WO2026028501A1

WO2026028501A1 - Positioning system and positioning method

Info

Publication number: WO2026028501A1
Application number: PCT/JP2025/006831
Authority: WO
Inventors: Takaki Tominaga; Toshihiro Yanai
Original assignee: Furuno Electric Co Ltd
Current assignee: Furuno Electric Co Ltd
Priority date: 2024-07-31
Filing date: 2025-02-27
Publication date: 2026-02-05
Anticipated expiration: 2027-01-31
Also published as: JP2026022692A

Abstract

Various apparatuses for providing a positioning method are disclosed. The method includes calculating a position of a base station using a received positioning signal. The method also includes determining a true navigation message using a condition. Herein, the calculated position of the base station is approximate to a pre-stored position information of the base station. The method includes compressing the true navigation message to generate a base station compression message. The method also includes transmitting the base station compression message. The method includes compressing a received navigation message of the received positioning signal to generate a verification compression message. The method also includes verifying the base station compression message with the verification compression message to determine an authenticity of the received navigation message. The method further includes calculating the position of a positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.

Description

POSITIONING SYSTEM AND POSITIONING METHOD

The present disclosure generally relates to positioning technology and more particularly relates to a positioning system using positioning signals broadcast from Global Navigation Satellite System (GNSS) satellites.

Background

Positioning systems play an important role in modern navigation, geo-location, and authentication technologies. Positioning systems enable accurate determination of location-based data for various applications. Satellite-based navigation systems, in particular, rely on positioning signals to provide real-time location information.

A Japanese patent document, JP 6213258 B2, titled “Position information authentication system, positioning terminal, and position information acquisition device” and a United States patent document, US 20230209352 A1, titled “Authentication methods for a satellite-based navigation system, devices for authenticating messages and authentication system” disclose technologies for verifying the authenticity of positioning signals using electronic signatures and hash values.

However, the use of electronic signatures and hash values in authentication processes imposes a significant computational load. As a result, real-time authentication and positioning require high-performance computing devices, making implementation costly and complex. Furthermore, developing a simplified and cost-effective positioning device capable of performing these operations efficiently remains challenging.

Therefore, a technological need exists to provide an improved positioning device with a simple configuration that can perform authenticity determination and positioning at high speed and reduced costs.

A positioning system according to an embodiment of the present invention includes a positioning system. The positioning system includes a base station storing position information of the base station in advance. Herein, the base station includes base station positioning circuitry configured to calculate a position of the base station using a received positioning signal. The base station also includes base station determination circuitry configured to determine a true navigation message using a condition. Herein, the calculated position of the base station is approximate to the pre-stored position information of the base station. The base station further includes base station compression message generation circuitry configured to compress the true navigation message to generate a base station compression message. The base station also includes base station communication circuitry configured to transmit the base station compression message.

The positioning system also includes a positioning device configured to perform positioning. Herein, the positioning device includes device communication circuitry configured to receive the base station compression message. The positioning device also includes verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message. The positioning device further includes device determination circuitry configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message. The positioning device also includes positioning circuitry configured to calculate the position of the positioning device using the received positioning signal in which the received navigation message is the true navigation message.

In this configuration, the authenticity can be determined by simple arithmetic processing using the compressed navigation message. Thus, the authenticity determination and positioning can be performed at high speed, and a positioning device with a simple configuration can be realized at a low or reduced cost.

A positioning system according to an embodiment of the present invention includes a base station storing time information of the base station in advance. Herein, the base station includes a base station positioning circuitry configured to calculate a time of the base station using a received positioning signal. The base station also includes a base station determination circuitry configured to determine a true navigation message using a condition. Herein, the calculated time of the base station is approximate to the pre-stored time information of the base station. The base station also includes a base station compression message generation circuitry configured to compress the true navigation message to generate a base station compression message. The base station further includes a base station communication circuitry configured to transmit the base station compression message. Further, the positioning system includes a positioning device configured to perform positioning. Herein, the positioning device includes a device communication circuitry configured to receive the base station compression message. Herein, the positioning device also includes a verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message. The positioning device further includes a device determination circuitry configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message. The positioning device also includes a positioning circuitry configured to calculate a position of the positioning device using the received positioning signal in which the received navigation message is the true navigation message.

In this configuration, the authenticity can be determined by simple arithmetic processing using the compressed navigation message. As a result, the authenticity determination and positioning can be performed at high speed, and a positioning device with a simple configuration that can be reduced in cost can be realized.

In the positioning system according to an embodiment of the present invention, the base station positioning circuitry is configured to calculate a time of the base station using the received positioning signal. Further, the base station determination unit is configured to determine the true navigation message using another condition. Herein, the calculated time of the base station is approximate to the pre-stored time information of the base station

In this configuration, since both position coordinates and time are used, authenticity can be more accurately determined.

A positioning system according to an embodiment of the present invention includes a plurality of base stations. Herein, each base station of the plurality of base stations stores position information of the each base station in advance. Herein, the each base station of the plurality of base stations includes base station positioning circuitry configured to calculate a position of the each base station using a received positioning signal. Each base station also includes base station determination circuitry configured to determine an authenticity of a true navigation message using a condition wherein the calculated position of the each base station is approximate to the pre-stored stored position information of the each base station. Each base station further includes base station compression message generation circuitry configured to compress the true navigation message to generate a base station compression message. Each base station also includes base station communication circuitry configured to transmit an authenticity determination result and the base station compression message.

The positioning system also includes a management base station configured to manage the plurality of base stations. Herein, the management base station includes management base station communication circuitry configured to transmit and receive the authenticity determination result, and the base station compression message. The management base station also includes message determination circuitry configured to compare a plurality of base station compression messages to determine the base station compression message for transmission.

The positioning system also includes a positioning device configured to perform positioning. Herein, the positioning device includes device communication circuitry configured to receive the base station compression message. The positioning device also includes verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message. The positioning device further includes device determination circuitry configured to verify the base station compression message with the verification compression message to determine the authenticity of the received navigation message. The positioning device also includes positioning circuitry configured to calculate the position of the positioning device using the received positioning signal in which the received navigation message is the true navigation message.

In this configuration, the authenticity can be determined by simple arithmetic processing using the compressed navigation message. Thus, the authenticity determination and positioning can be performed at high speed, and a positioning device with a simple configuration that can be reduced in cost can be realized. Furthermore, since the authenticity determination is performed based on the plurality of navigation messages, the reliability of the authenticity determination is improved.

A positioning system according to an embodiment of the present invention includes a plurality of base stations. Herein, each base station of the plurality of base stations stores time information of the each base station in advance. Herein, the each base station of the plurality of base stations includes base station positioning circuitry configured to calculate a time of the each base station using a received positioning signal. Each base station also includes base station determination circuitry configured to determine an authenticity of a true navigation message using a condition wherein the calculated time of the each base station is approximate to the pre-stored stored time information of the each base station. Each base station further includes base station compression message generation circuitry configured to compress the true navigation message to generate a base station compression message. Each base station also includes base station communication circuitry configured to transmit an authenticity determination result and the base station compression message.

The positioning system also includes a management base station configured to manage the plurality of base stations. Herein, the management base station includes management base station communication circuitry configured to transmit and receive the authenticity determination result, and the base station compression message. The management station also includes message determination circuitry configured to compare a plurality of base station compression messages to determine the base station compression message for transmission.

The positioning system further includes a positioning device configured to perform positioning. Herein, the positioning device includes device communication circuitry configured to receive the base station compression message. The positioning device also includes verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message. The positioning device further includes device determination circuitry configured to verify the base station compression message with the verification compression message to determine the authenticity of the received navigation message. The positioning device also includes positioning circuitry configured to calculate the position of the positioning device using the received positioning signal in which the received navigation message is the true navigation message.

In this configuration, the authenticity can be determined by simple arithmetic processing using the compressed navigation message. Thus, the authenticity determination and positioning can be performed at high speed, and a positioning device with a simple configuration that can be reduced in cost can be realized. Furthermore, since the authenticity determination is performed based on a plurality of navigation messages, the reliability of the authenticity determination is improved.

In the positioning system according to an embodiment of the present invention, the base station positioning circuitry is further configured to calculate a time of the each base station using the received positioning signal. Further, the base station determination circuitry is configured to determine the true navigation message using another condition. Herein, the calculated position of the each base station is approximate to the pre-stored position information of the each base station.

In this configuration, since both the position coordinates and the time are used, the authenticity determination can be more accurately determined.

In the positioning system according to an embodiment of the present invention, the message determination circuitry is further configured to determine the base station compression message having a largest number of identical base station compression messages as the base station compression message for transmission.

In the positioning system according to an embodiment of the present invention, the message determination circuitry is further configured to determine that the navigation message is a true navigation message if the number of true determinations is large for one navigation message, or to determine that the navigation message is a false navigation message if the number of false determinations is large for one navigation message; as the base station compression message for transmission.

In these configurations, the authenticity of the navigation message can be realized by easy processing, and the processing of authenticity determination can be accelerated.

In the positioning system according to an embodiment of the present invention, the base station compression message generation circuitry is further configured to generate the base station compression message using an electronic signature and a public key issued by the positioning system to which a positioning satellite belongs.

In this configuration, the accuracy of truth determination in the base station is further improved. At this time, the base station needs to be provided with a high-performance arithmetic processing unit, but the positioning device does not need to be provided with a high-performance arithmetic processing unit. Therefore, it is possible to realize a positioning device having a simple configuration that can be reduced in cost.

A positioning system according to an embodiment of the present invention includes a base station. The base station includes a positioning signal receiving circuitry configured to receive a positioning signal and to acquire an electronic signature and a navigation message. The base station also includes a key receiving circuitry configured to receive a public key corresponding to the electronic signature. The base station further includes a base station determination circuitry configured to determine a true navigation message using the electronic signature and the public key. The base station also includes a base station compression message generation circuitry configured to compress the true navigation message to generate a base station compression message. The base station further includes a base station communication circuitry configured to transmit the base station compression message.

The positioning system also includes a positioning device configured to perform positioning. Herein, the positioning device includes a device communication circuitry configured to receive the base station compression message. The positioning device also includes a verification compression message generation circuitry configured to compress the received navigation message of the positioning signal to generate a verification compression message. The positioning device further includes a device determination circuitry configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message. The positioning device also includes a positioning circuitry configured to calculate a position of the positioning device using the positioning signal in which the received navigation message is the true navigation message

In this configuration, the authenticity is determined using the electronic signature and the public key at the base station. Thus, the positioning device does not need to have a high-performance arithmetic processing device. Therefore, a positioning device with a simple configuration can be realized at a low or reduced cost.

In the positioning system according to an embodiment of the present invention, the positioning device includes communication circuitry configured to transfer the verification compression message corresponding to the navigation message determined to be true to another positioning device. Herein, the device determination circuitry of the other positioning device is configured to verify the transferred verification compression message with the verification compression message generated by its own device to determine the authenticity of the received navigation message.

In this configuration, even if the other positioning device is far from the base station and cannot receive the compression message for verification generated by the base station, the authenticity of the received navigation message can be determined using the compression message for verification from the positioning device that can receive the compression message for base station.

Advantageous Effects of the Invention

The present invention enables a positioning device to determine an authenticity of a navigation message and perform positioning using a compressed version of the navigation message in a cost-effective and timely way.

The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. It should be noted that in the accompanying drawings, like or same reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the disclosed embodiments and, together with the detailed description of the disclosure, serve to explain the principles of the disclosed embodiments.
FIG. 1 is a functional block diagram showing an example of a configuration of a positioning system, in accordance with a first embodiment of the present disclosure;
FIG. 2 is a flowchart showing an example of a positioning method, in accordance with the first embodiment of the present disclosure;
FIG. 3 is a functional block diagram showing an example of a configuration of a positioning system, in accordance with a second embodiment of the present disclosure;
FIG. 4 is a flowchart showing an example of a positioning method, in accordance with the second embodiment of the present disclosure;
FIG. 5 is a functional block diagram showing an example of a configuration of a positioning system, in accordance with a third embodiment of the present disclosure;
FIG. 6 is a flowchart showing an example of a positioning method, in accordance with the third embodiment of the present disclosure;
FIG. 7 is a functional block diagram showing an example of a configuration of a positioning system, in accordance with a fourth embodiment of the present disclosure;
FIG. 8 is a flowchart showing an example of processing of a positioning device in a positioning method, in accordance with the fourth embodiment of the present disclosure;
FIG. 9 is a functional block diagram showing an example of a configuration of a positioning system, in accordance with a fifth embodiment of the present disclosure; and
FIG. 10 is a flowchart showing an example of a positioning method, in accordance with the fifth embodiment of the present disclosure.

The diagrams are for illustration only, which thus is not a limitation of the present disclosure. Moreover, those skilled in the art will understand that the drawings are not to scale.

The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.

In the following description, numerous specific details are outlined in order to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that embodiments of the present disclosure may be practiced without some of these specific details. It should be understood that the particular values and configurations discussed in the following non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.

Various embodiments of the present invention have been described below with reference to the drawings. In this specification and each of the drawings, elements that are the same as those described above with respect to the existing drawings are denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

Various embodiments of the present disclosure relate to an improved positioning device with a simple configuration that can perform authenticity determination and positioning. The various embodiments of the present disclosure will be described hereinafter with reference to FIG. 1 to FIG. 10.

FIG. 1 is a functional block diagram showing an example of a configuration of the positioning system 10, in accordance with a first embodiment of the present disclosure. As shown in FIG. 1, the positioning system 10 may include a base station 20 and a positioning device 30. In a non-limiting implementation, the base station 20 is stationary (i.e., the base station 20 does not move) and stores its own position coordinates in advance. In a non-limiting implementation, the positioning device 30 is movable and is capable of determining its own position using a positioning signal. In the illustrated example, satellite (SAT)-A, SAT-B, SAT-C, and SAT-D are Global Navigation Satellite System (GNSS) positioning satellites. In other words, SAT-A, SAT-B, SAT-C, and SAT-D are Global Positioning System (GPS) positioning satellites.

In a non-limiting implementation, SAT-A is configured to broadcast a positioning signal SS-A. In an example, the positioning signal SS-A includes navigation message NAV-A, which is specific to SAT-A.

In a non-limiting implementation, SAT-B is configured to broadcast a positioning signal SS-B. In an example, the positioning signal SS-B includes navigation message NAV-B, which is specific to SAT-B.

In a non-limiting implementation, SAT-C is configured to broadcast a positioning signal SS-C. In an example, the positioning signal SS-C includes navigation message NAV-C, which is specific to SAT-C.

In a non-limiting implementation, SAT-D is configured to broadcast a positioning signal SS-D. In an example, the positioning signal SS-D includes navigation message NAV-D, which is specific to SAT-D.

In various examples, the base station 20 includes an antenna 200, positioning circuitry 21, determination circuitry 22, base station compression message generation circuitry 23, and a communication circuitry 24. It is noted that the positioning circuitry 21, the determination circuitry 22, the base station compression message generation circuitry 23, and the communication circuitry 24 are composed of, for example, an electronic circuit, a computer, or other computing devices. Herein, the positioning circuitry 21 corresponds to the base station positioning circuitry, the determination circuitry 22 corresponds to the base station determination circuitry, and the communication circuitry 24 corresponds to the base station communication circuitry.

In a non-limiting scenario, the antenna 200 is configured to receive the positioning signal SS-A broadcast from the positioning satellite SAT-A, the positioning signal SS-B broadcast from the positioning satellite SAT-B, the positioning signal SS-C broadcast from the positioning satellite SAT-C, and the positioning signal SS-D broadcast from the positioning satellite SAT-D.

It is noted that although FIG. 1 illustrates a scenario in which the positioning signals (i.e., SS-A, SS-B, SS-C, and SS-C) from the four positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D), respectively are received. However, the scenario would still be applicable in an alternate configuration as long as the positioning signals from at least one of the four positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D) are received.

Upon receiving the positioning signals, the antenna 200 is configured to output the received plurality of positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D) to the positioning circuitry 21.

In an embodiment, the positioning circuitry 21 is configured to capture and track the plurality of positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D), respectively. In particular, the positioning circuitry 21 is configured to calculate a code pseudo distance between the plurality of positioning satellites (SAT-A, SAT-B, SAT-C, and SAT-D) and the base station 20 (or the antenna 200) by capturing and tracking techniques.

Then, the positioning circuitry 21 is configured to demodulate the plurality of navigation messages (i.e., NAV-A, NAV-B, NAV-C, and NAV-D) using the capturing and tracking techniques. The demodulation of the plurality of navigation messages (i.e., NAV-A, NAV-B, NAV-C, and NAV-D) using the capturing and tracking techniques generates a plurality of demodulated navigation messages. In a non-limiting implementation, the positioning circuitry 21 acquires or determines satellite orbit information of each one of the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D) from the plurality of demodulated navigation messages.

Further, the positioning circuitry 21 is configured to calculate or compute position coordinates of the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D) from the respective satellite orbit information of the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D).

In another embodiment, the positioning circuitry 21 is configured to compute or calculate position coordinates of the base station 20 using the code pseudo distance between the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, SAT-D) and the base station 20 (or the antenna 200) and position coordinates of the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, SAT-D) based on the satellite orbit information of the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, SAT-D). Then, the positioning circuitry 21 is configured to output or transmit the calculated position coordinates of the base station 20 to the determination circuitry 22.

In an embodiment, the determination circuitry 22 is configured to compare the calculated position coordinates of the base station 20 (i.e., the calculated position coordinates of the base station 20) with the position coordinates of its own station (i.e., the known or pre-stored position coordinates) stored in advance. In response to determining that the error (i.e., the positioning error) between the calculated position coordinates of the base station 20 and the known position coordinates is small, the determination circuitry 22 determines that a positioning signal used for computing the calculated position coordinates of the base station 20 is a true positioning signal. Similarly, it is determined that a navigation message included in the positioning signal is correct, i.e., it is a true navigation message. Here, the phrase ‘true navigation message’ refers to, for example, a navigation message in which the satellite orbit information or the like is not manipulated.

For example, in an aspect, the determination circuitry 22 may set a threshold for determining whether the navigation message or the positioning signal is true or false based on the positioning error. The threshold for this true or false determination can be set based on, for example, DOP (Dilution of Precision) or the like.

Similarly, 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 the true or false determination, the determination circuitry 22 determines that the positioning signal used for the calculated position coordinates of the base station 20 is a true positioning signal. Similarly, it is determined that the navigation message included in the positioning signal is a true navigation message.

On the other hand, if the three-dimensional distance difference between the calculated position coordinates of the base station 20 and the known position coordinates is more than the threshold for the true or false determination, the determination circuitry 22 determines that at least one of the positioning signals used for the calculated position coordinates of the base station 20 is a false positioning signal. Similarly, it is determined that the navigation message included in the positioning signal is a false navigation message.

Here, the phrase ‘false navigation message’ refers to, for example, a navigation message in which the satellite orbit information or the like is intentionally manipulated so that a position coordinate different from the original position coordinate (or true position coordinate) is obtained by someone with malicious intent. Therefore, if the positioning is performed using a false positioning signal including a false navigation message, the three-dimensional distance difference between the calculated position coordinates of the base station 20 and the known position coordinates becomes large. This large difference is detected and flagged by the determination circuitry 22. To that end by utilizing this feature, the determination circuitry 22 can determine the true navigation message and the false navigation message with high accuracy.

In another embodiment, in response to determining (by the determination circuitry 22) that the false navigation message is included in the positioning signal, the determination circuitry 22 informs or notifies the positioning circuitry 21. For example, in response to determining the presence of a false navigation message, the determination circuitry 22 transmits a notification to the positioning circuitry 21. Based on this notification, the positioning circuitry 21 calculates the position coordinates of the base station 20 by changing the combination of the positioning signals. Then, the determination circuitry 22 determines the true navigation message and the false navigation message using a new combination of the positioning signals.

As may be understood, the positioning circuitry 21 may calculate the position coordinates of the base station 20 for each combination of the plurality of positioning signals (e.g., the five or more positioning signals) received in advance. In such a scenario case, the determination circuitry 22 may determine the true navigation message and the false navigation message for each combination of the navigation messages present in the positioning signal.

It is noted that the determination circuitry 22 may determine whether the navigation message is the true navigation message or false using not only the position coordinates but also the time as well. Specifically, the determination circuitry 22 may be configured to compare the time of the base station 20 calculated at the time of positioning with the time of its own station (i.e., the base station 20) stored in advance. In particular, the determination circuitry 22 may determine that the navigation message is the true navigation message (i.e., a true navigation message) if the calculated time and the previously stored time information are the same. In a non-limiting scenario, the determination circuitry 22 may determine that the navigation message is the true navigation message if the difference between the calculated time and the previously stored time information is within a predetermined error range. On the other hand, if the difference between the calculated time and the previously stored time information is larger than the predetermined error range, the determination circuitry 22 determines that the navigation message is false, i.e., a false navigation message.

To that end, in an aspect, the determination circuitry 22 may determine that the navigation message identified as a true using both the position coordinates and the time as the ‘final true navigation message’. It is noted that although a scenario for using both the position coordinates and the time for identifying or determining whether the navigation message is the true navigation message or false has been described herein. It is also possible to determine whether the navigation message is the true navigation message or false using either only the position coordinates or the time as well. To that end, if only time is used for the determination process, then the positioning circuitry 21 corresponds to the "base station time calculation circuitry" of the present invention.

Further, the determination circuitry 22 is configured to output the true navigation message to the base station compression message generation circuitry 23. Alternatively, the determination circuitry 22 is configured to output the unique ID of the positioning satellite corresponding to the true navigation message to the base station compression message generation circuitry 23. Then, the base station compression message generation circuitry 23 may acquire the true navigation message from the positioning circuitry 21 based on the unique ID.

In an embodiment, the base station compression message generation circuitry 23 is configured to compress the true navigation message to generate a base station compression message. Herein, the base station compression message is composed of the data extracted from a part or portion of the true navigation message. For example, the base station compression message is composed of the data extracted from the satellite orbit information (i.e., the ephemeris information) in the true navigation message. Similarly, the base station compression message circuitry 23 is configured to generate a base station compression message for each of the plurality of navigation messages determined to be true.

Then, the base station compression message circuitry 23 outputs the base station compression message to the communication circuitry 24. The communication circuitry 24 transmits the base station compression message to communication circuitry 32 of the positioning device 30.

In various examples, the positioning device 30 includes an antenna 300, a verification compression message generator 31, the communication circuitry 32, determination circuitry 33, and positioning circuitry 34. Herein, the verification compression message generator 31, the communication circuitry 32, the determination circuitry 33, and the positioning circuitry 34 are composed of an arithmetic processing circuitry such as an electronic circuit or a computer. In various instances, the communication circuitry 32 corresponds to the "device communication circuitry," and the determination circuitry 33 corresponds to the "device determination circuitry."

In a non-limiting scenario, the antenna 300 receives the positioning signal SS-A broadcast from the positioning satellite SAT-A, the positioning signal SS-B broadcast from the positioning satellite SAT-B, the positioning signal SS-C broadcast from the positioning satellite SAT-C, and the positioning signal SS-D broadcast from the positioning satellite SAT-D.

Then, the antenna 300 outputs the received plurality of positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D) to the verification compression message generator 31 and the positioning circuitry 34.

In a non-limiting implementation, the verification compression message generator 31 demodulates the navigation messages (i.e., NAV-A, NAV-B, NAV-C, and NAV-D) from the plurality of positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D), respectively. Then, the verification compression message generator 31 compresses the navigation messages (i.e., NAV-A, NAV-B, NAV-C, and NAV-D), and generates verification compression messages corresponding to the respective navigation messages. It is noted that the method of generating the compression message for verification by the verification compression message generator 31 is similar to the method of generating the compression message for the base station 20 for verification by the base station compression message generation circuitry 23 described earlier. To that end, the same is not described again for the sake of brevity.

Then, the verification compression message generator 31 outputs the generated compression message for verification to the determination circuitry 33.

The communication circuitry 32 receives the compression message for verification from the communication circuitry 24 of the base station 20. The communication circuitry 32 outputs the compression message for the base station 20 to the determination circuitry 33.

Then, the determination circuitry 33 verifies the generated compression message for verification with the received compression message for verification. If the generated compression message for verification has the same data structure as the received compression message for verification, then the determination circuitry 33 determines that the original navigation message of the compression message for verification is a true navigation message.

Alternatively, if the generated compression message for verification does not have the same data structure as the received compression message for verification, then the determination circuitry 33 determines that the original navigation message of the compression message for verification is a false navigation message.

Now, the determination circuitry 33 performs the previously described determination process for each navigation message, in other words, for each positioning signal or for each positioning satellite. That is, the determination circuitry 33 selects the compression message for verification and the compression message for the base station 20 based on the unique ID of the positioning satellite. Then, the determination circuitry 33 determines the authenticity of the navigation message using the selected compression message for verification and the compression message for the base station 20. Further, the determination circuitry 33 outputs the authenticity determination result of the navigation message to the positioning circuitry 34.

The positioning circuitry 34 calculates the position coordinates of the positioning device 30 (positioning of the positioning device 30) based on the authenticity determination result of the navigation message. More specifically, the positioning circuitry 34 calculates the position coordinates of the positioning device 30 (positioning of the positioning device 30) using the original positioning signal of the true navigation message.

With this configuration, the positioning device 30 can suppress the use of false positioning signals (or false navigation messages) and perform positioning using only the true positioning signal. Therefore, the positioning device 30 can achieve high-precision positioning.

Furthermore, the positioning device 30 can determine the authenticity of the navigation message and the positioning signal by simple arithmetic processing using the compressed navigation message. As a result, the positioning device 30 can perform authenticity determination and positioning at high speed, and a simple configuration that can be reduced in cost can be realized.

FIG. 2 is a flowchart showing an example of the positioning method, in accordance with the first embodiment of the present disclosure. It should be noted that the specific contents of each process in FIG. 2 have been described earlier with reference to FIG. 1. To that end, a description for the same is omitted herein except for the sections that require additional explanation for the sake of brevity. In the following description, the base station 20 and the positioning device 30 will be described as subjects with reference to FIG. 2, but each process is executed in each functional section as described in the description with reference to FIG. 1.

At step S21, the base station 20 is configured to calculate the position coordinates of the base station 20 (i.e., the position the base station 20) using the positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D) broadcasted from the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D.

At step S22, the base station 20 is configured to determine the true navigation message using the positioning result (i.e., the calculated position coordinates). More specifically, the base station 20 determines the true navigation message and the false navigation message using the error between the position coordinates of its own station stored in advance and the positioning result (i.e., calculated position coordinates).

At step S23, the base station 20 is configured to generate the base station compression message using the true navigation message.

At step S24, the base station 20 is configured to transmit the base station compression message to the positioning device 30.

At step S31, the positioning device 30 is configured to demodulate the navigation message from the positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D) broadcasted from the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D), and generate the compression message for verification.

At step S32, the positioning device 30 is configured to receive the base station compression message from the base station 20. It is noted that the order of steps S31 and S32 is not limited to the order shown with reference to FIG. 2, other orders for these steps are also possible.

At step S33, the positioning device 30 is configured to compare the compression message for verification with the base station compression message, and determines the authenticity of the navigation message. More specifically, the positioning device 30 compares the compression message for verification with the base station compression message for each demodulated navigation message. If the verification compression message and the base station compression message have the same data structure (i.e., if they match), the positioning device 30 determines that the navigation message as the source of the verification compression message is a true navigation message. On the other hand, if the verification compression message and the base station compression message do not have the same data structure (i.e., if they do not match), the positioning device 30 determines that the navigation message as the source of the verification compression message is a false navigation message.

At step S34, using the true navigation message and the positioning signal, the positioning device 30 is configured to calculate the position coordinates of the positioning device 30 (i.e., positioning the positioning device 30).

FIG. 3 is a functional block diagram showing an example of the configuration of a positioning system 10A, in accordance with a second embodiment of the present disclosure. As shown in FIG. 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 20(1), Base Station 20(2), Base Station 20(3)), a management base station 40, and the positioning device 30 determines the authenticity of the navigation message based on information from the management base station 40. It is noted that the remaining components or configuration of the positioning system 10A is similar or identical to that of the positioning system 10. To that end, the description of the similar or identical components or the configuration has been omitted herein for the sake of brevity.

In various examples, the positioning system 10A includes a plurality of base stations (see, Base Station 20(1), Base Station 20(2), Base Station 20(3)), a positioning device 30, and a management base station 40. It is noted that the number of base stations shown herein, is not limited to three, but may be more or less as well.

It is understood that the base stations 20(1), 20(2), and 20(3) have the same configuration as that of the base station 20 according to the first embodiment. Each of the base stations 20(1), 20(2), and 20(3) is configured to perform the authenticity determination process for each navigation message (i.e., per positioning signal, per positioning satellite). Each of the base stations 20(1), 20(2), and 20(3) is configured to transmit each authenticity determination result and the base station compression message determined to be true to the management base station 40.

In various examples, the management base station 40 may include communication circuitry 41 and message determination circuitry 42. The communication circuitry 41 receives the authenticity determination result and the base station compression message determined to be true from the base stations 20(1), 20(2), and 20(3). Then, the communication circuitry 41 outputs the authenticity determination results to the message determination circuitry 42.

In an embodiment, the message determination circuitry 42 performs the authenticity determination process as preparation for transmission to the positioning device 30 based on the authenticity determination result determined by the plurality of base stations 20(1), 20(2), and 20(3) for one navigation message (i.e., the positioning signal and positioning satellite). More specifically, the message determination circuitry 42 determines that the navigation message is a true navigation message if the number of true determinations is large for one navigation message (positioning signal and positioning satellite). On the other hand, the message determination circuitry 42 determines that the navigation message is a false navigation message if the number of false determinations is large for one navigation message (positioning signal and positioning satellite).

In another embodiment, the message determination circuitry 42 determines that the base station compression message of the navigation message determined to be a true navigation message as a transmission base station compression message.

Further, the communication circuitry 41 transmits the transmission base station compression message determined by the message determination circuitry 42 to the positioning device 30.

The positioning device 30 uses the transmission base station compression message to determine the authenticity of the navigation message of the received positioning signal and perform positioning, as described in the first embodiment with reference to FIG. 1.

As per the configuration described using the second embodiment, since the positioning system 10A refers to the authenticity determination results of the plurality of base stations 20(1), 20(2), and 20(3), the reliability of the authenticity determination of the navigation message can be improved.

In addition, the positioning system 10A uses a majority vote for the authenticity determination. Thus, the positioning system 10A can easily determine the authenticity of the navigation message and speed up the authenticity determination processing.

It is noted that within the proposed configuration, the plurality of base stations 20(1), 20(2), and 20(3) and the management base station 40 have been described as separate entities. However, in some instances, at least one of the plurality of base stations 20(1), 20(2), and 20(3) may be used to perform the functions or operations of the management base station 40 as well.

In addition, in the positioning system 10A, although the majority vote or decision has been used for authenticity determination as an example, it is also possible to transmit the base station compression message of the navigation message determined to be true by all the base stations 20(1), 20(2), and 20(3) to the positioning device 30.

FIG. 4 is a flowchart showing an example of the positioning method, in accordance with the second embodiment of the present disclosure. In the positioning method according to the second embodiment, the basic processing of the base stations 20(1), 20(2), and 20(3) and the basic processing of the positioning device 30 are the same as those of the positioning method according to the first embodiment, and the description of the similar parts is omitted.

At step S24A, each of the plurality of base stations 20(1), 20(2), and 20(3) transmit the authenticity determination result and the base station compression message to the management base station 40. The process for generating and transmitting the authenticity determination result and the base station compression message has already been described with reference to steps S21 to S24 of FIG. 2. To that end, the same has not been explained again for the sake of brevity.

At step S41, the management base station 40 is configured to receive the authenticity determination result and the base station compression message from each of the plurality of base stations 20(1), 20(2), and 20(3).

At step S42, the management base station 40 is configured to determine the transmission base station compression message from the plurality of base station compression messages based on the plurality of authenticity determination results.

At step S43, the management base station 40 is configured to transmit the transmission base station compression message to the positioning device 30.

It is noted that steps S31 and S34 have already been described with reference to FIG. 2. To that end, the same has not been explained again for the sake of brevity.

Then, at step S32A, the positioning device 30 is configured to receive the transmission base station compression message.

Then, at step S33A, the positioning device 30 determines the authenticity of the navigation message using the transmission base station compression message.

FIG. 5 is a functional block diagram showing an example of the configuration of the positioning system 10B, in accordance with a third embodiment of the present disclosure.

As shown in FIG. 5, the positioning system 10B according to the third embodiment differs from the positioning system 10 according to the first embodiment in that it determines the authenticity of the navigation message using an electronic signature and a key (i.e., a public key). It is noted that the remaining components or configuration of the positioning system 10B is similar or identical to that of the positioning system 10. To that end, the description of the similar or identical components or the configuration has been omitted herein for the sake of brevity.

In various examples, the positioning system 10B includes a base station 20B, a positioning device 30, and a positioning system management station 50. In a non-limiting implementation, the positioning system management station 50 includes electronic signature issuing circuitry 51, key issuing circuitry 52, electronic signature transmitting circuitry 53, and key transmitting circuitry 54.

In a non-limiting scenario, the electronic signature issuing circuitry 51 is configured to issue an electronic signature of the positioning system 10B to which the positioning satellites, i.e., SAT-A, SAT-B, SAT-C, and SAT-D belong. The key issuing circuitry 52 issues a key (i.e., public key) corresponding to the electronic signature issued by the electronic signature issuing circuitry 51. Then, the electronic signature transmitting circuitry 53 transmits the electronic signature to the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D).

It is noted that as described earlier, the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D) respectively broadcast positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D) including the electronic signature together with the navigation message.

Then, key transmitting circuitry 54 transmits the key to the base station 20B.

Herein, the base station 20B includes key receiving circuitry 25. The key receiving circuitry 25 is configured to receive the key and output it to a determining circuitry 22B.

In an embodiment, the determining circuitry 22B determines the authenticity of the navigation message by unlocking the electronic signature included in the positioning signal with the key and collating the contents of the electronic signature.

The determining circuitry 22B finally determines the authenticity of the navigation message based on the authenticity determination based on the position coordinates as described in the first embodiment with reference to FIG. 1 and the authenticity determination based on the combination of the electronic signature and the key.

Specifically, the determination circuitry 22B determines that the navigation message is the true navigation message if the determination based on the position coordinates is a true navigation message and the determination based on the combination of the electronic signature and the key is true. On the other hand, the determination circuitry 22B determines that the navigation message is a false navigation message if either the determination based on the position coordinates or the determination based on the combination of the electronic signature and the key is false.

As per the configuration described using the third embodiment, the base station 20B can further improve the accuracy of the determination of the authenticity of the navigation message.

In this configuration, the base station 20B has to be provided with a high-performance arithmetic processing device, but the positioning device 30 does not need to be provided with a high-performance arithmetic processing device. Therefore, a positioning device 30 with a simple configuration can be realized at a low or reduced cost.

FIG. 6 is a flowchart showing an example of the positioning method, in accordance with the third embodiment of the present disclosure. It is noted that only the parts of the positioning method according to the third embodiment that are different from the positioning method according to the first embodiment have been described with reference to FIG. 6. Further, description of portions or parts similar to the first embodiment have not been described again for the sake of brevity.

It is noted that steps S21, S23, S24, S31, S32, S33, and S34 have already been described with reference to FIG. 2. To that end, the same has not been explained again for the sake of brevity.

At step S22B, the base station 20B is configured to determine the true navigation message using the result of matching the electronic signature with the key and the positioning result.

More specifically, the base station 20B is configured to receive and store the key, i.e., the public key. Then, the base station 20B demodulates the electronic signature from the received positioning signal. Then, the base station 20B unlocks the electronic signature with the key and checks the contents of the electronic signature to determine the authenticity of the navigation message.

In particular, the base station 20B compares the position coordinates positioned by the positioning signal with the position information of its own station stored in advance to determine the authenticity of the navigation message. At this time, the base station 20B may determine the authenticity of the navigation message using only the positioning signal determined to be the true navigation message in the determination using the electronic signature and the key.

FIG. 7 is a functional block diagram showing an example of the configuration of a positioning system 10C, in accordance with a fourth embodiment of the present disclosure.

As shown in FIG. 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 (such as a positioning device 30C1 and a positioning device 30C2). It is noted that the positioning device 30C2 cannot directly communicate with the base station 20. It is noted that the remaining components or configuration of the positioning system 10C is similar or identical to that of the positioning system 10. To that end, the description of the similar or identical components or the configuration has been omitted herein for the sake of brevity.

In various examples, the positioning system 10C includes the base station 20, the positioning device 30C1, and the positioning device 30C2. It is noted that the number of positioning stations shown herein, is not limited to two, but may be more than two (i.e., a plurality) as well,

It is noted that the positioning device 30C1 and the positioning device 30C2 have basically the same configuration as that of the positioning device 30 according to the first embodiment, but differ in that they include communication circuitry 32C is capable of mutual communication.

In the example of FIG. 7, the positioning device 30C1 can directly communicate with the base station 20. On the other hand, the positioning device 30C2 cannot directly communicate with the base station 20, but can directly communicate with the positioning device 30C1. It should be noted that the phrase “direct communication is not possible” here is not limited to the case where the distance from the base station 20 to the positioning device 30C2 is too long to receive communication radio waves, but also includes the case where the communication specification of the positioning device 30C2 is different from the base station 20.

As with the positioning device 30 according to the first embodiment, the positioning device 30C1 uses the base station compression 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.

When the positioning device 30C2 detects that the base station compression message cannot be received, it makes a transfer request to the communicable positioning devices 30C1 through the corresponding communication circuitry 32C, respectively.

When the transfer request is received, the positioning device 30C1 transfers the verification compression message determined to be the true navigation message to the positioning device 30C2 through the corresponding communication circuitry 32C, respectively.

Further, the positioning device 30C2 uses the verification compression message determined to be the true navigation message by the positioning device 30C1 to determine the authenticity of the navigation message of the positioning signal received by the positioning device 30C2. Thereafter, the positioning device 30C1 may transfer the base station compression message to the positioning device 30C2.

As per the configuration described using the fourth embodiment, even if the positioning device 30C2 cannot directly receive the base station compression message from the base station 20, it is possible to suppress the use of the false positioning signal and perform positioning using only the true positioning signal. Therefore, the positioning device 30C2 can realize high-precision positioning as well.

FIG. 8 is a flowchart showing an example of the processing of a positioning device in the positioning method, in accordance with the fourth embodiment of the present disclosure.

At step S31, the positioning devices 30C1 and 30C2 are configured to demodulate the navigation message from the positioning signals (i.e., SS-A, SS-B, SS-C, and SS-D) broadcast from the plurality of positioning satellites (i.e., SAT-A, SAT-B, SAT-C, and SAT-D) to generate a compression message for verification.

Then, if the positioning device 30C1 can receive the base station compression message (i.e., at step S32C: YES), then, at step S33C, the positioning device 30C1 compares the compression message for verification with the base station compression message and determines the authenticity of the navigation message.

Alternatively, if the positioning device 30C2 cannot receive the compression message for base station (i.e., at step S32C: NO), the positioning device 30C2 makes a transfer request to the other positioning device 30C1.

Then, at step S35, the positioning device 30C2 is configured to receive the compression message for verification determined to be true and transferred from the other positioning device 30C1.

Then, at step S36, the positioning device 30C2 is configured to determine the authenticity of the navigation message using the transferred compression message for verification.

At step S34, the positioning devices 30C1 and 30C2 are configured to use the true navigation message and its positioning signal to position the position coordinates of the positioning devices 30C1 and 30C2.

FIG. 9 is a functional block diagram showing an example of the configuration of a positioning system 10D, in accordance with a fifth embodiment of the present disclosure.

As shown in FIG. 9, the positioning system 10D according to the fifth embodiment differs from the positioning system 10B according to the third embodiment in that the authenticity of the navigation message is determined using only the electronic signature and the key (public key). It is noted that the remaining components or configuration of the positioning system 10D is similar or identical to that of the positioning system 10B. To that end, the description of the similar or identical components or the configuration has been omitted herein for the sake of brevity.

In various examples, the positioning system 10D includes a base station 20D, a positioning device 30, and a positioning system management station 50. In particular, the base station 20D includes positioning signal reception circuitry 21D and determination circuitry 22D.

In a non-limiting implementation, the positioning signal reception circuitry 21D receives the positioning signal and acquires an electronic signature and a navigation message.

Then, the key reception circuitry 25 of the base station 20D receives the key (i.e., the public key) and outputs it to the determination circuitry 22D.

In an embodiment, the determination circuitry 22D determines the authenticity of the navigation message by unlocking the electronic signature included in the positioning signal with the key and checking the contents of the electronic signature.

The base station compression message generation circuitry 23 generates a base station compression message from the true navigation message determined using only the electronic signature and the key by the determination circuitry 22D.

As per the configuration described using the fifth embodiment, the base station 20D needs to be provided with a high-performance arithmetic processing apparatus, but the positioning apparatus 30 does not need to be provided with a high-performance arithmetic processing apparatus. Therefore, it is possible to realize a simple positioning apparatus 30 capable of reducing the cost.

FIG. 10 is a flowchart showing an example of the positioning method, in accordance with the fifth embodiment of the present disclosure. It is noted that only the parts of the positioning method according to the fifth embodiment that are different from the positioning method according to the third embodiment have been described with reference to FIG. 10. Further, description of portions or parts similar to the third embodiment have not been described again for the sake of brevity.

At step S22D, the base station 20D is configured to determine the true navigation message using the result of checking the electronic signature and the key.

It is noted that the configurations and methods of the various embodiments herein in the present disclosure can be appropriately combined, and the operation and effect corresponding to each combination can be achieved.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and of course, various modifications can be made by those skilled in the art. Moreover, the respective embodiments can be used in combination as appropriate.

Representative embodiments of the present invention have been described below.

(1) A positioning system 10, 10 A, 10B, 10 C, 10D comprising: a base station storing position information of the base station in advance, wherein the base station comprises: base station positioning circuitry 21, 34 configured to calculate a position of the base station using a received positioning signal; base station determination circuitry 22, 22B, 22D, 33 configured to determine a true navigation message using a condition, wherein the calculated position of the base station is approximate to the pre-stored position information of the base station; base station compression message generation circuitry 23 configured to compress the true navigation message to generate a base station compression message; and base station communication circuitry 24, 32, 32C, 41 configured to transmit the base station compression message; and a positioning device 30, 30C1, 30C2 configured to perform positioning, wherein the positioning device 30, 30C1, 30C2 comprises: device communication circuitry 24, 32, 32C, 41 configured to receive the base station compression message; verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message; device determination circuitry 22, 22B, 22D, 33 configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and positioning circuitry 21, 34 configured to calculate the position of the positioning device 30, 30C1, 30C2 using the received positioning signal in which the received navigation message is the true navigation message.

(2) The positioning system 10, 10 A, 10B, 10 C, 10D according to (1), wherein: the base station positioning circuitry 21, 34 is further configured to calculate a time of the base station using the received positioning signal, and the base station determination circuitry is further configured to determine the true navigation message using another condition, wherein the calculated time of the base station is approximate to the pre-stored time information of the base station.

(3) The positioning system 10, 10 A, 10B, 10 C, 10D according to (1), wherein the base station compression message generation circuitry 23 is further configured to generate the base station compression message using an electronic signature and a public key issued by the positioning system 10, 10 A, 10B, 10 C, 10D to which a positioning satellite belongs.

(4) The positioning system 10, 10 A, 10B, 10 C, 10D according to (1), wherein the positioning device 30, 30C1, 30C2 further comprises: communication circuitry 24, 32, 32C, 41 configured to transfer the verification compression message corresponding to the navigation message determined to be true to another positioning device 30, 30C1, 30C2; and the device determination circuitry 22, 22B, 22D, 33 of the other positioning device 30, 30C1, 30C2 is configured to verify the transferred verification compression message with the verification compression message generated by its own device to determine the authenticity of the received navigation message.

(5) A positioning system 10, 10 A, 10B, 10 C, 10D comprising: a base station storing time information of the base station in advance, wherein the base station comprises: a base station positioning circuitry 21, 34 configured to calculate a time of the base station using a received positioning signal; a base station determination circuitry 22, 22B, 22D, 33 configured to determine a true navigation message using a condition, wherein the calculated time of the base station is approximate to the pre-stored time information of the base station; a base station compression message generation circuitry 23 configured to compress the true navigation message to generate a base station compression message; and a base station communication circuitry 24, 32, 32C, 41 configured to transmit the base station compression message; and a positioning device 30, 30C1, 30C2 configured to perform positioning, wherein the positioning device 30, 30C1, 30C2 comprises: a device communication circuitry 24, 32, 32C, 41 configured to receive the base station compression message; a verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message; a device determination circuitry 22, 22B, 22D, 33 configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and a positioning circuitry 21, 34 configured to calculate a position of the positioning device 30, 30C1, 30C2 using the received positioning signal in which the received navigation message is the true navigation message.

(6) The positioning system 10, 10 A, 10B, 10 C, 10D according to (5), wherein the base station compression message generation circuitry 23 is further configured to generate the base station compression message using an electronic signature and a public key issued by the positioning system 10, 10 A, 10B, 10 C, 10D to which a positioning satellite belongs.

(7) A positioning system 10, 10 A, 10B, 10 C, 10D comprising: a plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3), wherein each base station of the plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3) stores position information of the each base station in advance, wherein the each base station of the plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3) comprises: base station positioning circuitry 21, 34 configured to calculate a position of the each base station using a received positioning signal; base station determination circuitry 22, 22B, 22D, 33 configured to determine an authenticity of a true navigation message using a condition wherein the calculated position of the each base station is approximate to the pre-stored stored position information of the each base station; base station compression message generation circuitry 23 configured to compress the true navigation message to generate a base station compression message; and base station communication circuitry 24, 32, 32C, 41 configured to transmit an authenticity determination result and the base station compression message; a management base station 40 configured to manage the plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3), wherein the management base station 40 comprises: management base station 40 communication circuitry 24, 32, 32C, 41 configured to transmit and receive the authenticity determination result, and the base station compression message; and message determination circuitry 42 configured to compare a plurality of base station compression messages to determine the base station compression message for transmission; and a positioning device 30, 30C1, 30C2 configured to perform positioning, wherein the positioning device 30, 30C1, 30C2 comprises: device communication circuitry 24, 32, 32C, 41 configured to receive the base station compression message; verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message; device determination circuitry 22, 22B, 22D, 33 configured to verify the base station compression message with the verification compression message to determine the authenticity of the received navigation message; and positioning circuitry 21, 34 configured to calculate the position of the positioning device 30, 30C1, 30C2 using the received positioning signal in which the received navigation message is the true navigation message.

(8) The positioning system 10, 10 A, 10B, 10 C, 10D according to (7), wherein: the base station positioning circuitry 21, 34 is further configured to calculate a time of the each base station using the received positioning signal; and the base station determination circuitry 22, 22B, 22D, 33 is further configured to determine the true navigation message using another condition, wherein the calculated position of the each base station is approximate to the pre-stored position information of the each base station.

(9) The positioning system 10, 10 A, 10B, 10 C, 10D according to (7), wherein the message determination circuitry 42 is further configured to determine the base station compression message having a largest number of identical base station compression messages as the base station compression message for transmission.

(10) The positioning system 10, 10 A, 10B, 10 C, 10D according to (7), wherein the message determination circuitry 42 is further configured to determine that the navigation message is a true navigation message if the number of true determinations is large for one navigation message, or to determine that the navigation message is a false navigation message if the number of false determinations is large for one navigation message; as the base station compression message for transmission.

(11) The positioning system 10, 10 A, 10B, 10 C, 10D according to (7), wherein the base station compression message generation circuitry 23 is further configured to generate the base station compression message using an electronic signature and a public key issued by the positioning system 10, 10 A, 10B, 10 C, 10D to which a positioning satellite belongs.

(12) A positioning system 10, 10 A, 10B, 10 C, 10D comprising: a plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3), wherein each base station of the plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3) stores time information of the each base station in advance, wherein the each base station of the plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3) comprises: base station positioning circuitry 21, 34 configured to calculate a time of the each base station using a received positioning signal; base station determination circuitry 22, 22B, 22D, 33 configured to determine an authenticity of a true navigation message using a condition wherein the calculated time of the each base station is approximate to the pre-stored stored time information of the each base station; base station compression message generation circuitry 23 configured to compress the true navigation message to generate a base station compression message; and base station communication circuitry 24, 32, 32C, 41 configured to transmit an authenticity determination result and the base station compression message; a management base station 40 configured to manage the plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3), wherein the management base station 40 comprises: management base station 40 communication circuitry 24, 32, 32C, 41 configured to transmit and receive the authenticity determination result, and the base station compression message; and message determination circuitry 42 configured to compare a plurality of base station compression messages to determine the base station compression message for transmission; and a positioning device 30, 30C1, 30C2 configured to perform positioning, wherein the positioning device 30, 30C1, 30C2 comprises: device communication circuitry 24, 32, 32C, 41 configured to receive the base station compression message; verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message; device determination circuitry 22, 22B, 22D, 33 configured to verify the base station compression message with the verification compression message to determine the authenticity of the received navigation message; and positioning circuitry 21, 34 configured to calculate the position of the positioning device 30, 30C1, 30C2 using the received positioning signal in which the received navigation message is the true navigation message.

(13) A positioning system 10, 10 A, 10B, 10 C, 10D comprising: a base station, wherein the base station comprises: a positioning signal receiving circuitry configured to receive a positioning signal and to acquire an electronic signature and a navigation message; a key receiving circuitry 25 configured to receive a public key corresponding to the electronic signature; a base station determination circuitry 22, 22B, 22D, 33 configured to determine a true navigation message using the electronic signature and the public key; a base station compression message generation circuitry 23 configured to compress the true navigation message to generate a base station compression message; and a base station communication circuitry 24, 32, 32C, 41 configured to transmit the base station compression message; and a positioning device 30, 30C1, 30C2 configured to perform positioning, wherein the positioning device 30, 30C1, 30C2 comprises: a device communication circuitry 24, 32, 32C, 41 configured to receive the base station compression message; a verification compression message generation circuitry configured to compress the received navigation message of the positioning signal to generate a verification compression message; a device determination circuitry 22, 22B, 22D, 33 configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and a positioning circuitry 21, 34 configured to calculate a position of the positioning device 30, 30C1, 30C2 using the positioning signal in which the received navigation message is the true navigation message.

(14) A positioning method comprising: calculating a position of a base station using a received positioning signal; determining a true navigation message using a condition, wherein the calculated position of the base station is approximate to a pre-stored position information of the base station; compressing the true navigation message to generate a base station compression message; transmitting the base station compression message; compressing a received navigation message of the received positioning signal to generate a verification compression message; verifying the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and calculating the position of a positioning device 30, 30C1, 30C2 using the received positioning signal in which the received navigation message is the true navigation message.

(15) A positioning method comprising: by each base station of a plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3), storing position information of the each base station in advance, calculating a position of the each base station using a received positioning signal; determining an authenticity of a navigation message using a condition that the calculated position of the each base station is approximate to the previously stored position information of the each base station; compressing a true navigation message to generate a base station compression message; and transmitting an authenticity determination result and the base station compression message; by a management base station 40, transmitting and receiving the authenticity determination result, and the base station compression message; and comparing a plurality of base station compression messages and determining the base station compression message for transmission; and by a positioning device 30, 30C1, 30C2, receiving the base station compression message; compressing a received navigation message of the received positioning signal to generate a verification compression message; verifying the base station compression message for transmission with the verification compression message and determining an authenticity of the received navigation message; and calculating the position of the positioning device 30, 30C1, 30C2 using the received positioning signal in which the received navigation message is the true navigation message.

(16) A non-transient computer-readable medium containing program instructions for causing a computer to execute a method of: calculating a position of a base station using a received positioning signal; determining a true navigation message using a condition, wherein the calculated position of the base station is approximate to a pre-stored position information of the base station; compressing the true navigation message and generating a base station compression message; transmitting the base station compression message; compressing a received navigation message of the received positioning signal and generating a verification compression message; verifying the base station compression message with the verification compression message and determining an authenticity of the received navigation message; and calculating the position of the positioning device 30, 30C1, 30C2 using the received positioning signal in which the received navigation message is the true navigation message.

(17) A non-transient computer-readable medium containing program instructions for causing a computer to execute a method of: by each base station of a plurality of base stations 20, 20B, 20D, 20(1), 20(2), 20(3), storing position information of the each base station in advance, calculating a position of the each base station using a received positioning signal; determining an authenticity of a navigation message using a condition that the calculated position of the each base station is approximate to the pre-stored stored position information of the each base station; compressing a true navigation message and generating a base station compression message; and transmitting an authenticity determination result and the base station compression message; by a management base station 40, transmitting and receiving the authenticity determination result, and the base station compression message; and comparing a plurality of base station compression messages to determine the base station compression message for transmission; and by a positioning device 30, 30C1, 30C2, receiving the base station compression message; compressing a received navigation message of the received positioning signal and generating a verification compression message; verifying the base station compression message for transmission with the verification compression message and determining the authenticity of the received navigation message; and calculating the position of the positioning device 30, 30C1, 30C2 using a positioning signal in which the received navigation message is the true navigation message.

Terminology

It is to be understood that not necessarily all objects or advantages may be achieved in accordance with any particular embodiment described herein. Thus, for example, those skilled in the art will recognize that certain embodiments may be configured to operate in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

All of the processes described herein may be embodied in, and fully automated via, software code modules executed by a computing system that includes one or more computers or processors. The code modules may be stored in any type of non-transitory computer-readable medium or other computer storage device. Some or all the methods may be embodied in specialized computer hardware.

Many other variations than those described herein will be apparent from this disclosure. For example, depending on the embodiment, certain acts, events, or functions of any of the algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the algorithms). Moreover, in certain embodiments, acts or events can be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially. In addition, different tasks or processes can be performed by different machines and/or computing systems that can function together.

The various illustrative logical blocks and modules described in connection with the embodiments disclosed herein can be implemented or performed by a machine, such as a processor. A processor can be a microprocessor, but in the alternative, the processor can be a controller, microcontroller, or state machine, combinations of the same, or the like. A processor can include electrical circuitry configured to process computer-executable instructions. In another embodiment, a processor includes an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable device that performs logic operations without processing computer-executable instructions.

A processor can also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor may also include primarily analog components. For example, some or all of the signal processing algorithms described herein may be implemented in analog circuitry or mixed analog and digital circuitry. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few.

Conditional language such as, among others, "can", "could", "might" or "may" unless specifically stated otherwise, are otherwise understood within the context as used in general to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment.

Disjunctive language such as the phrase "at least one of X, Y, or Z" unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.

Any process descriptions, elements or blocks in the flow diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or members of code which include one or more executable instructions for implementing specific logical functions or elements in the process. Alternate implementations are included within the scope of the embodiments described herein in which elements or functions may be deleted, executed out of order from that shown, or discussed, including substantially concurrently or in reverse order, depending on the functionality involved as would be understood by those skilled in the art.

Unless otherwise explicitly stated, articles such as "a" or "an" should generally be interpreted to include one or more described items. Accordingly, phrases such as "a device configured to" are intended to include one or more recited devices. Such one or more recited devices can also be collectively configured to carry out the stated recitations. For example, "a processor configured to carry out recitations A, B and C" can include a first processor configured to carry out recitation A working in conjunction with a second processor configured to carry out recitations B and C. The same holds true for the use of definite articles used to introduce embodiment recitations. In addition, even if a specific number of an introduced embodiment recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations" without other modifiers, typically means at least two recitations, or two or more recitations).

It will be understood by those within the art that, in general, terms used herein, are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to" the term "having" should be interpreted as "having at least" the term "includes" should be interpreted as "includes but is not limited to" etc.).

For expository purposes, the term "horizontal" as used herein is defined as a plane parallel to the plane or surface of the floor of the area in which the system being described is used or the method being described is performed, regardless of its orientation. The term "floor" can be interchanged with the term "ground" or "water surface." The term "vertical" refers to a direction perpendicular to the horizontal as just defined. Terms such as "above", "below", "bottom", "top", "side", "higher", "lower", "upper", "over" and "under" are defined with respect to the horizontal plane.

As used herein, the terms "attached", "connected", "mated" and other such relational terms should be construed, unless otherwise noted, to include removable, moveable, fixed, adjustable, and/or releasable connections or attachments. The connections/attachments can include direct connections and/or connections having intermediate structure between the two components discussed.

Numbers preceded by a term such as "approximately", "about" and "substantially" as used herein include the recited numbers, and also represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms "approximately", "about" and "substantially" may refer to an amount that is within less than 10% of the stated amount. Features of embodiments disclosed herein preceded by a term such as "approximately", "about" and "substantially" as used herein represent the feature with some variability that still performs a desired function or achieves a desired result for that feature.

It should be emphasized that many variations and modifications may be made to the above-described embodiments, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

10, 10 A, 10B, 10 C, 10D: Positioning System, 20, 20B, 20D, 20(1), 20(2), 20(3): Base Stations, 21D: Positioning Signal reception circuitry, 22, 22B, 22D, 33: Determination Circuitry, 23: Base station compression message generation circuitry 23, 25: Key Receiving Circuitry, 30, 30C1, 30C2: Positioning Device, 31: Verification compression message generator, 24, 32, 32C, 41: Communication Circuitry, 21, 34: Positioning Circuitry, 40: Management Base Station, 42: Message Determination Circuitry, 50: Positioning System Management Station, 51: Electronic Signature Issuing Circuitry, 52: Key Issuing Circuitry, 53: Electronic Signature Transmitting Circuitry, 54: Key Transmitting circuitry, 200: Antenna, 300: Antenna, NAV-A, NAV-B, NAV-C, NAV-D: Navigation Messages, SAT-A, SAT-B, SAT-C, SAT-D: Positioning satellites, SS-A, SS-B, SS-C, SS-D: Positioning Signals.

Claims

A positioning system (10, 10 A, 10B, 10 C, 10D) comprising:
a base station storing position information of the base station in advance, wherein
the base station comprises:
base station positioning circuitry (21, 34) configured to calculate a position of the base station using a received positioning signal;
base station determination circuitry (22, 22B, 22D, 33) configured to determine a true navigation message using a condition, wherein the calculated position of the base station is approximate to position information of the base station;
base station compression message generation circuitry (23) configured to compress the true navigation message to generate a base station compression message; and
base station communication circuitry (24, 32, 32C, 41) configured to transmit the base station compression message; and
a positioning device (30, 30C1, 30C2) configured to perform positioning, wherein the positioning device (30, 30C1, 30C2) comprises:
device communication circuitry (24, 32, 32C, 41) configured to receive the base station compression message;
verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message;
device determination circuitry (22, 22B, 22D, 33) configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and
positioning circuitry (21, 34) configured to calculate the position of the positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 1, wherein:
the base station positioning circuitry (21, 34) is further configured to calculate a time of the base station using the received positioning signal, and
the base station determination circuitry is further configured to determine the true navigation message using another condition, wherein the calculated time of the base station is approximate to the pre-stored time information of the base station.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 1, wherein
the base station compression message generation circuitry (23) is further configured to generate the base station compression message using an electronic signature and a public key issued by the positioning system (10, 10 A, 10B, 10 C, 10D) to which a positioning satellite belongs.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 1, wherein the positioning device (30, 30C1, 30C2) further comprises:
communication circuitry (24, 32, 32C, 41) configured to transfer the verification compression message corresponding to the navigation message determined to be true to another positioning device (30, 30C1, 30C2); and
the device determination circuitry (22, 22B, 22D, 33) of the other positioning device (30, 30C1, 30C2) is configured to verify the transferred verification compression message with the verification compression message generated by its own device to determine the authenticity of the received navigation message.
A positioning system (10, 10 A, 10B, 10 C, 10D) comprising:
a base station storing time information of the base station in advance, wherein
the base station comprises:
a base station positioning circuitry (21, 34) configured to calculate a time of the base station using a received positioning signal;
a base station determination circuitry (22, 22B, 22D, 33) configured to determine a true navigation message using a condition, wherein the calculated time of the base station is approximate to the pre-stored time information of the base station;
a base station compression message generation circuitry (23) configured to compress the true navigation message to generate a base station compression message; and
a base station communication circuitry (24, 32, 32C, 41) configured to transmit the base station compression message; and
a positioning device (30, 30C1, 30C2) configured to perform positioning, wherein the positioning device (30, 30C1, 30C2) comprises:
a device communication circuitry (24, 32, 32C, 41) configured to receive the base station compression message;
a verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message;
a device determination circuitry (22, 22B, 22D, 33) configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and
a positioning circuitry (21, 34) configured to calculate a position of the positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 5, wherein
the base station compression message generation circuitry (23) is further configured to generate the base station compression message using an electronic signature and a public key issued by the positioning system (10, 10 A, 10B, 10 C, 10D) to which a positioning satellite belongs.
A positioning system (10, 10 A, 10B, 10 C, 10D) comprising:
a plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)), wherein each base station of the plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)) stores position information of the each base station in advance, wherein
the each base station of the plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)) comprises:
base station positioning circuitry (21, 34) configured to calculate a position of the each base station using a received positioning signal;
base station determination circuitry (22, 22B, 22D, 33) configured to determine an authenticity of a true navigation message using a condition wherein the calculated position of the each base station is approximate to the pre-stored stored position information of the each base station;
base station compression message generation circuitry (23) configured to compress the true navigation message to generate a base station compression message; and
base station communication circuitry (24, 32, 32C, 41) configured to transmit an authenticity determination result and the base station compression message;
a management base station (40) configured to manage the plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)), wherein the management base station (40) comprises:
management base station (40) communication circuitry (24, 32, 32C, 41) configured to transmit and receive the authenticity determination result, and the base station compression message; and
message determination circuitry (42) configured to compare a plurality of base station compression messages to determine the base station compression message for transmission; and
a positioning device (30, 30C1, 30C2) configured to perform positioning, wherein
the positioning device (30, 30C1, 30C2) comprises:
device communication circuitry (24, 32, 32C, 41) configured to receive the base station compression message;
verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message;
device determination circuitry (22, 22B, 22D, 33) configured to verify the base station compression message with the verification compression message to determine the authenticity of the received navigation message; and
positioning circuitry (21, 34) configured to calculate the position of the positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 7, wherein:
the base station positioning circuitry (21, 34) is further configured to calculate a time of the each base station using the received positioning signal; and
the base station determination circuitry (22, 22B, 22D, 33) is further configured to determine the true navigation message using another condition, wherein the calculated position of the each base station is approximate to the pre-stored position information of the each base station.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 7, wherein:
the message determination circuitry (42) is further configured to determine the base station compression message having a largest number of identical base station compression messages as the base station compression message for transmission.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 7, wherein:
the message determination circuitry (42) is further configured:
to determine that the navigation message is a true navigation message if the number of true determinations is large for one navigation message, or
to determine that the navigation message is a false navigation message if the number of false determinations is large for one navigation message;
as the base station compression message for transmission.
The positioning system (10, 10 A, 10B, 10 C, 10D) according to claim 7, wherein
the base station compression message generation circuitry (23) is further configured to generate the base station compression message using an electronic signature and a public key issued by the positioning system (10, 10 A, 10B, 10 C, 10D) to which a positioning satellite belongs.
A positioning system (10, 10 A, 10B, 10 C, 10D) comprising:
a plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)), wherein
each base station of the plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)) stores time information of the each base station in advance, wherein the each base station of the plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)) comprises:
base station positioning circuitry (21, 34) configured to calculate a time of the each base station using a received positioning signal;
base station determination circuitry (22, 22B, 22D, 33) configured to determine an authenticity of a true navigation message using a condition wherein the calculated time of the each base station is approximate to the pre-stored stored time information of the each base station;
base station compression message generation circuitry (23) configured to compress the true navigation message to generate a base station compression message; and
base station communication circuitry (24, 32, 32C, 41) configured to transmit an authenticity determination result and the base station compression message;
a management base station (40) configured to manage the plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)), wherein
the management base station (40) comprises:
management base station (40) communication circuitry (24, 32, 32C, 41) configured to transmit and receive the authenticity determination result, and the base station compression message; and
message determination circuitry (42) configured to compare a plurality of base station compression messages to determine the base station compression message for transmission; and
a positioning device (30, 30C1, 30C2) configured to perform positioning, wherein
the positioning device (30, 30C1, 30C2) comprises:
device communication circuitry (24, 32, 32C, 41) configured to receive the base station compression message;
verification compression message generation circuitry configured to compress a received navigation message of the received positioning signal to generate a verification compression message;
device determination circuitry (22, 22B, 22D, 33) configured to verify the base station compression message with the verification compression message to determine the authenticity of the received navigation message; and
positioning circuitry (21, 34) configured to calculate the position of the positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.
A positioning system (10, 10 A, 10B, 10 C, 10D) comprising:
a base station, wherein the base station comprises:
a positioning signal receiving circuitry configured to receive a positioning signal and to acquire an electronic signature and a navigation message;
a key receiving circuitry (25) configured to receive a public key corresponding to the electronic signature;
a base station determination circuitry (22, 22B, 22D, 33) configured to determine a true navigation message using the electronic signature and the public key;
a base station compression message generation circuitry (23) configured to compress the true navigation message to generate a base station compression message; and
a base station communication circuitry (24, 32, 32C, 41) configured to transmit the base station compression message; and
a positioning device (30, 30C1, 30C2) configured to perform positioning, wherein the positioning device (30, 30C1, 30C2) comprises:
a device communication circuitry (24, 32, 32C, 41) configured to receive the base station compression message;
a verification compression message generation circuitry configured to compress the received navigation message of the positioning signal to generate a verification compression message;
a device determination circuitry (22, 22B, 22D, 33) configured to verify the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and
a positioning circuitry (21, 34) configured to calculate a position of the positioning device (30, 30C1, 30C2) using the positioning signal in which the received navigation message is the true navigation message.
A positioning method comprising:
calculating a position of a base station using a received positioning signal;
determining a true navigation message using a condition, wherein the calculated position of the base station is approximate to a pre-stored position information of the base station;
compressing the true navigation message to generate a base station compression message;
transmitting the base station compression message;
compressing a received navigation message of the received positioning signal to generate a verification compression message;
verifying the base station compression message with the verification compression message to determine an authenticity of the received navigation message; and
calculating the position of a positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.
A positioning method comprising:
by each base station of a plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)),
storing position information of the each base station in advance,
calculating a position of the each base station using a received positioning signal;
determining an authenticity of a navigation message using a condition that the calculated position of the each base station is approximate to the previously stored position information of the each base station;
compressing a true navigation message to generate a base station compression message; and
transmitting an authenticity determination result and the base station compression message;
by a management base station (40),
transmitting and receiving the authenticity determination result, and the base station compression message; and
comparing a plurality of base station compression messages and determining the base station compression message for transmission; and
by a positioning device (30, 30C1, 30C2),
receiving the base station compression message;
compressing a received navigation message of the received positioning signal to generate a verification compression message;
verifying the base station compression message for transmission with the verification compression message and determining an authenticity of the received navigation message; and
calculating the position of the positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.
A non-transient computer-readable medium containing program instructions for causing a computer to execute a method of:
calculating a position of a base station using a received positioning signal;
determining a true navigation message using a condition, wherein the calculated position of the base station is approximate to a pre-stored position information of the base station;
compressing the true navigation message and generating a base station compression message;
transmitting the base station compression message;
compressing a received navigation message of the received positioning signal and generating a verification compression message;
verifying the base station compression message with the verification compression message and determining an authenticity of the received navigation message; and
calculating the position of the positioning device (30, 30C1, 30C2) using the received positioning signal in which the received navigation message is the true navigation message.
A non-transient computer-readable medium containing program instructions for causing a computer to execute a method of:
by each base station of a plurality of base stations (20, 20B, 20D, 20(1), 20(2), 20(3)),
storing position information of the each base station in advance,
calculating a position of the each base station using a received positioning signal;
determining an authenticity of a navigation message using a condition that the calculated position of the each base station is approximate to the pre-stored stored position information of the each base station;
compressing a true navigation message and generating a base station compression message; and
transmitting an authenticity determination result and the base station compression message;
by a management base station (40),
transmitting and receiving the authenticity determination result, and the base station compression message; and
comparing a plurality of base station compression messages to determine the base station compression message for transmission; and
by a positioning device (30, 30C1, 30C2),
receiving the base station compression message;
compressing a received navigation message of the received positioning signal and generating a verification compression message;
verifying the base station compression message for transmission with the verification compression message and determining the authenticity of the received navigation message; and
calculating the position of the positioning device (30, 30C1, 30C2) using a positioning signal in which the received navigation message is the true navigation message.