted code,
The ground segment of the local positioning system includes an encryption key control unit that generates an encryption key, an encryption code control unit that generates and processes an encryption code using the encryption key, and an encryption code transmission unit that transmits a secret encryption code. , said to have a program storage unit for storing a program for controlling the local positioning system, only the receiving terminal that allows decrypting the concealed encrypted code is to be received as the position information are not tampered with the positional information data Thus, the position information authentication system is characterized in that the position information is distinguished from position information altered by a malicious actor including a global positioning system repeater or a simulator . In the location information authentication system according to claim 8 ,
When transmitting a navigation message including a secret encryption code from the space segment to the user segment, the ground segment encryption code control unit includes an encryption code generation unit and an encryption code processing unit for processing the generated encryption code The encryption code processing unit further includes an encryption code embedding unit having an algorithm for embedding the encryption code in the navigation message, and a program storage unit for storing a program for controlling the encryption code embedding unit. Information authentication system. In the location information authentication system according to claim 9 ,
When transmitting a concealed encryption code from the space segment to the user segment, the encryption code processing unit includes an anti-noise reinforcing unit having an algorithm for realizing anti-noise properties of navigation messages of the local positioning system, and A position information authentication system comprising a program storage unit for storing a program for realizing noise resistance of a navigation message. In the location information authentication system according to claim 8 ,
The terrestrial segment of the local positioning system has transmission means for transmitting an encryption key used for secret generation of the encryption code digitally signed in the terrestrial segment to the user segment of the local positioning system, and the user segment is An authentication receiving terminal having an encryption code decrypting unit for decrypting the concealed encryption code using a properly verified encryption key, and only the authentication receiving terminal can receive the location information data. Feature location information authentication system. In the location information authentication system according to claim 9 ,
The ground segment of the local positioning system has a transmission means for transmitting the encryption key used for secret generation of the encryption code digitally signed by an authority authorized to the user segment of the local positioning system, and the user segment Has an authentication receiving terminal having an encryption code decrypting unit for decrypting the concealed encryption code using a properly verified encryption key, and only the authentication receiving terminal can receive the location information data. A location information authentication system. In the location information authentication system according to claim 11 or 12 ,
A position information authentication system comprising: an authentication receiving terminal that regards position information data that is not affected by a natural phenomenon including ionospheric delay or tropospheric delay in the transmitted / received position information as a spoofed signal. In the location information authentication system according to claim 11 or 12 ,
The communication means for transmitting the encryption key with the electronic signature to the user segment of the local positioning system uses at least one of the existing Internet, a mobile phone system, a wireless communication system, or a geostationary satellite. The position information authentication system is characterized in that the determination and verification of the position information uses any of online processing, real-time processing with a certain time lag, and offline post-processing. 9. The location information authentication system according to claim 8 , wherein the authentication receiving terminal of the user segment has an encryption key decryption unit that ensures the authenticity of the location information data by decrypting the encrypted encryption code. A location information authentication system.

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