Receiving circuit, receiving method, and receiving device

Abstract

A receiving circuit according to the present disclosure comprises: a signal receiving unit that receives satellite signals in different frequency bands from the same satellite; a distance information acquiring unit that acquires distance information between a satellite position and a reception position on the basis of the satellite signals in different frequency bands received by the signal receiving unit; and a determining unit that compares the distance information of the different frequency bands acquired by the distance information acquiring unit to determine an irregularity of the satellite signal.

Description

Receiving circuit, receiving method and receiving device

[0001] The present disclosure relates to a receiving circuit, a receiving method, and a receiving device.

[0002] The Global Navigation Satellite System (GNSS) generally refers to a satellite positioning system. In a satellite positioning system, signals emitted from satellites are acquired by a receiver on the ground, and the received satellite signals are weak. Therefore, it is difficult for a receiver installed inside a building to receive the weak satellite signals.

[0003] Therefore, a repeater is placed inside the building. The repeater receives satellite signals using an antenna placed outside the building and re-emits the satellite signals toward the inside of the building. However, while there is no problem if the receiver receives only the satellite signals re-emitted from the repeater, if the receiver receives both satellite signals from the satellite and from the repeater, positioning is performed based on two satellite signals with different characteristics, which may adversely affect positioning. For example, Patent Document 1 describes a technology for detecting interference in a satellite positioning system.

[0004] Japanese Patent Application Laid-Open No. 2020-201073

[0005] The technology described in Patent Document 1 determines whether jamming signals are being received based on two satellite information sets generated from radio waves received by two types of antennas with different coverage areas. However, because the technology in Patent Document 1 compares pseudoranges between the same satellites, it requires the installation of two types of antennas with different directivities, which increases the cost of the device. Furthermore, the technology in Patent Document 1 is difficult to apply to wearable device products whose antenna orientations are not consistent. Furthermore, narrowing the antenna coverage area reduces the number of satellites available for positioning, which may affect high-precision positioning under jamming conditions.

[0006] Therefore, the present disclosure proposes a receiving circuit, a receiving method, and a receiving device that improve positioning accuracy.

[0007] In order to solve the above problems, one embodiment of a receiving circuit according to the present disclosure includes a signal receiving unit that receives each satellite signal of different frequency bands from the same satellite, a distance information acquisition unit that acquires distance information between the satellite position and the receiving position based on each satellite signal of different frequency bands received by the signal receiving unit, and a judgment unit that compares the distance information of different frequency bands acquired by the distance information acquisition unit to determine whether the satellite signal is fraudulent.

[0008] FIG. 1 is a diagram showing the current state of a positioning system. FIG. 2 is a diagram showing the basic configuration of a positioning system according to a first embodiment. FIG. 3 is a diagram showing an example of the configuration of a receiving device according to the first embodiment. FIG. 4 is a flowchart showing an example of processing in the receiving device according to the first embodiment. FIG. 4 is a diagram showing the basic configuration of a positioning system according to a second embodiment. FIG. 5 is a diagram showing an example of the configuration of a receiving device according to the second embodiment. FIG. 6 is a flowchart showing an example of processing in the receiving device according to the second embodiment. FIG. 7 is a hardware configuration diagram showing an example of a computer that realizes the functions of the positioning system.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same components are designated by the same reference numerals, and redundant description will be omitted.

[0010] The present disclosure will be described in the following order: 1. Overview 1-1. Current state of positioning systems 1-2. Issues with positioning systems 2. First embodiment 2-1. Basic configuration of positioning system 2-2. Configuration example of receiving device 2-3. Processing example of receiving device 3. Second embodiment 3-1. Basic configuration of positioning system 3-2. Configuration example of receiving device 3-3. Processing example of receiving device 4. Third embodiment 5. Other embodiments 6. Effects of receiving circuit, receiving method, and receiving device according to the present disclosure 7. Hardware configuration

[0011] (1. Overview) (1-1. Current Status of Positioning Systems) The current status of positioning systems will be described using Fig. 1. Fig. 1 is a diagram showing the current status of positioning systems.

[0012] 1, a satellite positioning system is provided with multiple (four in FIG. 1) satellites 100A, 100B, 100C, and 100D. The satellites 100A, 100B, 100C, and 100D emit satellite signals. A first receiving device 111 is disposed outside a building 101. The first receiving device 111 receives the satellite signals emitted by the multiple satellites 100A, 100B, 100C, and 100D and determines its current position.

[0013] Furthermore, a repeater (relay station) 112 is placed inside the building 101. An antenna 113 is placed outside the building 101 and connected to the repeater 112 via a cable 114. The repeater 112 re-radiates the satellite signals of the satellites 100A, 100B, 100C, and 100D received by the antenna 113 into the building 101.

[0014] The second receiving device 115 is placed inside the building 101. The second receiving device 115 receives satellite signals from the multiple satellites 100A, 100B, 100C, and 100D re-emitted by the repeater 112, and determines its current position.

[0015] (1-2. Issues with the Positioning System) The second receiving device 115 located inside the building 101 can accurately determine its current location by receiving the satellite signals of satellites 100A, 100B, 100C, and 100D re-emitted by the repeater 112. On the other hand, the first receiving device 111 located outside the building 101 will receive not only the satellite signals radiated by satellites 100A, 100B, 100C, and 100D, but also the re-emitted satellite signals of satellites 100A, 100B, 100C, and 100D re-emitted by the repeater 112, making it difficult to accurately determine its current location.

[0016] That is, the distance from the satellite signals of the satellites 100A, 100B, 100C, and 100D to the first receiving device 111 differs from the distance from the satellites 100A, 100B, 100C, and 100D to the first receiving device 111 for the satellite signals and the re-emitted satellite signals of the satellites 100A, 100B, 100C, and 100D. The re-emitted satellite signals have a delayed code phase relative to the satellite signals, increasing the distance. This results in an error between the position determined by the first receiving device 111 and its actual position.

[0017] (2. First Embodiment) (2-1. Basic Configuration of Positioning System) The basic configuration of the positioning system according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram showing the basic configuration of the positioning system according to the first embodiment.

[0018] 2, the positioning system 1 performs positioning using a plurality of satellites 100. Although only one satellite 100 is shown in FIG. 2, at least three, and preferably four or more, satellites 100 are required. The satellites 100 emit satellite signals in different frequency bands. In the first embodiment, the different frequency bands are described using, for example, L1 waves (1575.42 MHz) and L5 waves (1176.45 MHz), but the frequency bands are not limited to L1 waves and L5 waves, and may also be L2 waves (1227.60 MHz), for example.

[0019] The receiving device 10 is placed outside the building 101. The receiving device 10 is, for example, a mobile terminal such as a smartphone or a mobile phone. However, the receiving device 10 may be mounted on a moving object other than a mobile terminal. The moving object may be, for example, a car, a bicycle, a bus, a truck, a motorcycle, a train, etc.

[0020] The receiving device 10 has a first antenna 11 and a second antenna 12. The receiving device 10 can receive two types of satellite signals emitted by multiple satellites 100 using the first antenna 11 and the second antenna 12. That is, the receiving device 10 can receive satellite signals in the L1 frequency band (hereinafter referred to as L1 satellite signals) and satellite signals in the L5 frequency band (hereinafter referred to as L5 satellite signals), which are different frequency bands. That is, the receiving device 10 receives the L1 satellite signals using the first antenna 11 and receives the L5 satellite signals using the second antenna 12. The receiving device 10 performs positioning using the received L1 satellite signals and L5 satellite signals.

[0021] Furthermore, a repeater (relay station) 20 is placed inside the building 101. An external antenna 21 is placed outside the building 101 and connected to the repeater 20 via a cable 22. The repeater 20 has an internal antenna 23. The repeater 20 receives a satellite signal from the satellite 100 from the external antenna 21 via the cable 22 and re-radiates the satellite signal inside the building 101 using the internal antenna 23. In this example, the repeater 20 re-radiates the L1 satellite signal as a specific frequency band. However, the repeater 20 may also re-radiate an L5 satellite signal.

[0022] The receiving device 30 is disposed inside the building 101. The receiving device 30 is, for example, but not limited to, a mobile terminal such as a smartphone or a mobile phone. The receiving device 30 has an antenna 31. The receiving device 30 is capable of receiving the L1 satellite signal (or the L5 satellite signal) re-radiated by the repeater 20 using the antenna 31. The receiving device 30 performs positioning using the received L1 satellite signal (or the L5 satellite signal). However, it is not essential for the positioning system 1 to have the receiving device 30 disposed inside the building 101.

[0023] However, there is a risk that the L1 satellite signal re-emitted by repeater 20 may also be re-emitted outside building 101. As a result, receiving device 10 may receive not only the L1 satellite signal and L5 satellite signal from satellite 100, but also the L1 satellite signal (or L5 satellite signal) from repeater 20. When receiving device 10 receives the L1 satellite signal from satellite 100 and the L1 satellite signal from repeater 20, it will perform positioning using two types of L1 satellite signals with different characteristics, which may result in a decrease in positioning accuracy.

[0024] Therefore, in the first embodiment, when the receiving device 10 receives a satellite signal (L1 satellite signal or L5 satellite signal) of a frequency band that is re-radiated from the repeater 20 out of the received satellite signals of different frequency bands (L1 satellite signal and L5 satellite signal), the receiving device 10 performs positioning by excluding the satellite signal (L1 satellite signal or L5 satellite signal) of the frequency band that is affected by the re-radiated satellite signal from the repeater 20.

[0025] (2-2. Example of the configuration of the receiving device) An example of the configuration of the receiving device according to the first embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of the configuration of the receiving device according to the first embodiment.

[0026] 3 , the receiving device 10 of the first embodiment includes an antenna 50 and a receiving circuit 60. The antenna 50 has a first antenna 11 and a second antenna 12. The receiving circuit 60 has a first RF circuit (signal receiving unit) 61, a second RF circuit (signal receiving unit) 62, a signal processing circuit (signal receiving unit) 63, a pseudo-distance generating unit (distance information acquiring unit) 64, a determining unit 65, and a positioning unit 66.

[0027] The first antenna 11 is connected to a first RF circuit 61, and the second antenna 12 is connected to a second RF circuit 62. The first RF circuit 61 and the second RF circuit 62 are connected to a signal processing circuit 63. The signal processing circuit 63 is connected to a pseudo-distance generation unit 64, which is connected to a determination unit 65, which is connected to a positioning unit 66.

[0028] The first RF circuit 61 is a high-frequency circuit that processes an L1 satellite signal in a first frequency band received using the first antenna 11 and outputs the signal as a first RF signal to the signal processing circuit 63. The second RF circuit 62 is a high-frequency circuit that processes an L5 satellite signal in a second frequency band received using the second antenna 12 and outputs the signal as a second RF signal to the signal processing circuit 63.

[0029] The signal processing circuit 63 is a baseband processing circuit and includes a signal conversion unit that converts the first RF signal and the second RF signal into a baseband signal, a satellite signal acquisition unit that acquires a satellite signal from the baseband signal, and a satellite signal tracking unit that tracks the satellite signal.

[0030] The first RF circuit 61, the second RF circuit 62, and the signal processing circuit 63 function as a signal receiving unit and receive satellite signals in different frequency bands (L1, L5) from the same satellite. Specifically, the first RF circuit 61 and the signal processing circuit 63 function as a first receiving unit and receive and process a first satellite signal (L1 satellite signal) in the first frequency band (L1) from a specific satellite. The second RF circuit 62 and the signal processing circuit 63 function as a second receiving unit and receive and process a second satellite signal (L5 satellite signal) in the second frequency band (L5) from a specific satellite.

[0031] In the first embodiment, the repeater 20 (see FIG. 2 ) emits a first re-radiated satellite signal (L1 re-radiated satellite signal) in the first frequency band or a second re-radiated satellite signal (L5 re-radiated satellite signal) in the second frequency band. Therefore, the first RF circuit 61 and signal processing circuit 63 functioning as a first receiving unit may receive both the first satellite signal (L1 re-radiated satellite signal) emitted by the satellite 100 (see FIG. 2 ) and the first re-radiated satellite signal (L1 re-radiated satellite signal) re-radiated by the repeater 20. Furthermore, the second RF circuit 62 and signal processing circuit 63 functioning as a second receiving unit may receive both the second satellite signal (L5 satellite signal) emitted by the satellite 100 (see FIG. 2 ) and the second re-radiated satellite signal (L5 re-radiated satellite signal) re-radiated by the repeater 20.

[0032] The pseudo-distance generating unit 64 functions as a distance information acquiring unit, and acquires distance information between the satellite positions and the receiving position based on the satellite signals in the different frequency bands (L1, L5) received by the signal receiving unit.

[0033] Specifically, the pseudorange generator 64 generates pseudorange information as distance information based on the baseband signal processed by the signal processing circuit 63. That is, the pseudorange generator 64 calculates the pseudoranges of the L1 satellite signal and the L5 satellite signal in different frequency bands (L1, L5). Here, the pseudoranges are calculated based on, for example, the transmission time of the satellite signal and the reception time of the satellite signal.

[0034] The pseudorange generating unit 64 generates a pseudorange p as shown in the following equation based on the satellite signal transmission time ts obtained from the signal processing circuit 63 at a specific reception time tr. Note that the pseudorange p is expressed as follows: p=c×{(tr+δtr)-(ts+δts)}+C where c is the speed of light, δtr and δts are clock biases of the receiver / satellite, and C is a pseudorange correction amount that can be corrected by the receiver due to ionospheric and tropospheric delays.

[0035] Here, the delay due to multipath and the delay amount due to the repeater 20 are parameters that are difficult to correct in the receiver. Of these, the multipath has little effect on the repeater 20. Therefore, when the effect of the repeater 20 is superimposed on a specific frequency band, it is possible to determine the presence or absence of the repeater 20 from the pseudorange differences occurring between multiple frequency bands.

[0036] The determination unit 65 compares the distance information of the different frequency bands generated by the pseudo distance generation unit 64 to determine whether the satellite signal is fraudulent. Specifically, the determination unit 65 compares the first distance information (first pseudo distance) with the second distance information (second pseudo distance) to determine whether the satellite signal is fraudulent. That is, the determination unit 65 compares the first distance information (first pseudo distance) based on the first satellite signal (L1 satellite signal) in the first frequency band (L1) with the second distance information (second pseudo distance) based on the second satellite signal (L5 satellite signal) in the second frequency band (L5) to determine whether the satellite signal is fraudulent and whether a satellite signal is re-emitted from the repeater 20.

[0037] When the difference (deviation) between the first pseudorange and the second pseudorange exceeds a preset first determination value, the determination unit 65 determines that the satellite signals include re-emitted satellite signals from the repeater 20. Then, when the ratio of the total number of satellite signals whose difference (deviation) exceeds the first determination value to the total number of received satellite signals exceeds a preset second determination value, the determination unit 65 determines that the satellite signals are invalid.

[0038] That is, when the determination unit 65 receives both a satellite signal and a re-radiated satellite signal in the same frequency band, it determines that the satellite signal in the relevant frequency band includes a re-radiated satellite signal from the repeater 20, and determines that the signal is fraudulent.

[0039] The determination unit 65 receives a plurality of types of satellite signals in different frequency bands, and when the reliability of the received plurality of types of satellite signals is high, determines whether the satellite signals are fraudulent.

[0040] The positioning unit 66 performs positioning using satellite signals other than those in the frequency band that the determining unit 65 has determined to be fraudulent.

[0041] The pseudorange information used by the determination unit 65 may be the code phase. In other words, the pseudorange generation unit 64 may calculate the transmission time based on the code phase. When calculating the signal transmission time of each satellite, the sum of the satellite time information (on the order of seconds) contained in the satellite's navigation message, a hardware counter (which counts milliseconds or more), and the code phase is used. The distance a signal travels in 1 msec in a vacuum is approximately 300 km, and the delay caused by the repeater 20 is on the order of several hundred meters. Therefore, it is possible to use only the code phase for determination. Acquiring a navigation message with a GPS / L1CA signal takes at least six seconds, which delays the determination of the presence or absence of a repeater 20. However, using the code phase eliminates the need to acquire a navigation message, thereby enabling faster detection.

[0042] (2-3. Example of Processing in Receiving Device) An example of processing in the receiving device according to the first embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart showing an example of processing in the receiving device according to the first embodiment.

[0043] 3 and 4 , the first RF circuit 61 processes the L1 satellite signal in the first frequency band received by the first antenna 11 and outputs it as a first RF signal to the signal processing circuit 63, and the second RF circuit 62 processes the L5 satellite signal in the second frequency band received by the second antenna 12 and outputs it as a second RF signal to the signal processing circuit 63. In step S11, the signal processing circuit 63 starts sweeping the satellite signal being tracked that is included in a specific frequency band. In step S12, the signal processing circuit 63 determines whether or not it is receiving satellite signals in multiple different frequency bands from the same satellite 100. If the signal processing circuit 63 determines that it is not receiving satellite signals in multiple different frequency bands from the same satellite 100 (No), it returns to step S11.

[0044] On the other hand, if the signal processing circuit 63 determines that satellite signals in different frequency bands are being received from the same satellite 100 (Yes), then in step S13 the pseudorange generator 64 generates pseudoranges for each of the received satellite signals in the different frequency bands (L1, L5). In step S14, the pseudorange generator 64 determines whether each of the generated pseudoranges is reliable. Note that the reliability of the pseudoranges is determined, for example, by whether the radio wave intensity of the satellite signal is equal to or greater than a predetermined determination value. Here, if the pseudorange generator 64 determines that the pseudoranges are unreliable (No), the process returns to step S11.

[0045] On the other hand, if the pseudorange generator 64 determines that the pseudorange is reliable (Yes), it counts the total number of pairs of L1 and L5 satellite signals in different frequency bands (L1, L5) (L1L5_pair_cnt ＋＋) in steps S16 and S18, the decision unit 65 compares the first pseudorange with the second pseudorange. That is, in step S16, the decision unit 65 decides whether or not the difference obtained by subtracting the second pseudorange (pr_2) from the first pseudorange (pr_1) is greater than a preset first decision value (T_PR). Here, if the decision unit 65 decides that the difference obtained by subtracting the second pseudorange from the first pseudorange is greater than the first decision value (Yes), then in step S17, the decision unit 65 counts the total number of first pseudoranges whose difference is determined to be greater than the first decision value (illegal_pr_diff_cnt_1 ＋＋ ) and proceed to step S20.

[0046] On the other hand, if the decision unit 65 determines that the difference obtained by subtracting the second pseudorange from the first pseudorange is not greater than the first decision value (No), then in step S18 the decision unit 65 determines whether the difference obtained by subtracting the first pseudorange (pr_1) from the second pseudorange (pr_2) is greater than the first decision value (T_PR). If the decision unit 65 determines that the difference obtained by subtracting the first pseudorange from the second pseudorange is greater than the first decision value (Yes), then in step S19 the decision unit 65 counts the total number of second pseudoranges whose difference is determined to be greater than the first decision value (illegal_pr_diff_cnt_2 ＋＋ ) and proceeds to step S20. On the other hand, if the determination unit 65 determines that the difference obtained by subtracting the first pseudorange from the second pseudorange is not greater than the first determination value (No), the process proceeds to step S20 and the signal processing circuit 63 ends the sweep of the satellite signal being tracked.

[0047] When the determination unit 65 determines that the difference obtained by subtracting the second pseudorange from the first pseudorange is greater than the first determination value, it is determined that the L1 satellite signal that generated the first pseudorange includes an L1 re-emitted satellite signal, and the total number of such satellite signals is counted.On the other hand, when the determination unit 65 determines that the difference obtained by subtracting the first pseudorange from the second pseudorange is greater than the first determination value, it is determined that the L5 satellite signal that generated the second pseudorange includes an L5 re-emitted satellite signal, and the total number of such satellite signals is counted.

[0048] In step S21, the determination unit 65 determines whether the proportion of the total number of L1 satellite signals (illegal_pr_diff_cnt_1) whose difference exceeds the first determination value to the total number of received satellite signals (L1L5_pair_cnt) exceeds a predetermined second determination value (T_RATIO). If the determination unit 65 determines that the proportion of the total number of L1 satellite signals whose difference exceeds the first determination value to the total number of received satellite signals exceeds the second determination value (Yes), then in step S22, it determines that satellite signals in the first frequency band are being affected by the repeater 20.

[0049] On the other hand, if the determination unit 65 determines that the proportion of the total number of L1 satellite signals whose difference exceeds the first judgment value to the total number of received satellite signals does not exceed the second judgment value (No), then in step S23, the determination unit 65 determines whether the proportion of the total number of L5 satellite signals whose difference exceeds the first judgment value (illegal_pr_diff_cnt_2) to the total number of received satellite signals (L1L5_pair_cnt) exceeds the second judgment value (T_RATIO). Here, if the determination unit 65 determines that the proportion of the total number of L5 satellite signals whose difference exceeds the first judgment value to the total number of received satellite signals exceeds the second judgment value (Yes), then in step S24, the determination unit 65 determines that satellite signals in the second frequency band are being affected by the repeater 20. On the other hand, if the judgment unit 65 determines that the ratio of the total number of L5 satellite signals whose difference with respect to the total number of received satellite signals exceeds the first judgment value does not exceed the second judgment value (No), it proceeds to step S25.

[0050] Then, in step S25, the positioning unit 66 performs positioning using satellite signals in a frequency band that are not affected by the repeater 20 (e.g., L5 satellite signals), excluding satellite signals in a frequency band that are affected by the repeater 20 (e.g., L1 satellite signals).

[0051] (3. Second embodiment) (3-1. Basic configuration of positioning system) The basic configuration of a positioning system according to the second embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram showing the basic configuration of a positioning system according to the second embodiment. Note that components having the same functions as those in the first embodiment described above are given the same reference numerals, and detailed description thereof will be omitted.

[0052] 5, a positioning system 1A performs positioning using a plurality of satellites 100. The satellites 100 emit L1 satellite signals and L5 satellite signals in different frequency bands (L1, L5).

[0053] Receiving device 10A is placed outside building 101. Receiving device 10A has a first antenna 11 and a second antenna 12. Receiving device 10A is capable of receiving two types of L1 satellite signals and L5 satellite signals emitted by multiple satellites 100 using first antenna 11 and second antenna 12. In other words, receiving device 10A receives L1 satellite signals using first antenna 11 and L5 satellite signals using second antenna 12. Receiving device 10A performs positioning using the received L1 satellite signals and L5 satellite signals.

[0054] Repeater 20 is located inside building 101. Repeater 20 receives satellite signals from satellite 100 via cable 22 from external antenna 21 and re-radiates the satellite signals outside building 101 using internal antenna 23. Here, repeater 20 re-radiates both L1 and L5 satellite signals.

[0055] In the second embodiment, when the receiving device 10A receives satellite signals of different frequency bands (L1 satellite signals and L5 satellite signals) and receives a satellite signal of a frequency band that is re-radiated from the repeater 20 (L1 satellite signals or L5 satellite signals), the receiving device 10A performs positioning by excluding the satellite signals of the frequency band that are affected by the re-radiated satellite signals from the repeater 20 (L1 satellite signals or L5 satellite signals).

[0056] (3-2. Example of the configuration of the receiving device) An example of the configuration of the receiving device according to the second embodiment will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of the configuration of the receiving device according to the second embodiment.

[0057] 6 , a receiving device 10A according to the second embodiment includes an antenna 50 and a receiving circuit 60A. The antenna 50 includes a first antenna 11 and a second antenna 12. The receiving circuit 60A includes a first RF circuit 61, a second RF circuit 62, a signal processing circuit 63, a pseudo-distance generating unit 64, a geometric distance generating unit 67, a determining unit 65A, and a positioning unit 66.

[0058] The first RF circuit 61, the second RF circuit 62, and the signal processing circuit 63 have the same configuration as in the first embodiment, and a description thereof will be omitted.

[0059] In the second embodiment, the repeater 20 (see FIG. 5 ) emits both a first re-radiated satellite signal (L1 re-radiated satellite signal) in the first frequency band and a second re-radiated satellite signal (L5 re-radiated satellite signal) in the second frequency band. Therefore, the first RF circuit 61 and signal processing circuit 63 functioning as a first receiving unit may receive both the first satellite signal (L1 re-radiated satellite signal) emitted by the satellite 100 (see FIG. 5 ) and the first re-radiated satellite signal (L1 re-radiated satellite signal) re-radiated by the repeater 20. Furthermore, the second RF circuit 62 and signal processing circuit 63 functioning as a second receiving unit may receive both the second satellite signal (L5 satellite signal) emitted by the satellite 100 and the second re-radiated satellite signal (L5 re-radiated satellite signal) re-radiated by the repeater 20.

[0060] The pseudo-distance generator 64 generates pseudo-distance information as distance information based on the baseband signal processed by the signal processing circuit 63. That is, the pseudo-distance generator 64 calculates the pseudo-distances of the L1 satellite signal and the L5 satellite signal in different frequency bands (L1, L5).

[0061] The geometric distance generation unit 67 generates geometric distance information as distance information based on the baseband signal processed by the signal processing circuit 63. The geometric distance information is a physical geometric distance. That is, the pseudo-distance generation unit 64 calculates the geometric distance between the receiver 10A and a satellite 100 that outputs an L1 satellite signal and an L5 satellite signal in different frequency bands (L1, L5). The position of the satellite 100 is obtained from the navigation message (satellite signal) output by the satellite 100, and the position of the receiver 10A is obtained using the results of positioning calculations.

[0062] The determination unit 65A determines whether the satellite signal is fraudulent by comparing the distance information of different frequency bands generated by the pseudo distance generation unit 64. Specifically, the determination unit 65A compares the pseudo distance calculated by the pseudo distance generation unit 64 with the geometric distance calculated by the geometric distance generation unit 67 to determine whether the satellite signal is of a fraudulent frequency band.

[0063] That is, the determination unit 65A compares a first pseudorange based on a first satellite signal (L1 satellite signal) in the first frequency band (L1) with a first geometric distance between the satellite 100 that radiates the first satellite signal (L1 satellite signal) in the first frequency band (L1) and the receiving device 10A that receives the first satellite signal (L1 satellite signal), to determine whether or not a satellite signal is in an invalid frequency band, and determines whether or not a satellite signal is re-radiated from the repeater 20. The determination unit 65A also compares a second pseudorange based on a second satellite signal (L5 satellite signal) in the second frequency band (L5) with a second geometric distance between the satellite 100 that radiates the second satellite signal (L5 satellite signal) in the second frequency band (L5) and the receiving device 10A that receives the second satellite signal (L5 satellite signal), to determine whether or not a satellite signal is re-radiated from the repeater 20.

[0064] When the difference (deviation) between the pseudorange and the geometrical range exceeds a preset third determination value, the determination unit 65A determines that the satellite signals include re-emitted satellite signals from the repeater 20. Then, when the ratio of the total number of satellite signals whose difference (deviation) exceeds the third determination value to the total number of received satellite signals exceeds a preset second determination value, the determination unit 65A determines that the satellite signals are invalid.

[0065] That is, when the determination unit 65A receives both a satellite signal and a re-emitted satellite signal in the same frequency band, it determines that the satellite signals in the relevant frequency band include a re-emitted satellite signal from the repeater 20 and determines that the signal is fraudulent. The determination unit 65A determines whether or not both a satellite signal and a re-emitted satellite signal are being received for all received frequency bands.

[0066] The positioning unit 66 performs positioning using satellite signals other than those in the frequency band that the determining unit 65A has determined to be fraudulent.

[0067] (3-3. Example of Processing in Receiving Device) An example of processing in the receiving device according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of processing in the receiving device according to the second embodiment.

[0068] 6 and 7 , the first RF circuit 61 processes the L1 satellite signal in the first frequency band received by the first antenna 11 and outputs it as a first RF signal to the signal processing circuit 63, and the second RF circuit 62 processes the L5 satellite signal in the second frequency band received by the second antenna 12 and outputs it as a second RF signal to the signal processing circuit 63. In step S31, the signal processing circuit 63 begins sweeping the satellite signal being tracked that is included in a specific frequency band. Here, the processing from step S31 to step S35 is the same as the processing from step S11 to step S15 in the first embodiment, and therefore description thereof will be omitted.

[0069] In the process up to step S35, the pseudorange generating unit 64 generates a highly reliable pseudorange, and the total number of pairs of L1 satellite signals and L5 satellite signals in different frequency bands (L1, L5) is counted (L1L5_pair_cnt ＋＋ ), in step S36, the geometric distance generating unit 67 generates a geometric distance as geometric distance information based on the baseband signal processed by the signal processing circuit 63.

[0070] In step S37, the decision unit 65A compares the first pseudorange with the geometrical distance. That is, the decision unit 65A decides whether or not the difference obtained by subtracting the geometrical distance (gr) from the first pseudorange (pr_1) is greater than a preset third decision value (T_PR). Here, if the decision unit 65A decides that the difference obtained by subtracting the geometrical distance from the first pseudorange is greater than the third decision value (Yes), in step S38, the decision unit 65A counts the total number of first pseudoranges whose difference is determined to be greater than the third decision value (illegal_pr_diff_cnt_1 ＋＋ )do.

[0071] On the other hand, if the decision unit 65A determines that the difference obtained by subtracting the geometric distance from the first pseudorange is not greater than the third decision value (No), the process proceeds to step S39. In step S39, the decision unit 65A compares the second pseudorange with the geometric distance. That is, the decision unit 65A determines whether the difference obtained by subtracting the geometric distance (gr) from the second pseudorange (pr_2) is greater than the third decision value (T_PR). Here, if the decision unit 65A determines that the difference obtained by subtracting the geometric distance from the second pseudorange is greater than the third decision value (Yes), the decision unit 65A counts the total number of second pseudoranges whose difference is determined to be greater than the third decision value (illegal_pr_diff_cnt_2) in step S40. ＋＋ On the other hand, if the determination unit 65A determines that the difference obtained by subtracting the geometric distance from the second pseudorange is not greater than the third determination value (No), the process proceeds to step S41, and the signal processing circuit 63 ends the sweep of the satellite signal being tracked.

[0072] When the determination unit 65A determines that the difference obtained by subtracting the geometric distance from the first pseudo distance is greater than the third determination value, it is determined that the L1 satellite signal that generated the first pseudo distance includes an L1 re-emitted satellite signal, and the total number of such satellite signals is counted.On the other hand, when the determination unit 65A determines that the difference obtained by subtracting the geometric distance from the second pseudo distance is greater than the third determination value, it is determined that the L5 satellite signal that generated the second pseudo distance includes an L5 re-emitted satellite signal, and the total number of such satellite signals is counted.

[0073] In step S42, the determination unit 65A determines whether the proportion of the total number of L1 satellite signals (illegal_pr_diff_cnt_1) whose difference exceeds the third determination value to the total number of received satellite signals (L1L5_pair_cnt) exceeds a preset second determination value (T_RATIO). Here, if the determination unit 65A determines that the proportion of the total number of L1 satellite signals whose difference exceeds the third determination value to the total number of received satellite signals exceeds the second determination value (Yes), then in step S43, it determines that satellite signals in the first frequency band are being affected by the repeater 20.

[0074] On the other hand, if the determination unit 65A determines that the proportion of the total number of L1 satellite signals whose difference exceeds the third judgment value to the total number of received satellite signals does not exceed the second judgment value (No), the process proceeds to step S44. In step S44, the determination unit 65A determines whether the proportion of the total number of L5 satellite signals whose difference exceeds the third judgment value (illegal_pr_diff_cnt_2) to the total number of received satellite signals (L1L5_pair_cnt) exceeds the second judgment value (T_RATIO). Here, if the determination unit 65A determines that the proportion of the total number of L5 satellite signals whose difference exceeds the third judgment value to the total number of received satellite signals exceeds the second judgment value (Yes), the process proceeds to step S45, where the determination unit 65A determines that satellite signals in the second frequency band are being affected by the repeater 20. On the other hand, if the judgment unit 65A determines that the ratio of the total number of L5 satellite signals whose difference with respect to the total number of received satellite signals exceeds the third judgment value does not exceed the second judgment value (No), it proceeds to step S46.

[0075] Then, in step S46, the positioning unit 66 performs positioning using satellite signals in a frequency band that are not affected by the repeater 20 (e.g., L5 satellite signals), excluding satellite signals in a frequency band that are affected by the repeater 20 (e.g., L1 satellite signals).

[0076] 3 , the receiving circuit 60 of the receiving device 10 of the first embodiment has a first RF circuit 61, a second RF circuit 62, a signal processing circuit 63, a pseudo-range generator 64, a determiner 65, and a positioning unit 66. Here, the determiner 65 compares a first pseudo-range based on a first satellite signal (L1 satellite signal) in a first frequency band (L1) with a second pseudo-range based on a second satellite signal (L5 satellite signal) in a second frequency band (L5) to determine whether the satellite signal is in an invalid frequency band, and determines whether or not a satellite signal is being re-emitted from the repeater 20.

[0077] In the third embodiment, the determination unit 65 compares the first pseudorange with the second pseudorange and transmits information about satellite signals in an invalid frequency band as feedback to the signal processing unit (RF circuits 61, 62 and signal processing circuit 63). The signal processing circuit 63 then does not perform baseband processing on the satellite signals in the frequency band determined to be invalid. In other words, the signal processing circuit 63 performs baseband processing based on satellite signals excluding satellite signals in the frequency band determined to be invalid.

[0078] 6, the receiving circuit 60A of the receiving device 10A of the second embodiment has a first RF circuit 61, a second RF circuit 62, a signal processing circuit 63, a pseudo-distance generation unit 64, a geometrical distance generation unit 67, a determination unit 65A, and a positioning unit 66. The determination unit 65A compares the first pseudo-distance and the second pseudo-distance with the geometrical distance to determine whether a satellite signal of an invalid frequency band is present, and determines whether a satellite signal is being re-emitted from the repeater 20.

[0079] In the third embodiment, the determination unit 65A compares the first and second pseudoranges with the geometric distance to determine whether a satellite signal has an invalid frequency band, and transmits this information as feedback to the signal processing unit (RF circuits 61, 62 and signal processing circuit 63). The signal processing circuit 63 then does not perform baseband processing on the satellite signals with the frequency band determined to be invalid. In other words, the signal processing circuit 63 performs baseband processing based on satellite signals excluding satellite signals with the frequency band determined to be invalid.

[0080] (5. Other Embodiments) The processing according to the above-described embodiment may be implemented in various different forms other than the above-described embodiment.

[0081] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using known methods. In addition, the information including the processing procedures, specific names, various data, and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified. For example, the various information shown in each drawing is not limited to the information shown in the drawings.

[0082] Furthermore, the components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0083] Furthermore, the above-described embodiments can be combined as appropriate within the scope of not causing any contradiction in the processing content.

[0084] Although the above embodiment has been described using a repeater as an example, the present invention is not limited to repeaters. For example, the present invention may be used to detect jamming, which involves the emission of strong interference waves in the same frequency band as GNSS signals, or spoofing, which involves the emission of false GNSS signals by malicious individuals. The receiving circuit of this embodiment can detect abnormalities in distance information due to jamming or spoofing.

[0085] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0086] (6. Effects of the receiving circuit, receiving method, and receiving device according to the present disclosure) As described above, the receiving circuit according to the present disclosure comprises a signal receiving unit that receives each satellite signal of different frequency bands from the same satellite, a pseudo distance generation unit (distance information acquisition unit) 64 that acquires distance information between the satellite position and the receiving position based on each satellite signal of different frequency bands received by the signal receiving unit, and a judgment unit 65, 65A that compares the distance information of different frequency bands acquired by the pseudo distance generation unit 64 to determine whether the satellite signal is fraudulent.

[0087] Therefore, the pseudo-distance generator 64 acquires distance information between the satellite position and the receiving position based on satellite signals of different frequency bands from the same satellite, and the determination units 65 and 65A compare the distance information from the different frequency bands to determine whether the satellite signals are fraudulent. In this case, it is sufficient to install antennas that can receive satellite signals of different frequency bands from the same satellite, which can suppress increases in device costs. Furthermore, the number of satellite signals that the antenna can receive is not reduced, thereby improving positioning accuracy.

[0088] In the receiving circuit according to the present disclosure, the signal receiving unit has a first receiving unit that receives a first satellite signal in a first frequency band from a specific satellite and a second receiving unit that receives a second satellite signal in a second frequency band from the specific satellite, the pseudo-distance generating unit 64 acquires first distance information based on the first satellite signal and second distance information based on the second satellite signal, and the determining unit 65, 65A compares the first distance information with the second distance information to determine whether the satellite signal is in an invalid frequency band. Therefore, by comparing the first distance information with the second distance information to determine whether the satellite signal is in an invalid frequency band, it is possible to appropriately determine whether or not a satellite signal is being re-emitted from the repeater 20.

[0089] In the receiving circuit according to the present disclosure, the distance information includes pseudoranges, and therefore, by comparing the first pseudorange with the second pseudorange to determine whether a satellite signal in an invalid frequency band is present, it is possible to appropriately determine whether a satellite signal is re-emitted from the repeater 20.

[0090] In the receiver circuit according to the present disclosure, the pseudorange is calculated based on the time of transmission of the satellite signal and the time of reception of the satellite signal, so that the pseudorange can be calculated with high accuracy.

[0091] In the receiving circuit according to the present disclosure, the transmission time is calculated based on the code phase, which allows for faster processing.

[0092] In the receiving circuit according to the present disclosure, the determination unit 65 determines that the satellite signal is invalid when the deviation between the pseudoranges of different frequency bands exceeds a predetermined first determination value. Therefore, by comparing the deviation with the first determination value, it is possible to appropriately detect the presence or absence of a satellite signal being re-emitted from the repeater 20.

[0093] In the receiving circuit according to the present disclosure, the determining unit 65 determines that the satellite signals are invalid when the ratio of the total number of satellite signals received by the signal receiving unit whose deviation exceeds a first determination value exceeds a predetermined second determination value, thereby enabling appropriate detection of the presence or absence of re-emitted satellite signals from the repeater 20.

[0094] In the receiving circuit according to the present disclosure, the distance information includes a pseudo-range and reception position information, and the determination unit 65A compares the pseudo-range with the reception position information to determine whether a satellite signal of an invalid frequency band is present. Therefore, even if re-emitted satellite signals of multiple frequency bands are re-emitted from the repeater 20, the presence or absence of a re-emitted satellite signal from the repeater 20 can be properly detected.

[0095] In the receiving circuit according to the present disclosure, the reception position information includes the geometric distance between the satellite position and the reception position, so that the reception position information can be calculated with high accuracy.

[0096] In the receiving circuit according to the present disclosure, the determination unit 65A determines that the satellite signal is invalid if the deviation between the pseudorange and the geometric distance for a specific frequency band exceeds a preset third determination value. Therefore, by comparing the deviation with the third determination value, it is possible to appropriately detect the presence or absence of a satellite signal being re-emitted from the repeater 20.

[0097] In the receiving circuit according to the present disclosure, the determining unit 65A determines that the satellite signals are invalid when the ratio of the total number of satellite signals received by the signal receiving unit whose deviation exceeds a third determination value exceeds a preset second determination value, thereby enabling appropriate detection of the presence or absence of re-emitted satellite signals from the repeater 20.

[0098] In the receiving circuit according to the present disclosure, the signal receiving unit can receive multiple satellite signals in different frequency bands emitted from a specific satellite, as well as re-emitted satellite signals that are emitted from the specific satellite and then re-emitted. Therefore, the determining unit 65, 65A can appropriately detect the presence or absence of a re-emitted satellite signal from the repeater 20 by determining whether both the multiple satellite signals and the re-emitted satellite signal have been received.

[0099] In the receiving circuit according to the present disclosure, the signal receiving unit can receive multiple re-radiated satellite signals in different frequency bands that are re-radiated after being radiated from a specific satellite, so even if re-radiated satellite signals in multiple frequency bands are re-radiated from the repeater 20, it is possible to appropriately detect the presence or absence of a re-radiated satellite signal from the repeater 20.

[0100] In the receiving circuit according to the present disclosure, when the determination unit 65, 65A receives both a satellite signal and a re-emitted satellite signal in the same frequency band, it determines that the satellite signal in the corresponding frequency band is invalid, thereby enabling appropriate detection of the presence or absence of a re-emitted satellite signal from the repeater 20.

[0101] In the receiving circuit according to the present disclosure, the determination unit 65A determines whether or not both satellite signals and re-emitted satellite signals are being received for all frequency bands received by the signal receiving unit, thereby enabling appropriate detection of the presence or absence of re-emitted satellite signals from the repeater 20 for all frequency bands.

[0102] In the receiving circuit according to the present disclosure, the determination unit 65, 65A determines whether the satellite signals are fraudulent when the signal receiving unit receives multiple types of satellite signals in different frequency bands and the reliability of the received multiple types of satellite signals is high. This reduces false positives and missed detections in fraud determinations, thereby improving positioning accuracy.

[0103] In the receiving circuit according to the present disclosure, the signal receiving unit has a signal processing circuit 63 that performs baseband processing of satellite signals, and the determination unit 65, 65A transmits information about satellite signals in frequency bands determined to be fraudulent to the signal processing circuit 63, and the signal processing circuit 63 does not perform baseband processing on the satellite signals in frequency bands determined to be fraudulent. As a result, the signal processing circuit 63 performs baseband processing only on satellite signals in normal frequency bands, excluding satellite signals in frequency bands determined to be fraudulent, thereby improving positioning accuracy and reducing power consumption by eliminating unnecessary processing by the signal processing circuit 63.

[0104] The receiving circuit according to the present disclosure includes a positioning unit 66 that performs positioning using satellite signals other than those in frequency bands that have been determined to be invalid by the determination units 65 and 65A. As a result, the positioning unit 66 performs baseband processing using only satellite signals in normal frequency bands, thereby improving positioning accuracy.

[0105] The receiving method disclosed herein receives satellite signals of different frequency bands from the same satellite, obtains distance information between the satellite position and the receiving position based on the received satellite signals of different frequency bands, and compares the obtained distance information of the different frequency bands to determine whether the satellite signals are fraudulent.

[0106] Therefore, it is only necessary to install an antenna that can receive satellite signals of different frequency bands from the same satellite, which can suppress increases in device costs.In addition, the number of satellite signals that the antenna can receive does not decrease, and positioning accuracy can be improved.

[0107] The receiving device according to the present disclosure includes a plurality of antennas 50 capable of receiving satellite signals of different frequency bands, a signal receiving unit that receives each satellite signal of different frequency bands from the same satellite using the plurality of antennas 50, a pseudo-distance generating unit (distance information acquiring unit) 64 that acquires distance information between the satellite position and the receiving position based on each satellite signal of different frequency bands received by the signal receiving unit, and a determination unit 65, 65A that compares the distance information of different frequency bands acquired by the pseudo-distance generating unit 64 to determine whether the satellite signal is fraudulent.

[0108] Therefore, it is only necessary to install an antenna that can receive satellite signals of different frequency bands from the same satellite, which can suppress increases in device costs.In addition, the number of satellite signals that the antenna can receive does not decrease, and positioning accuracy can be improved.

[0109] (7. Hardware Configuration) FIG. 8 is a hardware configuration diagram showing an example of a computer that realizes the functions of the positioning system.

[0110] Information devices such as the positioning system 1 according to the embodiment described above are realized by, for example, a computer 1000 configured as shown in Fig. 8. The positioning system 1 according to the embodiment will be described below as an example. The computer 1000 includes a CPU 1100, a RAM 1200, a ROM (Read Only Memory) 1300, a HDD (Hard Disk Drive) 1400, a communication interface 1500, and an input / output interface 1600. The components of the computer 1000 are connected by a bus 1050.

[0111] The CPU 1100 operates and controls each component based on programs stored in the ROM 1300 or the HDD 1400. For example, the CPU 1100 loads the programs stored in the ROM 1300 or the HDD 1400 into the RAM 1200 and executes processing corresponding to the various programs.

[0112] The ROM 1300 stores boot programs such as a Basic Input Output System (BIOS) that is executed by the CPU 1100 when the computer 1000 is started, and programs that depend on the hardware of the computer 1000 .

[0113] HDD 1400 is a computer-readable recording medium that non-temporarily records programs executed by CPU 1100 and data used by such programs. Specifically, HDD 1400 is a recording medium that records a program for executing the receiving method according to the present disclosure, which is an example of program data 1450.

[0114] The communication interface 1500 is an interface for connecting the computer 1000 to an external network 1550 (e.g., the Internet). For example, the CPU 1100 receives data from other devices and transmits data generated by the CPU 1100 to other devices via the communication interface 1500.

[0115] The input / output interface 1600 is an interface for connecting the input / output device 1650 and the computer 1000. For example, the CPU 1100 receives data from an input device such as a keyboard or a mouse via the input / output interface 1600. The CPU 1100 also transmits data to an output device such as a display, a speaker, or a printer via the input / output interface 1600. The input / output interface 1600 may also function as a media interface for reading programs and the like recorded on a predetermined recording medium. Examples of media include optical recording media such as a DVD (Digital Versatile Disc) or a PD (Phase Change Rewritable Disc), magneto-optical recording media such as an MO (Magneto-Optical Disk), tape media, magnetic recording media, and semiconductor memories.

[0116] For example, when the computer 1000 functions as the positioning system 1 according to the embodiment, the CPU 1100 of the computer 1000 executes a program loaded onto the RAM 1200 to realize the functions of the receiving circuit 60, etc. Also, the HDD 1400 stores the program according to the present disclosure, etc. Note that the CPU 1100 reads and executes the program data 1450 from the HDD 1400, but as another example, the CPU 1100 may obtain these programs from another device via an external network 1550.

[0117] The present technology can also be configured as follows. (1) A receiving circuit including: a signal receiving unit that receives satellite signals of different frequency bands from the same satellite; a distance information acquisition unit that acquires distance information between a satellite position and a reception position based on the satellite signals of different frequency bands received by the signal receiving unit; and a determination unit that compares the distance information of the different frequency bands acquired by the distance information acquisition unit to determine whether the satellite signals are fraudulent. (2) The receiving circuit according to (1), wherein the signal receiving unit has a first receiving unit that receives a first satellite signal of a first frequency band from a specific satellite and a second receiving unit that receives a second satellite signal of a second frequency band from the specific satellite, the distance information acquisition unit acquires first distance information based on the first satellite signal and second distance information based on the second satellite signal, and the determination unit compares the first distance information with the second distance information to determine whether the satellite signal is of a fraudulent frequency band. (3) The receiving circuit according to (1) or (2), wherein the distance information includes a pseudorange. (4) The receiving circuit according to (3), wherein the pseudorange is calculated based on a transmission time of a satellite signal and a reception time of the satellite signal. (5) The receiving circuit according to (4), wherein the transmission time is calculated based on a code phase. (6) The receiving circuit according to any one of (3) to (5), wherein the determination unit determines that the satellite signal is fraudulent when a deviation between the pseudoranges of different frequency bands exceeds a predetermined first determination value. (7) The receiving circuit according to (6), wherein the determination unit determines that the satellite signal is fraudulent when a ratio of the total number of satellite signals whose deviation exceeds the first determination value to the total number of satellite signals received by the signal receiving unit exceeds a predetermined second determination value. (8) The receiving circuit according to any one of (1) to (7), wherein the distance information includes a pseudorange and reception position information, and the determination unit compares the pseudorange with the reception position information to determine that the satellite signal is of an fraudulent frequency band. (9) The receiving circuit according to (8), wherein the reception position information includes a geometric distance between a satellite position and a reception position.(10) The receiving circuit according to (9), wherein the determination unit determines that the satellite signal is fraudulent when a deviation between the pseudorange and the geometric distance in a specific frequency band exceeds a predetermined third determination value. (11) The receiving circuit according to (10), wherein the determination unit determines that the satellite signal is fraudulent when a ratio of the total number of satellite signals for which the deviation exceeds the third determination value to the total number of satellite signals received by the signal receiving unit exceeds a predetermined second determination value. (12) The receiving circuit according to any one of (1) to (9), wherein the signal receiving unit is capable of receiving multiple satellite signals of different frequency bands that are emitted from a specific satellite and re-radiated satellite signals that are emitted from the specific satellite and then re-radiated. (13) The receiving circuit according to (12), wherein the signal receiving unit is capable of receiving multiple re-radiated satellite signals of different frequency bands that are emitted from the specific satellite and then re-radiated. (14) The receiving circuit according to (12) or (13), wherein, when receiving both the satellite signal and the re-emitted satellite signal in the same frequency band, the determination unit determines that the satellite signal in the corresponding frequency band is fraudulent. (15) The receiving circuit according to (14), wherein the determination unit determines whether or not both the satellite signal and the re-emitted satellite signal are received for all frequency bands received by the signal receiving unit. (16) The receiving circuit according to any one of (1) to (15), wherein the determination unit determines that the satellite signal is fraudulent when the signal receiving unit receives multiple types of satellite signals in different frequency bands and the reliability of the received multiple types of satellite signals is high. (17) The receiving circuit according to any one of (1) to (16), wherein the signal receiving unit has a signal processing unit that performs baseband processing of the satellite signal, and the determination unit transmits information about the satellite signal in the frequency band determined to be fraudulent to the signal processing unit, and the signal processing unit does not perform baseband processing on the satellite signal in the frequency band determined to be fraudulent. (18) The receiving circuit according to any one of (1) to (17), further comprising: a positioning unit that performs positioning using a satellite signal other than the satellite signal in the frequency band that the determination unit has determined to be fraudulent.(19) A receiving method in which a computer receives each satellite signal of different frequency bands from the same satellite, acquires distance information between the satellite position and the reception position based on the received satellite signals of different frequency bands, and compares the acquired distance information of the different frequency bands to determine whether the satellite signals are fraudulent. (20) A receiving device comprising: a plurality of antennas capable of receiving each satellite signal of different frequency bands, a signal receiving unit that receives each satellite signal of different frequency bands from the same satellite using the plurality of antennas, a distance information acquisition unit that acquires distance information between the satellite position and the reception position based on the satellite signals of different frequency bands received by the signal receiving unit, and a determination unit that compares the distance information of the different frequency bands acquired by the distance information acquisition unit to determine whether the satellite signals are fraudulent.

[0118] REFERENCE SIGNS LIST 1, 1A Positioning system 10, 10A Receiving device 11 First antenna 12 Second antenna 20 Repeater 30 Receiving device 50 Antenna 60, 60A Receiving circuit 61 First RF circuit (signal receiving unit) 62 Second RF circuit (signal receiving unit) 63 Signal processing circuit (signal receiving unit) 64 Pseudo distance generating unit (distance information acquiring unit) 65, 65A Determination unit 66 Positioning unit 67 Geometric distance generating unit 100 Satellite

Claims

1. A receiving circuit comprising: a signal receiving unit that receives satellite signals of different frequency bands from the same satellite; a distance information acquiring unit that acquires distance information between the satellite position and the receiving position based on the satellite signals of different frequency bands received by the signal receiving unit; and a judgment unit that compares the distance information of different frequency bands acquired by the distance information acquiring unit to determine whether the satellite signals are fraudulent.

2. The receiving circuit of claim 1, wherein the signal receiving unit has a first receiving unit that receives a first satellite signal in a first frequency band from a specific satellite and a second receiving unit that receives a second satellite signal in a second frequency band from the specific satellite; the distance information acquisition unit acquires first distance information based on the first satellite signal and second distance information based on the second satellite signal; and the determination unit compares the first distance information with the second distance information to determine whether the satellite signal is in an invalid frequency band.

3. The receiving circuit of claim 1, wherein the distance information comprises a pseudorange.

4. The receiving circuit according to claim 3, wherein the pseudorange is calculated based on the time of transmission of the satellite signal and the time of reception of the satellite signal.

5. The receiving circuit according to claim 4, wherein the transmission time is calculated based on a code phase.

6. The receiving circuit according to claim 3, wherein the determining unit determines that the satellite signal is fraudulent when the deviation of the pseudoranges in different frequency bands exceeds a preset first determination value.

7. The receiving circuit according to claim 6, wherein the determination unit determines that the satellite signals are fraudulent when the ratio of the total number of satellite signals for which the deviation exceeds the first determination value to the total number of satellite signals received by the signal receiving unit exceeds a preset second determination value.

8. The receiving circuit according to claim 1, wherein the distance information includes a pseudo-range and reception position information, and the determining unit compares the pseudo-range with the reception position information to determine whether the satellite signal is in an invalid frequency band.

9. The receiving circuit according to claim 8, wherein the reception position information includes a geometric distance between a satellite position and the reception position.

10. The receiving circuit according to claim 9, wherein the determining unit determines that the satellite signal is fraudulent when the deviation between the pseudorange and the geometrical distance in a specific frequency band exceeds a third predetermined determination value.

11. The receiving circuit according to claim 10, wherein the determination unit determines that the satellite signals are fraudulent when the ratio of the total number of satellite signals for which the deviation exceeds the third determination value to the total number of satellite signals received by the signal receiving unit exceeds a preset second determination value.

12. The receiving circuit according to claim 1, wherein the signal receiving unit is capable of receiving a plurality of satellite signals in different frequency bands emitted from a specific satellite and a re-radiated satellite signal that has been emitted from the specific satellite and then re-radiated.

13. The receiving circuit according to claim 12, wherein the signal receiving section is capable of receiving a plurality of re-radiated satellite signals in different frequency bands that are re-radiated after being radiated from the particular satellite.

14. The receiving circuit according to claim 12, wherein when the determining unit receives both the satellite signal and the re-radiated satellite signal in the same frequency band, it determines that the satellite signal in the corresponding frequency band is fraudulent.

15. The receiving circuit according to claim 14, wherein the determining unit determines whether or not both the satellite signal and the re-radiated satellite signal are being received for all frequency bands received by the signal receiving unit.

16. The receiving circuit according to claim 1, wherein the determination unit determines whether the satellite signal is fraudulent when the signal receiving unit receives multiple types of satellite signals in different frequency bands and the reliability of the received multiple types of satellite signals is high.

17. The receiving circuit according to claim 1, wherein the signal receiving unit has a signal processing unit that performs baseband processing of satellite signals, the determination unit transmits information about satellite signals in a frequency band that has been determined to be fraudulent to the signal processing unit, and the signal processing unit does not perform baseband processing on satellite signals in a frequency band that has been determined to be fraudulent.

18. The receiving circuit according to claim 1, further comprising a positioning unit that performs positioning using satellite signals other than those in the frequency band determined by the determination unit to be fraudulent.

19. A receiving method in which a computer receives satellite signals of different frequency bands from the same satellite, obtains distance information between the satellite position and the receiving position based on the received satellite signals of different frequency bands, and compares the obtained distance information of different frequency bands to determine whether the satellite signals are fraudulent.

20. A receiving device comprising: a plurality of antennas capable of receiving satellite signals of different frequency bands; a signal receiving unit that receives each of the satellite signals of different frequency bands from the same satellite using the plurality of antennas; a distance information acquisition unit that acquires distance information between the satellite position and the receiving position based on each of the satellite signals of different frequency bands received by the signal receiving unit; and a judgment unit that compares the distance information of the different frequency bands acquired by the distance information acquisition unit to determine whether the satellite signal is fraudulent.

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