Positioning system and positioning method

Abstract

To provide a positioning device of a simple constitution capable of performing authenticity determination and positioning at high speed, and reducing cost.SOLUTION: This system is provided with a base station for storing the position of its own station beforehand and a positioning device for performing positioning. The base station determines a true navigation message by using the fact that the received positioning signal and the position of the own station stored in advance are the same. The base station compression message generation unit generates a base station compression message by compressing a true navigation message. The base station communication unit transmits the base station compression message. The positioning device receives the base station compression message. The verification compressed message generation unit generates a verification compressed message by compressing a navigation message of a received positioning signal. The determination part collates the base station compressed message with the compressed message for verification to determine the authenticity of the received navigation message. The positioning part positions the position of the positioning device by using the positioning signal whose received navigation message is true.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This relates to positioning technology using positioning signals broadcast from GNSS satellites. [Background technology]

[0002] Patent Documents 1 and 2 describe techniques for determining the authenticity of a positioning signal using a digital signature and a hash value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6213258 specification [Patent Document 2] US Patent Application Publication No. 2023 / 0209352 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when using digital signatures and hash values, the computational load for determining authenticity increases, which means that a high-performance processing unit is required to achieve real-time authentication and positioning, making it difficult to realize a positioning device with a simple configuration that can be reduced in cost.

[0005] Therefore, an object of the present invention is to realize a positioning device that can perform authenticity determination and positioning at high speed, and has a simple configuration that can be reduced in cost. [Means for solving the problem]

[0006] A positioning system according to an embodiment of the present invention includes a positioning satellite that broadcasts a positioning signal including a navigation message, a base station that stores its own position in advance, and a positioning device that performs positioning.

[0007] The base station includes a base station positioning unit, a determination unit, a base station compressed message generation unit, and a base station communication unit. The base station positioning unit calculates the position of the base station using the received positioning signal. The determination unit determines the true navigation message by determining whether the calculated base station position is the same as the pre-stored position of the base station. The base station compressed message generation unit compresses the true navigation message to generate a base station compressed message. The base station communication unit transmits the base station compressed message.

[0008] The positioning device includes a device communication unit, a verification compressed message generation unit, a determination unit, and a positioning unit. The device communication unit receives a base station compressed message. The verification compressed message generation unit compresses a navigation message of a received positioning signal to generate a verification compressed message. The determination unit compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic. The positioning unit calculates the position of the positioning device using a positioning signal for which the received navigation message is authentic.

[0009] This configuration allows for easy computational processing to determine authenticity using compressed navigation messages, enabling high-speed authentication and positioning, and realizing a positioning device with a simple configuration that can be reduced in cost.

[0010] A positioning system according to an embodiment of the present invention includes a base station that stores its own time in advance, and a positioning device that performs positioning.

[0011] The base station includes a base station time calculation unit, a base station determination unit, a base station compressed message generation unit, and a base station communication unit. The base station time calculation unit calculates the base station time using the received positioning signal. The base station determination unit determines the true navigation message by determining whether the calculated base station time is the same as the base station's own time stored in advance. The base station compressed message generation unit compresses the true navigation message to generate a base station compressed message. The base station communication unit transmits the base station compressed message.

[0012] The positioning device includes a device communication unit, a verification compressed message generation unit, a device determination unit, and a positioning unit. The device communication unit receives a base station compressed message. The verification compressed message generation unit compresses the navigation message of the received positioning signal to generate a verification compressed message. The device determination unit compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic. The positioning unit calculates the position of the positioning device using the positioning signal for which the received navigation message is authentic.

[0013] This configuration allows for easy computational processing to determine authenticity using compressed navigation messages, enabling high-speed authentication and positioning, and realizing a positioning device with a simple configuration that can be reduced in cost.

[0014] In a positioning system according to an embodiment of the present invention, a base station positioning unit calculates the position and time of a base station using a received positioning signal, and a base station determination unit determines a true navigation message by further using the fact that the calculated base station time is the same as the base station's own time stored in advance.

[0015] In this configuration, both the position coordinates and the time are used, so authenticity can be determined more accurately.

[0016] A positioning system according to one embodiment of the present invention comprises a positioning satellite that broadcasts a positioning signal including a navigation message, a plurality of base stations each of which stores its own position in advance, a management base station that manages the plurality of base stations, and a positioning device that performs positioning.

[0017] Each of the multiple base stations includes a base station positioning unit, a determination unit, a base station compressed message generation unit, and a base station communication unit. The base station positioning unit calculates the position of the base station using the received positioning signal. The determination unit determines the true navigation message by checking whether the calculated base station position is the same as the pre-stored position of the base station. The base station compressed message generation unit compresses the true navigation message to generate a base station compressed message. The base station communication unit transmits the true / false determination result and the base station compressed message.

[0018] The management base station includes a communication unit and a message determination unit. The management base station communication unit transmits and receives the true / false determination result, the base station compressed message, and the transmitting base station compressed message. The message determination unit compares the multiple base station compressed messages and determines the transmitting base station compressed message.

[0019] The positioning device includes a device communication unit, a verification compressed message generation unit, a determination unit, and a positioning unit. The device communication unit receives a transmitting base station compressed message. The verification compressed message generation unit compresses the navigation message of the received positioning signal to generate a verification compressed message. The determination unit compares the transmitting base station compressed message with the verification compressed message to determine whether the received navigation message is authentic. The positioning unit calculates the position of the positioning device using the positioning signal for which the received navigation message is authentic.

[0020] This configuration allows for easy computational processing to determine authenticity using compressed navigation messages. This allows for high-speed authentication and positioning, and realizes a positioning device with a simple configuration that can reduce costs. Furthermore, since authentication is performed based on multiple navigation messages, the reliability of the authentication is improved.

[0021] A positioning system according to one embodiment of the present invention comprises a plurality of base stations, each of which stores its own time in advance, a management base station that manages the plurality of base stations, and a positioning device that performs positioning.

[0022] Each of the multiple base stations includes a base station time calculation unit, a base station determination unit, a base station compressed message generation unit, and a base station communication unit. The base station time calculation unit calculates the base station time using the received positioning signal. The base station determination unit determines the authenticity of the navigation message using the calculated base station time and the base station's own time stored in advance. The base station compressed message generation unit compresses the true navigation message to generate a base station compressed message. The base station communication unit transmits the authenticity determination result and the base station compressed message.

[0023] The management base station includes a management base station communication unit and a message determination unit. The management base station communication unit transmits and receives the true / false determination result, the base station compressed message, and the transmitting base station compressed message. The message determination unit compares the multiple base station compressed messages and determines the transmitting base station compressed message.

[0024] The positioning device includes a device communication unit, a verification compressed message generation unit, a device determination unit, and a positioning unit. The device communication unit receives a transmitting base station compressed message. The verification compressed message generation unit compresses the navigation message of the received positioning signal to generate a verification compressed message. The device determination unit compares the transmitting base station compressed message with the verification compressed message to determine whether the received navigation message is authentic. The positioning unit calculates the position of the positioning device using the positioning signal for which the received navigation message is authentic.

[0025] This configuration allows for easy computational processing to determine authenticity using compressed navigation messages. This allows for high-speed authentication and positioning, and realizes a positioning device with a simple configuration that can reduce costs. Furthermore, since authentication is performed based on multiple navigation messages, the reliability of the authentication is improved.

[0026] In a positioning system according to an embodiment of the present invention, a base station positioning unit calculates the position and time of the base station using a received positioning signal, and a base station determination unit determines the true navigation message by further using the fact that the calculated base station time is the same as the base station's own time stored in advance.

[0027] In this configuration, both the position coordinates and the time are used, so authenticity can be determined more accurately.

[0028] In the positioning system according to an embodiment of the present invention, the message determination unit determines the base station compressed message having the largest number of identical base station compressed messages as the transmitting base station compressed message.

[0029] In this configuration, the authenticity of the navigation message can be determined through simple processing, and the speed of the authenticity determination process can be increased.

[0030] In the positioning system according to an embodiment of the present invention, the base station compressed message generator generates the base station compressed message by further using a digital signature and a public key issued by the positioning system to which the positioning satellite belongs.

[0031] This configuration further improves the accuracy of authenticity determination at the base station. In this case, the base station needs to be equipped with a high-performance arithmetic processing unit, but the positioning device does not need to be equipped with a high-performance arithmetic processing unit. Therefore, a positioning device with a simple configuration that can be reduced in cost can be realized.

[0032] A positioning system according to an embodiment of the present invention includes a base station and a positioning device that performs positioning.

[0033] The base station includes a positioning signal receiving unit, a key receiving unit, a base station determination unit, a base station compressed message generating unit, and a base station communication unit. The positioning signal receiving unit receives the positioning signal and acquires the digital signature and the navigation message. The key receiving unit receives a public key corresponding to the digital signature. The base station determination unit determines the true navigation message using the digital signature and the public key. The base station compressed message generating unit compresses the true navigation message to generate a base station compressed message. The base station communication unit transmits the base station compressed message.

[0034] The positioning device includes a device communication unit, a verification compressed message generation unit, a device determination unit, and a positioning unit. The device communication unit receives a base station compressed message. The verification compressed message generation unit compresses the navigation message of the received positioning signal to generate a verification compressed message. The device determination unit compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic. The positioning unit calculates the position of the positioning device using the positioning signal for which the received navigation message is authentic.

[0035] In this configuration, the base station uses the digital signature and the public key to determine authenticity. This eliminates the need for a high-performance processing unit in the positioning device. This allows for a simpler configuration and lower costs.

[0036] In a positioning system according to an embodiment of the present invention, a positioning device includes a transfer unit that transfers a compressed verification message corresponding to a navigation message determined to be true to another positioning device, and a determination unit of the other positioning device compares the transferred compressed verification message with a compressed verification message generated by the positioning device itself to determine the authenticity of the received navigation message.

[0037] In this configuration, even if another positioning device is far from the base station and cannot receive the base station compressed message generated by the base station, authenticity can be determined using a verification compressed message from a positioning device that can receive the base station compressed message. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a functional block diagram showing an example of the configuration of a positioning system according to the first embodiment. [Figure 2] FIG. 2 is a flowchart showing an example of the positioning method according to the first embodiment. [Figure 3] FIG. 3 is a functional block diagram illustrating an example of the configuration of a positioning system according to the second embodiment. [Figure 4] FIG. 4 is a flowchart showing an example of a positioning method according to the second embodiment. [Figure 5] FIG. 5 is a functional block diagram showing an example of the configuration of a positioning system according to the third embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of a positioning method according to the third embodiment. [Figure 7] FIG. 7 is a functional block diagram showing an example of the configuration of a positioning system according to the fourth embodiment. [Figure 8]FIG. 8 is a flowchart showing an example of processing by the positioning device in the positioning method according to the fourth embodiment. [Figure 9] FIG. 9 is a functional block diagram showing an example of the configuration of a positioning system according to the fifth embodiment. [Figure 10] FIG. 10 is a flowchart showing an example of a positioning method according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0039] [First embodiment] A positioning system and a positioning method according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a functional block diagram showing an example of the configuration of the positioning system according to the first embodiment.

[0040] As shown in Fig. 1, the positioning system 10 includes a base station 20 and a positioning device 30. The base station 20 is stationary and stores its own position coordinates in advance. The positioning device 30 is mobile and uses positioning signals to locate its own device.

[0041] (positioning satellite) The positioning satellites SATA, SATB, SATC, and SATD are positioning satellites of the Global Navigation Satellite System (GNSS). For example, the positioning satellites SATA, SATB, SATC, and SATD are positioning satellites of the Global Positioning System (GPS).

[0042] The positioning satellite SATA broadcasts a positioning signal SSA, which includes a navigation message NAVA specific to the positioning satellite SATA.

[0043] The positioning satellite SATB broadcasts a positioning signal SSB, which includes a navigation message NAVB specific to the positioning satellite SATB.

[0044] The positioning satellite SATC broadcasts a positioning signal SSC, which includes a navigation message NAVC specific to the positioning satellite SATC.

[0045] The positioning satellite SATD broadcasts a positioning signal SSD, which includes a navigation message NAVD specific to the positioning satellite SATD.

[0046] (Base station 20) Base station 20 includes antenna 200, positioning unit 21, determination unit 22, base station compressed message generation unit 23, and communication unit 24. Positioning unit 21, determination unit 22, base station compressed message generation unit 23, and communication unit 24 are configured by, for example, an electronic circuit, a computer, or other arithmetic processing device. Positioning unit 21 corresponds to the "base station positioning unit," determination unit 22 corresponds to the "base station determination unit," and communication unit 24 corresponds to the "base station communication unit."

[0047] The antenna 200 receives the positioning signal SSA broadcast from the positioning satellite SATA, the positioning signal SSB broadcast from the positioning satellite SATB, the positioning signal SSC broadcast from the positioning satellite SATC, and the positioning signal SSD broadcast from the positioning satellite SATD.

[0048] Although FIG. 1 shows a state in which positioning signals are received from four positioning satellites, it is sufficient that positioning signals are received from at least four or more positioning satellites.

[0049] The antenna 200 outputs the received positioning signals SSA, SSB, SSC, and SSD to the positioning unit 21.

[0050] The positioning unit 21 acquires and tracks each of the positioning signals SSA, SSB, SSC, and SSD. By acquiring and tracking, the positioning unit 21 calculates code pseudoranges between the base station 20 (antenna 200) and the positioning satellites SATA, SATB, SATC, and SATD.

[0051] The positioning unit 21 demodulates the navigation messages NAVA, NAVB, NAVC, and NAVD by acquisition and tracking. The positioning unit 21 acquires satellite orbit information of the multiple positioning satellites SATA, SATB, SATC, and SATD from the demodulated navigation messages NAVA, NAVB, NAVC, and NAVD. The positioning unit 21 calculates the position coordinates of the multiple positioning satellites SATA, SATB, SATC, and SATD from the satellite orbit information of the multiple positioning satellites SATA, SATB, SATC, and SATD.

[0052] The positioning unit 21 calculates the position coordinates of the base station 20 using the code pseudoranges between the multiple positioning satellites SATA, SATB, SATC, SATD and the base station 20 (antenna 200) and the position coordinates of the multiple positioning satellites SATA, SATB, SATC, SATD based on the satellite orbit information of the multiple positioning satellites SATA, SATB, SATC, SATD.

[0053] The positioning unit 21 outputs the calculated position coordinates of the base station 20 to the determination unit 22.

[0054] The determination unit 22 compares the calculated position coordinates of the base station 20 (the calculated position coordinates of the base station) with the pre-stored position coordinates of the base station (known position coordinates). If the error between the calculated position coordinates of the base station and the known position coordinates is small, the determination unit 22 determines that the positioning signal used for the calculated position coordinates of the base station is a true positioning signal, and that the navigation message included in this positioning signal is a true navigation message.

[0055] For example, the determination unit 22 sets a threshold for determining authenticity based on a positioning error. The threshold for determining authenticity can be set based on, for example, DOP, etc. If the three-dimensional distance difference between the calculated position coordinates of the base station 20 and the known position coordinates is less than the threshold for determining authenticity, the determination unit 22 determines that the positioning signal used for the calculated position coordinates of the base station 20 is a true positioning signal, and that the navigation message included in this positioning signal is a true navigation message.

[0056] On the other hand, if the three-dimensional distance difference between the base station's calculated position coordinates and the known position coordinates is greater than or equal to the threshold for determining whether the position coordinates are true or false, the judgment unit 22 judges that at least one of the positioning signals used to calculate the base station's position coordinates is a false positioning signal, and that the navigation message included in this positioning signal is a false navigation message.

[0057] Here, a false navigation message is, for example, a navigation message in which satellite orbital information or the like has been intentionally manipulated by someone with malicious intent to obtain position coordinates different from the original position coordinates (true position coordinates). Therefore, if positioning is performed using a false positioning signal containing a false navigation message, the three-dimensional distance difference between the calculated position coordinates of the ground station and the known position coordinates will become large.

[0058] By utilizing this feature, the determination unit 22 can determine with high accuracy whether the navigation message is genuine or false.

[0059] If the determination unit 22 determines that a false navigation message is included, it notifies the positioning unit 21. Based on this notification, the positioning unit 21 changes the combination of positioning signals and calculates the position coordinates of the base station 20. Then, the determination unit 22 determines whether the new combination of positioning signals is a true navigation message or a false navigation message.

[0060] The position coordinates of the base station 20 may be calculated for each combination of a plurality of positioning signals (for example, five or more positioning signals) received in advance by the positioning unit 21. In this case, the determination unit 22 determines whether each combination is a true navigation message or a false navigation message.

[0061] The determination unit 22 may determine whether the navigation message is authentic or not using not only the position coordinates but also the time.

[0062] Specifically, the determination unit 22 compares the time of the base station 20 calculated during positioning with the time of its own station (base station 20) that has been stored in advance. If the calculated time and the pre-stored time are the same or the difference between the calculated time and the pre-stored time is within a predetermined error range, the determination unit 22 determines that the navigation message is genuine. On the other hand, if the difference between the calculated time and the pre-stored time is greater than the predetermined error range, the determination unit 22 determines that the navigation message is false.

[0063] Then, the determination unit 22 determines the navigation message that has been determined to be a true navigation message based on the position coordinates and the time as a true navigation message as the final true navigation message.

[0064] In this case, the case where both the position coordinate and the time are used has been shown, but the true navigation message can also be determined using only the position coordinate or only the time. When only the time is used, the positioning unit 21 corresponds to the "base station time calculation unit" of the present invention.

[0065] The determination unit 22 outputs the true navigation message to the base station compressed message generation unit 23 .

[0066] Alternatively, the determination unit 22 outputs the unique ID of the positioning satellite corresponding to the true navigation message to the base station compressed message generation unit 23. The base station compressed message generation unit 23 acquires the true navigation message from the positioning unit 21 based on the unique ID.

[0067] The base station compressed message generator 23 compresses the true navigation message to generate a base station compressed message. The base station compressed message is composed of data obtained by extracting a portion of the true navigation message. For example, the base station compressed message is composed of data obtained by extracting satellite orbit information (ephemeris information) from the true navigation message.

[0068] The base station compressed message generator 23 generates a base station compressed message for each of the plurality of navigation messages that are determined to be true.

[0069] The base station compressed message generation unit 23 outputs the base station compressed message to the communication unit 24. The communication unit 24 transmits the base station compressed message to the communication unit 32 of the positioning device 30.

[0070] (Positioning device 30) The positioning device 30 includes an antenna 300, a verification compressed message generation unit 31, a communication unit 32, a determination unit 33, and a positioning unit 34. The verification compressed message generation unit 31, the communication unit 32, the determination unit 33, and the positioning unit 34 are configured by, for example, an electronic circuit, a processing device such as a computer, etc. The communication unit 32 corresponds to the "device communication unit," and the determination unit 33 corresponds to the "device determination unit."

[0071] The antenna 300 receives the positioning signal SSA broadcast from the positioning satellite SATA, the positioning signal SSB broadcast from the positioning satellite SATB, the positioning signal SSC broadcast from the positioning satellite SATC, and the positioning signal SSD broadcast from the positioning satellite SATD.

[0072] The antenna 300 outputs the received positioning signals SSA, SSB, SSC, and SSD to the verification compressed message generator 31 and the positioning unit .

[0073] The verification compressed message generator 31 demodulates the navigation messages NAVA, NAVB, NAVC, and NAVD from the multiple positioning signals SSA, SSB, SSC, and SSD, respectively. The verification compressed message generator 31 compresses the navigation messages NAVA, NAVB, NAVC, and NAVD to generate verification compressed messages corresponding to each navigation message. The method for generating the verification compressed messages in the verification compressed message generator 31 is the same as the method for generating base station compressed messages in the base station compressed message generator 23.

[0074] The verification compressed message generator 31 outputs the generated verification compressed message to the decision unit 33 .

[0075] The communication unit 32 receives the base station compressed message from the communication unit 24 of the base station 20. The communication unit 32 outputs the base station compressed message to the determination unit 33.

[0076] The determination unit 33 compares the base station compressed message with the verification compressed message.

[0077] If there is a compressed verification message having the same data structure as the base station compressed message, the determining unit 33 determines that the navigation message from which this compressed verification message originates is the true navigation message.

[0078] If there is no base station compressed message having the same data structure as the verification compressed message, the determining unit 33 determines that the navigation message from which this verification compressed message originates is a fake navigation message.

[0079] At this time, the determination unit 33 performs this determination for each navigation message, in other words, for each positioning signal or each positioning satellite. That is, the determination unit 33 selects a verification compressed message and a base station compressed message based on the unique ID of the positioning satellite. The determination unit 33 determines the authenticity of the navigation message using the selected verification compressed message and base station compressed message.

[0080] The determination unit 33 outputs the result of determining whether the navigation message is true or false to the positioning unit 34 .

[0081] The positioning unit 34 calculates the position coordinates of the positioning device 30 (measures the position of the positioning device 30) based on the result of determining whether the navigation message is true or false. More specifically, the positioning unit 34 calculates the position coordinates of the positioning device 30 (measures the position of the positioning device 30) using the original positioning signal of the true navigation message.

[0082] With this configuration, the positioning device 30 can perform positioning using only true positioning signals, suppressing the use of false positioning signals, thereby enabling the positioning device 30 to achieve highly accurate positioning.

[0083] Furthermore, the positioning device 30 can determine the authenticity of the navigation message and the positioning signal through simple calculations using the compressed navigation message, which enables the positioning device 30 to perform authenticity determination and positioning at high speed, and achieves a simple configuration that allows for low cost.

[0084] (Positioning method) Fig. 2 is a flowchart showing an example of a positioning method according to the first embodiment. Specific details of each process in Fig. 2 have been described in the above-mentioned configuration section, and explanations will be omitted except for sections that require additional explanation. Furthermore, in the explanation using Fig. 2, the base station 20 and the positioning device 30 will be used as the subject, but each process is executed by each functional unit as shown in the above-mentioned configuration explanation.

[0085] The base station 20 calculates the position coordinates of the base station 20 (locates the position of the base station 20) using positioning signals SSA, SSB, SSC, and SSD broadcast from a plurality of positioning satellites SATA, SATB, SATC, and SATD (S21).

[0086] The base station 20 determines whether the navigation message is true or false using the positioning result (calculated position coordinates) (S22). More specifically, the base station 20 determines whether the navigation message is true or false using the error between the position coordinates of the base station stored in advance and the positioning result (calculated position coordinates).

[0087] The base station 20 generates a base station compressed message using the true navigation message (S23).

[0088] The base station 20 transmits the base station compressed message to the positioning device 30 (S24).

[0089] The positioning device 30 demodulates navigation messages from positioning signals SSA, SSB, SSC, and SSD broadcast from a plurality of positioning satellites SATA, SATB, SATC, and SATD to generate compressed verification messages (S31).

[0090] The positioning device 30 receives the base station compressed message (S32). Note that the order of steps S31 and S32 is not limited to this.

[0091] The positioning device 30 compares the verification compressed message with the base station compressed message to determine whether the navigation message is authentic (S33). More specifically, the positioning device 30 compares the verification compressed message with the base station compressed message for each demodulated navigation message. If the verification compressed message and the base station compressed message have the same data structure (match), the positioning device 30 determines that the navigation message that is the source of this verification compressed message is the true navigation message. On the other hand, if the verification compressed message and the base station compressed message do not have the same data structure (do not match), the positioning device 30 determines that the navigation message that is the source of this verification compressed message is a fake navigation message.

[0092] The positioning device 30 calculates the position coordinates of the positioning device 30 (locates the position of the positioning device 30) using the true navigation message and its positioning signal (S34).

[0093] [Second embodiment] A positioning system and a positioning method according to a second embodiment of the present invention will be described with reference to the drawing. Fig. 3 is a functional block diagram showing an example of the configuration of the positioning system according to the second embodiment.

[0094] 3, the positioning system 10A according to the second embodiment differs from the positioning system 10 according to the first embodiment in that it includes a plurality of base stations (base station 20X1, base station 20X2, base station 20X3), that it includes a management base station 40, and that the positioning device 30 determines the authenticity of the navigation message based on information from the management base station 40. Other configurations of the positioning system 10A are the same as those of the positioning system 10, and a description of similar parts will be omitted.

[0095] The positioning system 10A includes a plurality of base stations (base station 20X1, base station 20X2, base station 20X3), a positioning device 30, and a management base station 40. The number of base stations is not limited to three, and may be any number as long as it is plural.

[0096] The base stations 20X1, 20X2, and 20X3 have the same configuration as the base station 20 according to the first embodiment. The base stations 20X1, 20X2, and 20X3 each perform authenticity determination for each navigation message (for each positioning signal and for each positioning satellite). The base stations 20X1, 20X2, and 20X3 transmit their authenticity determination results and the base station compressed messages determined to be authentic to the management base station 40.

[0097] The management base station 40 includes a communication unit 41 and a message determination unit 42. The communication unit 41 receives the authenticity determination results and the base station compressed messages determined to be authentic from the base stations 20X1, 20X2, and 20X3. The communication unit 41 outputs the authenticity determination results to the message determination unit 42.

[0098] The message determination unit 42 performs authenticity determination as a preliminary preparation for transmission to the positioning device 30, based on authenticity determination results determined by multiple base stations for one navigation message (positioning signal, positioning satellite). More specifically, if the majority of determinations are true for one navigation message (positioning signal, positioning satellite), the message determination unit 42 determines that this navigation message is a true navigation message. On the other hand, if the majority of determinations are false for one navigation message (positioning signal, positioning satellite), the message determination unit 42 determines that this navigation message is a false navigation message.

[0099] The message determination unit 42 determines the base station compressed message of the navigation message that has been determined to be the true navigation message as the transmitting base station compressed message.

[0100] The communication unit 41 transmits the compressed transmitting base station message determined by the message determination unit 42 to the positioning device 30 .

[0101] The positioning device 30 uses the transmitting base station compressed message to determine the authenticity of the navigation message of the received positioning signal and perform positioning, similar to the first embodiment.

[0102] With this configuration, the positioning system 10A refers to the determination results of a plurality of base stations, thereby improving the reliability of determining whether the navigation message is authentic.

[0103] Furthermore, the positioning system 10A uses majority voting for authenticity determination, which allows the positioning system 10A to easily determine the authenticity of the navigation message, thereby enabling faster authenticity determination processing.

[0104] In the above configuration, the plurality of base stations are separate from the management base station 40. However, at least one of the plurality of base stations may be provided with the functions of the management base station 40.

[0105] Furthermore, in the positioning system 10A, an example has been shown in which majority voting is used, but it is also possible to transmit to the positioning device 30 a base station compressed message of a navigation message that has been determined to be true by all base stations.

[0106] (Positioning method) 4 is a flowchart showing an example of the positioning method according to the second embodiment. In the positioning method according to the second embodiment, the basic processes of the base stations 20X1, 20X2, and 20X3 and the basic processes of the positioning device 30 are the same as those in the positioning method according to the first embodiment, and therefore, a description of the same parts will be omitted.

[0107] The base stations 20X1, 20X2, and 20X3 transmit the authenticity determination results and the compressed base station messages to the management base station 40 (S24A).

[0108] The management base station 40 receives the authenticity determination result and the base station compressed message (S41).

[0109] The management base station 40 determines a transmitting base station compressed message from the plurality of base station compressed messages based on the plurality of true / false judgment results (S42).

[0110] The management base station 40 transmits the transmitting base station compressed message to the positioning device 30 (S43).

[0111] The positioning device 30 receives the compressed transmitting base station message (S32A) and determines whether the navigation message is authentic or not using the compressed transmitting base station message (S33A).

[0112] [Third embodiment] A positioning system and a positioning method according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 5 is a functional block diagram showing an example of the configuration of the positioning system according to the third embodiment.

[0113] 5, the positioning system 10B according to the third embodiment differs from the positioning system 10 according to the first embodiment in that it also uses a digital signature and a key (public key) to verify the authenticity of the navigation message. The other configurations of the positioning system 10B are the same as those of the positioning system 10, and a description of the same parts will be omitted.

[0114] The positioning system 10B includes a base station 20B, a positioning device 30, and a positioning system management station 50.

[0115] The positioning system management station 50 includes a digital signature issuing unit 51, a key issuing unit 52, a digital signature transmitting unit 53, and a key transmitting unit .

[0116] The digital signature issuing unit 51 issues a digital signature of the positioning system 10C to which the positioning satellites SATA, SATB, SATC, and SATD belong. The key issuing unit 52 issues a key (public key) corresponding to the digital signature issued by the digital signature issuing unit 51.

[0117] The digital signature transmission unit 53 transmits the digital signature to a plurality of positioning satellites SATA, SATB, SATC, and SATD.

[0118] Multiple positioning satellites SATA, SATB, SATC, and SATD broadcast positioning signals SSA, SSB, SSC, and SSD, respectively, which contain digital signatures along with navigation messages.

[0119] The key sending unit 54 sends the key to the base station 20B.

[0120] The base station 20B includes a key receiving unit 25. The key receiving unit 25 receives a key and outputs it to the determining unit 22B.

[0121] The determination unit 22B unlocks the digital signature included in the positioning signal with a key and checks the contents of the digital signature to determine whether the navigation message is authentic or not.

[0122] The determination unit 22B makes a final determination of the authenticity of the navigation message based on the determination of authenticity based on the position coordinates as shown in the first embodiment and the determination of authenticity based on the combination of the digital signature and the key.

[0123] Specifically, the determination unit 22B determines that the navigation message is genuine when the determination based on the position coordinates is true and the determination based on the combination of the electronic signature and the key is true. On the other hand, the determination unit 22B determines that the navigation message is fake when either the determination based on the position coordinates or the determination based on the combination of the electronic signature and the key is false.

[0124] With this configuration, the base station 20B can further improve the accuracy of determining whether the navigation message is authentic or not.

[0125] In this configuration, the base station 20B needs to be equipped with a high-performance arithmetic processing device, but the positioning device 30 does not need to be equipped with a high-performance arithmetic processing device. Therefore, it is possible to realize a positioning device 30 with a simple configuration that allows for cost reduction.

[0126] (Positioning method) 6 is a flowchart showing an example of a positioning method according to the third embodiment. Only differences between the positioning method according to the third embodiment and the positioning method according to the first embodiment will be described below, and descriptions of similar parts will be omitted.

[0127] The base station 20B determines whether the navigation message is genuine by using the result of comparing the digital signature with the key and the positioning result (S22B).

[0128] More specifically, the base station 20B receives and stores the key. The base station 20B demodulates the digital signature from the received positioning signal. The base station 20B unlocks the digital signature with the key and verifies the contents of the digital signature to determine the authenticity of the navigation message.

[0129] The base station 20B compares the position coordinates determined by the positioning signal with the position of the base station stored in advance to determine the authenticity of the navigation message. At this time, the base station 20B may perform the authenticity determination based on the position coordinates using only the positioning signal that has been determined to be a genuine navigation message in the determination using the digital signature and key.

[0130] [Fourth embodiment] A positioning system and a positioning method according to a fourth embodiment of the present invention will be described with reference to the drawings. Fig. 7 is a functional block diagram showing an example of the configuration of the positioning system according to the fourth embodiment.

[0131] 7, the positioning system 10C according to the fourth embodiment differs from the positioning system 10 according to the first embodiment in that it includes a plurality of positioning devices 30C1 and 30C2 and that the positioning device 30C2 cannot communicate directly with the base station 20. Other configurations of the positioning system 10C are similar to those of the positioning system 10, and therefore a description of similar parts will be omitted.

[0132] The positioning system 10C includes a base station 20, a positioning device 30C1, and a positioning device 30C2. The number of positioning devices is not limited to two, but may be any number.

[0133] The positioning device 30C1 and the positioning device 30C2 basically have the same configuration as the positioning device 30 according to the first embodiment, but differ in that they include a communication unit 32C that is capable of mutual communication.

[0134] 7, positioning device 30C1 can communicate directly with base station 20. On the other hand, positioning device 30C2 cannot communicate directly with base station 20, but can communicate directly with positioning device 30C1. Note that "cannot communicate directly" here does not only mean that the distance from base station 20 to positioning device 30C2 is too long for communication radio waves to reach them, but also means that the communication specifications of positioning device 30C2 are different from those of base station 20.

[0135] Like the positioning device 30 according to the first embodiment, the positioning device 30C1 uses the base station compressed message received from the base station 20 to determine the authenticity of the navigation message of the positioning signal received by the positioning device 30C1.

[0136] When the positioning device 30C2 detects that it cannot receive the base station compressed message, it sends a transfer request to the positioning device 30C1 with which it can communicate via the respective communication units 32C.

[0137] Upon receiving the transfer request, the positioning device 30C1 transfers the compressed verification message that has been determined to be a genuine navigation message to the positioning device 30C2 via the respective communication units 32C.

[0138] The positioning device 30C2 determines the authenticity of the navigation message of the positioning signal received by the positioning device 30C2 using the verification compressed message determined to be the authentic navigation message by the positioning device 30C1.

[0139] Note that positioning device 30C1 may transfer the base station compressed message to positioning device 30C2.

[0140] With this configuration, even if the positioning device 30C2 cannot directly receive the base station compressed message from the base station 20, it can suppress the use of false positioning signals and perform positioning using only true positioning signals. Therefore, the positioning device 30C2 can achieve highly accurate positioning.

[0141] (Positioning method) FIG. 8 is a flowchart showing an example of processing by the positioning device in the positioning method according to the fourth embodiment.

[0142] The positioning devices 30C1 and 30C2 demodulate navigation messages from positioning signals SSA, SSB, SSC, and SSD broadcast from a plurality of positioning satellites SATA, SATB, SATC, and SATD to generate compressed verification messages (S31).

[0143] If the positioning device 30C1 can receive the base station compressed message (S32: YES), it compares the verification compressed message with the base station compressed message to determine whether the navigation message is authentic (S33).

[0144] If the positioning device 30C2 cannot receive the base station compressed message (S32: NO), it requests the other positioning device 30C1 to transfer the message. The positioning device 30C2 receives the verification compressed message that has been determined to be true and transferred from the other positioning device 30C1 (S35). The positioning device 30C2 determines the authenticity of the navigation message using the transferred verification compressed message (S36).

[0145] The positioning devices 30C1 and 30C2 use the true navigation message and its positioning signal to determine the position coordinates of the positioning devices 30C1 and 30C2, respectively (S34).

[0146] [Fifth embodiment] A positioning system and a positioning method according to a fifth embodiment of the present invention will be described with reference to the drawing. Fig. 9 is a functional block diagram showing an example of the configuration of the positioning system according to the fifth embodiment.

[0147] 9, the positioning system 10D according to the fifth embodiment differs from the positioning system 10B according to the third embodiment in that the positioning system 10D determines the authenticity of the navigation message using only a digital signature and a key (public key). The other configurations of the positioning system 10D are the same as those of the positioning system 10B, and a description of the same parts will be omitted.

[0148] The positioning system 10D includes a base station 20D, a positioning device 30, and a positioning system management station 50.

[0149] The base station 20D includes a positioning signal receiving unit 21D and a determining unit 22D.

[0150] The positioning signal receiving unit 21D receives the positioning signal and acquires the digital signature and the navigation message.

[0151] The key receiving unit 25 of the base station 20D receives the key (public key) and outputs it to the determining unit 22D.

[0152] The determination unit 22D unlocks the digital signature included in the positioning signal with a key and checks the contents of the digital signature to determine whether the navigation message is authentic or not.

[0153] The base station compressed message generator 23 generates a base station compressed message from the true navigation message determined by the determination unit 22D using only the digital signature and key.

[0154] In this configuration, the base station 20D needs to be equipped with a high-performance arithmetic processing unit, but the positioning device 30 does not need to be equipped with a high-performance arithmetic processing unit. Therefore, it is possible to realize a positioning device 30 with a simple configuration that allows for cost reduction.

[0155] (Positioning method) 10 is a flowchart showing an example of a positioning method according to the fifth embodiment. Only differences between the positioning method according to the fifth embodiment and the positioning method according to the third embodiment will be described below, and descriptions of similar parts will be omitted.

[0156] The base station 20D determines the authenticity of the navigation message by using the result of comparing the digital signature with the key (S22D).

[0157] The configurations and methods of the above-described embodiments can be combined as appropriate, and effects according to each combination can be achieved.

[0158] <1> a base station that stores its own position in advance; a positioning device for performing positioning; Equipped with The base station a base station positioning unit that calculates the position of the base station using the received positioning signal; a base station determination unit that determines a true navigation message by determining whether the calculated position of the base station is the same as the pre-stored position of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the base station compressed message; Equipped with The positioning device is a device communication unit for receiving the base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

[0159] <2> a base station that stores its own time in advance; a positioning device for performing positioning; Equipped with The base station a base station time calculation unit that calculates the time of the base station using the received positioning signal; a base station determination unit that determines a true navigation message by determining whether the calculated time of the base station is the same as the pre-stored time of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the base station compressed message; Equipped with The positioning device is a device communication unit for receiving the base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

[0160] <3> <1> The positioning system according to claim 1, the base station positioning unit calculates the position and time of the base station using the received positioning signal; The base station determination unit determines a true navigation message by further using the fact that the calculated time of the base station and the pre-stored time of the base station are the same.

[0161] <4> a plurality of base stations each storing its own position in advance; a management base station that manages a plurality of base stations; a positioning device for performing positioning; Equipped with The plurality of base stations a base station positioning unit that calculates the position of the base station using the received positioning signal; a base station determination unit that determines whether a navigation message is authentic or not using the calculated position of the base station and the pre-stored position of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the determination result of the authenticity and the base station compressed message; Each one is equipped with The management base station a management base station communication unit that transmits and receives the determination result, the base station compressed message, and a transmitting base station compressed message; a message determination unit that compares the plurality of base station compressed messages and determines the transmitting base station compressed message; The positioning device is a device communication unit for receiving the transmitting base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the transmitting base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates a position of the positioning device using a positioning signal in which the received navigation message is true; A positioning system comprising:

[0162] <5> a plurality of base stations each storing its own time in advance; a management base station that manages a plurality of base stations; a positioning device for performing positioning; Equipped with The plurality of base stations a base station time calculation unit that calculates the time of the base station using the received positioning signal; a base station determination unit that determines authenticity of a navigation message using the calculated time of the base station and the pre-stored time of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the determination result of the authenticity and the base station compressed message; Each one is equipped with The management base station a management base station communication unit that transmits and receives the determination result, the base station compressed message, and a transmitting base station compressed message; a message determination unit that compares the plurality of base station compressed messages and determines the transmitting base station compressed message; The positioning device is a device communication unit for receiving the transmitting base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the transmitting base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

[0163] <6> <4> The positioning system according to claim 1, the base station positioning unit calculates the position and time of the base station using the received positioning signal; The base station determination unit determines a true navigation message by further using the fact that the calculated time of the base station and the pre-stored time of the base station are the same.

[0164] <7> <4> or <6> The positioning system according to claim 1, The message determination unit determines the base station compressed message having the largest number of identical base station compressed messages as the transmitting base station compressed message.

[0165] <8> <1> , <4> ~ <7> The positioning system according to any one of the preceding claims, A positioning system, wherein the base station compressed message generation unit generates the base station compressed message by further using an electronic signature and a public key issued by a positioning system to which the positioning satellite belongs.

[0166] <9> <2> The positioning system according to claim 1, A positioning system, wherein the base station compressed message generation unit generates the base station compressed message by further using an electronic signature and a public key issued by a positioning system to which the positioning satellite belongs.

[0167] <10> <3> The positioning system according to claim 1, A positioning system, wherein the base station compressed message generation unit generates the base station compressed message by further using an electronic signature and a public key issued by a positioning system to which the positioning satellite belongs.

[0168] <11> A base station; a positioning device for performing positioning; Equipped with The base station a positioning signal receiving unit that receives a positioning signal and acquires an electronic signature and a navigation message; a key receiving unit for receiving a public key corresponding to the digital signature; a base station determination unit that determines a true navigation message using the digital signature and the public key; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the base station compressed message; Equipped with The positioning device is a device communication unit for receiving the base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

[0169] <12> <1> ~ <11> The positioning system according to any one of the preceding claims, The positioning device is a transfer unit that transfers a verification compressed message corresponding to the navigation message determined to be true to another positioning device; the device determination unit of the other positioning device compares the transferred compressed verification message with a compressed verification message generated by its own device to determine whether the received navigation message is authentic or not; Positioning system. [Explanation of symbols]

[0170] 10, 10A, 10B, 10C, 10D: Positioning system 20, 20B, 20D, 20X1, 20X2, 20X3: Base station 21: Positioning unit 21D: Positioning signal receiver 22, 22B, 22D: Judgment section 23: Base station compressed message generator 24: Communications Department 25: Key receiver 30, 30C1, 30C2: Positioning device 31: Verification compressed message generator 32, 32C: Communication Department 33: Judgment section 34: Positioning unit 40: Management base station 41: Communications Department 42: Message determination section 50: Positioning System Management Station 51: Electronic Signature Issuance Department 52: Key Issuance Department 53: Electronic signature sending unit 54: Key transmission unit 200: Antenna 300: Antenna NAVA, NAVB, NAVC, NAVD: Navigation messages SATA, SATB, SATC, SATD: Positioning satellites SSA, SSB, SSC, SSD: Positioning signals

Claims

1. a base station that stores its own position in advance; a positioning device for performing positioning; Equipped with The base station a base station positioning unit that calculates the position of the base station using the received positioning signal; a base station determination unit that determines a true navigation message by determining whether the calculated position of the base station is the same as the pre-stored position of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the base station compressed message; Equipped with The positioning device is a device communication unit for receiving the base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

2. a base station that stores its own time in advance; a positioning device for performing positioning; Equipped with The base station a base station time calculation unit that calculates the time of the base station using the received positioning signal; a base station determination unit that determines a true navigation message by determining whether the calculated time of the base station is the same as the pre-stored time of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the base station compressed message; Equipped with The positioning device is a device communication unit for receiving the base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

3. 2. The positioning system of claim 1, the base station positioning unit calculates the position and time of the base station using the received positioning signal; the base station determination unit determines a true navigation message by further using the fact that the calculated time of the base station and the pre-stored time of the base station are the same. Positioning system.

4. a plurality of base stations each storing its own position in advance; a management base station that manages a plurality of base stations; a positioning device for performing positioning; Equipped with The plurality of base stations a base station positioning unit that calculates the position of the base station using the received positioning signal; a base station determination unit that determines whether a navigation message is authentic or not using the calculated position of the base station and the pre-stored position of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the determination result of the authenticity and the base station compressed message; Each one is equipped with The management base station a management base station communication unit that transmits and receives the determination result, the base station compressed message, and a transmitting base station compressed message; a message determination unit that compares the plurality of base station compressed messages and determines the transmitting base station compressed message; The positioning device is a device communication unit for receiving the transmitting base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the transmitting base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates a position of the positioning device using a positioning signal in which the received navigation message is true; A positioning system comprising:

5. a plurality of base stations each storing its own time in advance; a management base station that manages a plurality of base stations; a positioning device for performing positioning; Equipped with The plurality of base stations a base station time calculation unit that calculates the time of the base station using the received positioning signal; a base station determination unit that determines authenticity of a navigation message using the calculated time of the base station and the pre-stored time of the base station; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the determination result of the authenticity and the base station compressed message; Each one is equipped with The management base station a management base station communication unit that transmits and receives the determination result, the base station compressed message, and a transmitting base station compressed message; a message determination unit that compares the plurality of base station compressed messages and determines the transmitting base station compressed message; The positioning device is a device communication unit for receiving the transmitting base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the transmitting base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

6. 5. The positioning system according to claim 4, the base station positioning unit calculates the position and time of the base station using the received positioning signal; the base station determination unit determines a true navigation message by further using the fact that the calculated time of the base station and the pre-stored time of the base station are the same. Positioning system.

7. 5. The positioning system according to claim 4, the message determination unit determines the base station compressed message having the largest number of identical base station compressed messages as the transmitting base station compressed message; Positioning system.

8. 2. The positioning system of claim 1, the base station compressed message generation unit further uses an electronic signature and a public key issued by a positioning system to which the positioning satellite belongs to generate the base station compressed message; Positioning system.

9. 3. The positioning system according to claim 2, the base station compressed message generation unit further uses an electronic signature and a public key issued by a positioning system to which the positioning satellite belongs to generate the base station compressed message; Positioning system.

10. 4. The positioning system according to claim 3, the base station compressed message generation unit further uses an electronic signature and a public key issued by a positioning system to which the positioning satellite belongs to generate the base station compressed message; Positioning system.

11. A base station; a positioning device for performing positioning; Equipped with The base station a positioning signal receiving unit that receives a positioning signal and acquires an electronic signature and a navigation message; a key receiving unit for receiving a public key corresponding to the digital signature; a base station determination unit that determines a true navigation message using the digital signature and the public key; a base station compressed message generator that compresses the true navigation message to generate a base station compressed message; a base station communication unit that transmits the base station compressed message; Equipped with The positioning device is a device communication unit for receiving the base station compressed message; a verification compressed message generator that compresses the navigation message of the received positioning signal to generate a verification compressed message; an apparatus determination unit that compares the base station compressed message with the verification compressed message to determine whether the received navigation message is authentic; a positioning unit that calculates the position of the positioning device using a positioning signal for which the received navigation message is true; A positioning system comprising:

12. 2. The positioning system of claim 1, The positioning device is a transfer unit that transfers a verification compressed message corresponding to the navigation message determined to be true to another positioning device; the device determination unit of the other positioning device compares the transferred compressed verification message with a compressed verification message generated by its own device to determine whether the received navigation message is authentic or not; Positioning system.

13. Using the positioning signal, the position of the base station that has stored the position of the base station in advance is calculated, determining a true navigation message based on whether the calculated position of the base station is the same as the pre-stored position of the own station; compressing the true navigation message to generate a base station compressed message; transmitting the base station compressed message; compressing the navigation message of the received positioning signal to generate a verification compressed message; comparing the base station compressed message with the verification compressed message to determine the authenticity of the received navigation message; Calculating the position of the positioning device using the positioning signal for which the received navigation message is true; Positioning method.

14. Using the positioning signal received by the base station, the position of the base station that has its own position stored in advance is calculated; determining a true navigation message based on whether the calculated position of the base station is the same as the pre-stored position of the own station; compressing the true navigation message to generate a base station compressed message; transmitting the base station compressed message; compressing the navigation message of the positioning signal received by a positioning device to generate a verification compressed message; comparing the base station compressed message with the verification compressed message to determine the authenticity of the received navigation message; Calculating the position of the positioning device using the positioning signal for which the received navigation message is true; Positioning method.

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