Positioning apparatus

Abstract

To provide a positioning device capable of synchronizing timing when two integrated circuits respectively receive satellite signals and extract baseband signals.SOLUTION: The first integrated circuit includes a first receiver that receives a first satellite signal and converts the first satellite signal into a first intermediate frequency signal, a first converter that converts the first intermediate frequency signal into a first baseband signal, and a first baseband processor that processes the first baseband signal, the second integrated circuit includes a second receiver that receives a second satellite signal and converts the first satellite signal into a second intermediate frequency signal, a second converter that converts the second intermediate frequency signal into a second baseband signal, and a first baseband processor that processes the first baseband signal, the first integration circuit transmits a synchronizing signal for synchronizing a first timing signals for controlling the first conversion section and a second timing signals for controlling the second conversion section of the second integration circuit with each other to the second integration circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a positioning device. [Background technology]

[0002] Patent Document 1 describes a satellite positioning signal receiving device that includes a GNSS receiving circuit that functions as a master and acquires L1 navigation data and satellite observation values, and a GNSS receiving circuit that functions as a slave and acquires L2 / L5 navigation data and satellite observation values; the PPS counter of the slave GNSS receiving circuit is reset at the rising edge of the 1 PPS output of the PPS counter of the master GNSS receiving circuit, thereby synchronizing both PPS counters and acquiring satellite observation values ​​of two frequencies at the same time; and the master GNSS receiving circuit performs positioning calculations using the L1 navigation data and satellite observation values ​​that it has acquired itself and the L2 / L5 navigation data and satellite observation values ​​transferred from the slave GNSS receiving circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 155703 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the satellite positioning signal receiving device described in Patent Document 1, in both GNSS receiving circuits, the timing at which the satellite processing units capture and track baseband signals, decode navigation data, and obtain satellite observation values ​​is synchronized, but the timing at which the satellite signals are received and the baseband signals are extracted is not synchronized. [Means for solving the problem]

[0005] One aspect of the positioning device according to the present invention is a first integrated circuit; a second integrated circuit; The first integrated circuit comprises: a first receiver that receives a first satellite signal transmitted from a satellite and converts the first satellite signal into a first intermediate frequency signal; a first conversion unit that converts the first intermediate frequency signal into a first baseband signal; a first baseband processing unit that processes the first baseband signal, The second integrated circuit comprises: a second receiving unit that receives a second satellite signal transmitted from the satellite and converts the second satellite signal into a second intermediate frequency signal; a second conversion unit that converts the second intermediate frequency signal into a second baseband signal; a second baseband processing unit that processes the second baseband signal, The first integrated circuit transmits a synchronization signal to the second integrated circuit to synchronize a first timing signal that controls the operation timing of the first conversion unit and a second timing signal that controls the operation timing of the second conversion unit of the second integrated circuit. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a positioning device according to an embodiment of the present invention. [Figure 2] A diagram showing the structure of an L1 band navigation message in GPS. [Figure 3] A diagram showing the structure of a navigation message in the L5 band in GPS. [Figure 4] 3 is a timing chart showing waveforms of various signals of the GNSS receiver IC 10. FIG. [Figure 5] FIG. 2 is a timing chart showing waveforms of various signals when it is assumed that the GNSS receiver IC 10 and the GNSS receiver IC 20 are not synchronized. [Figure 6] 3 is a timing chart showing waveforms of various signals of the GNSS receiver ICs 10 and 20. FIG. [Figure 7] FIG. 3 is a flowchart showing an example of a processing procedure of the GNSS reception IC 10. [Figure 8]FIG. 4 is a flowchart showing an example of a processing procedure of the GNSS reception IC 20. DETAILED DESCRIPTION OF THE INVENTION

[0007] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0008] 1. Embodiment 1-1.Configuration of positioning device 1 is a diagram showing an example of the configuration of a positioning device 1 according to this embodiment. As will be described in detail below, the positioning device 1 receives satellite signals transmitted from satellites 2 and performs positioning based on the received satellite signals.

[0009] As shown in Fig. 1, the positioning device 1 of this embodiment includes GNSS receiver ICs 10 and 20, antennas 11 and 21, a TCXO 30, power supply ICs 40 and 50, and a battery 60. However, the positioning device 1 may be configured by omitting or modifying some of the components shown in Fig. 1, or by adding other components. GNSS is an abbreviation for Global Navigation Satellite System. IC is an abbreviation for Integrated Circuit. TCXO is an abbreviation for Temperature Compensated Crystal Oscillator.

[0010] The GNSS receiver ICs 10 and 20 operate on power supplied from a battery 60 via power supply ICs 40 and 50, respectively. That is, the battery 60 is shared by the GNSS receiver ICs 10 and 20. The battery 60 may be a primary battery or a secondary battery. The power supply IC 40 converts the output voltage of the battery 60 to a predetermined DC voltage and outputs the DC voltage to the GNSS receiver IC 10 as a power supply voltage VDD1. The power supply IC 50 converts the output voltage of the battery 60 to a predetermined DC voltage and outputs the DC voltage to the GNSS receiver IC 20 as a power supply voltage VDD2. The GNSS receiver IC 10 operates based on the power supply voltage VDD1 and a ground voltage VSS1, and the GNSS receiver IC 20 operates based on the power supply voltage VDD2 and a ground voltage VSS2.

[0011] The antennas 11 and 21 are antennas that receive various radio waves including satellite signals transmitted from each of the multiple satellites 2, and are connected to the GNSS reception ICs 10 and 20, respectively. The GNSS reception ICs 10 and 20 receive the satellite signals transmitted from each of the multiple satellites 2 via the antennas 11 and 21, respectively, and perform predetermined arithmetic processing based on the received satellite signals.

[0012] Satellite 2 is an artificial satellite that orbits the Earth in a predetermined orbit and constitutes part of the GNSS. Examples of GNSS include GPS, QZSS, EGNOS, GLONASS, GALILEO, and BeiDou. GPS is an abbreviation for Global Positioning System. QZSS is an abbreviation for Quasi Zenith Satellite System. EGNOS is an abbreviation for European Geostationary Navigation Overlay Service. GLONASS is an abbreviation for Global Navigation Satellite System. The following description will be given taking as an example a case where the satellite system to which satellite 2 belongs is GPS.

[0013] Satellite 2 is the L1 band with a center frequency of 1.57542 GHz and the 1.22760 GHz band. Satellite signals are transmitted to the ground with navigation messages superimposed on radio waves in multiple frequency bands, including the L2 band, which has a central frequency. GPS has approximately 30 satellites 2, and in order to identify which satellite 2 transmitted the satellite signal, each satellite 2 superimposes a code consisting of a unique 1023-chip pattern onto the L1 band satellite signal. The L1 band code is called the C / A code, and each chip is either +1 or -1, making it appear like a random pattern and repeating every 1 ms. C / A is an abbreviation for Coarse / Acquisition Code.

[0014] In addition, some satellites 2 also transmit satellite signals to the ground that have navigation messages superimposed on L5 band radio waves centered at 1.17645 GHz. Each satellite 2 superimposes a code consisting of a unique pattern of 10230 chips onto the L5 band satellite signal. Like the C / A code, the L5 band code has each chip being either +1 or -1, and appears to be a random pattern that is repeated every 1 ms.

[0015] In this embodiment, the GNSS receiver IC 10 and the GNSS receiver IC 20 receive satellite signals in different frequency bands and perform arithmetic processing. For example, the frequency band of the satellite signals received by the GNSS receiver IC 20 may be lower than the frequency band of the satellite signals received by the GNSS receiver IC 10. In the following, it is assumed that the GNSS receiver IC 10 receives satellite signals in the L1 band, and the GNSS receiver IC 20 receives satellite signals in the L5 band, which is a frequency band lower than the L1 band. The GNSS receiver IC 10 can detect the C / A code superimposed on the L1 band satellite signal by correlating the satellite signal with the pattern of each C / A code. Furthermore, the GNSS receiver IC 20 can detect the code superimposed on the L5 band satellite signal by correlating the satellite signal with the pattern of each L5 band code.

[0016] The satellite signals transmitted by each satellite 2 contain orbital information indicating the position of each satellite 2 in its orbit. Each satellite 2 is also equipped with an atomic clock, and the satellite signals contain highly accurate time information measured by the atomic clock. Therefore, the positioning device 1 receives satellite signals from four or more satellites 2 through the cooperation of the GNSS receiver ICs 10 and 20, and performs positioning calculations using the orbital information and time information contained in each satellite signal, thereby obtaining accurate information on the position and time of the antennas 11 and 21, which are the reception points. Specifically, the positioning device 1 calculates the difference between the time of each satellite 2 and the time of the reception point using the orbital information contained in each satellite signal, calculates a pseudo-distance between each satellite 2 and the reception point based on the time difference, and then uses the pseudo-distance to formulate a four-dimensional equation with the three-dimensional position (x, y, z) of the reception point and the time t as four variables, and finds its solution.

[0017] In addition, the ground control segment measures the slight time error of the atomic clocks installed on each satellite 2, and the satellite signals also contain time correction parameters to correct this time error.By using these time correction parameters to correct the time at the receiving point, extremely accurate time information can be obtained.

[0018] Figure 2 is a diagram showing the structure of an L1 band navigation message. As shown in Figure 2, an L1 band navigation message is configured as data in units of main frames, each of which has a total of 1500 bits. Starting from the beginning, the main frame is divided into five subframes, numbered 1 to 5, each of which has 300 bits. Data for one subframe is transmitted from each satellite 2 in 6 seconds. Therefore, data for one mainframe is transmitted from each satellite 2 in 30 seconds.

[0019] The 300-bit data contained in each of the five subframes is divided into 1st to 10th words, with 30 bits per word. In each subframe, the first word is a TLM word and the second word is a HOW word. TLM is an abbreviation for Telemetry, and HOW is an abbreviation for Hand Over Word. Therefore, TLM words and HOW Words are transmitted from satellite 2 at 6 second intervals.

[0020] The TLM word includes preamble data, a TLM message, a reserved bit, and parity data.

[0021] The HOW word contains time information called TOW or Z count. TOW is an abbreviation for Time of Week. The Z count data indicates the elapsed time in seconds from midnight every Sunday and returns to 0 at midnight the following Sunday. In other words, the Z count data is information in seconds indicating each week from the beginning of the week, and is a number representing the elapsed time in 1.5-second increments. Here, the Z count data indicates the time information when the first bit of the next subframe data is transmitted. For example, the Z count data of the first subframe indicates the time information when the first bit of the second subframe is transmitted. The HOW word also contains a 3-bit ID code indicating the subframe ID. In other words, the HOW words of the first to fifth subframes contain ID codes of "001," "010," "011," "100," and "101," respectively. The time on satellite 2 can be calculated from the week number data contained in the first subframe and the HOW word contained in each subframe.

[0022] Words 3 through 10 of the first subframe contain satellite correction data such as the week number, satellite 2 status, and clock correction coefficient. In more detail, the week number and satellite 2 status are contained in word 3, and the clock correction coefficient is contained in words 8 through 10. Words 3 through 10 of each of the second and third subframes contain ephemeris parameters, which are detailed orbit information for satellite 2. Words 3 through 10 of each of the fourth and fifth subframes contain almanac parameters, which are approximate orbit information for all satellites 2. Therefore, satellite correction data, ephemeris parameters, and almanac parameters are transmitted from satellite 2 at 30-second intervals.

[0023] Figure 3 shows the structure of an L5 band navigation message. As shown in Figure 3, an L5 band navigation message is composed of data with 300-bit messages as one unit, and is transmitted every six seconds. The 300 bits of data that make up each message are composed of, from the beginning, an 8-bit preamble, a 6-bit satellite number PRN, a 6-bit message type ID, a 17-bit message TOW count, a 1-bit alert flag, 262 bits of message content, and a 24-bit CRC. CRC is an abbreviation for Cyclic Redundancy Check.

[0024] The message TOW count is a TOW count simplified to 17 bits and expressed in 6-second increments. The actual TOW count is displayed in seconds as the elapsed time from midnight every Sunday, and returns to 0 at midnight the following Sunday. In other words, the actual TOW count is information displayed in seconds for each week from the beginning of the week, and is a number that represents the elapsed time in 1.5-second increments. The message TOW count is a simplified 17-bit representation of the actual TOW count.

[0025] The message content varies depending on the message type ID, but includes information that is the same as or similar to the information contained in the L1 band navigation message.

[0026] Returning to the explanation of FIG. 1, the GNSS receiver IC 10 has a control terminal PC1, an input terminal PI1, and an output terminal PO1, and the GNSS receiver IC 20 has a control terminal PC2, an input terminal PI2, and an output terminal PO2. The control terminal PC1 is a terminal for setting the GNSS receiver IC 10 as a master or a slave; the GNSS receiver IC 10 is set as a master when the control terminal PC1 is at a high level, and as a slave when the control terminal PC1 is at a low level. The control terminal PC2 is a terminal for setting the GNSS receiver IC 20 as a master or a slave. The GNSS receiver IC 20 is set as the master when the control terminal PC2 is at a high level, and as the slave when the control terminal PC2 is at a low level. A high-level voltage is input to one of the control terminals PC1 and PC2, and a low-level voltage is input to the other. Therefore, one of the GNSS receiver ICs 10 and 20 is set as the master, and the other is set as the slave. In this embodiment, as shown in FIG. 1, a power supply voltage VDD1, which is a high-level voltage, is input to the control terminal PC1, and a ground voltage VSS2, which is a low-level voltage, is input to the control terminal PC2. Therefore, the GNSS receiver IC 10 is set as the master by the control terminal PC1, and the GNSS receiver IC 20 is set as the slave by the control terminal PC2.

[0027] In the positioning device 1 of this embodiment, the GNSS receiver IC 10 and the GNSS receiver IC 20 work together to perform positioning. Therefore, it is necessary to synchronize the arithmetic processing by the GNSS receiver IC 10 and the arithmetic processing by the GNSS receiver IC 20. Therefore, the master GNSS receiver IC 10 transmits a synchronization signal SyncO to the slave GNSS receiver IC 20 via the output terminal PO1. Thus, the output terminal PO1 is a terminal that outputs the synchronization signal SyncO to the outside of the GNSS receiver IC 10. The GNSS receiver IC 20 receives the synchronization signal SyncO as a synchronization signal SyncI2 via the input terminal PI2 and performs arithmetic processing in synchronization with the synchronization signal SyncI2. Thus, the input terminal PI2 is a terminal that inputs the synchronization signal SyncI2 from the outside of the GNSS receiver IC 20. Since the GNSS receiver IC 20 operates as a slave, there is no need to output the synchronization signal SyncO to the output terminal PO2, and the output terminal PO2 is an unused terminal.

[0028] Here, because the GNSS receiver IC 10 and the GNSS receiver IC 20 are mounted on a wiring board (not shown), a delay occurs when the synchronization signal SyncO propagates through the wiring connecting the output terminal PO1 of the GNSS receiver IC 10 and the input terminal PI2 of the GNSS receiver IC 20. This causes a time difference between the synchronization signals SyncO and SyncI2. Therefore, in this embodiment, the GNSS receiver IC 10 receives the synchronization signal SyncO as the synchronization signal SyncI1 via the input terminal PI1 and performs arithmetic processing in synchronization with the synchronization signal SyncI1. In this way, the input terminal PI1 is a terminal through which the synchronization signal SyncI1 is input from outside the GNSS receiver IC 10.

[0029] A delay occurs when the synchronization signal SyncO propagates through the wiring on the wiring board connecting the output terminal PO1 and input terminal PI1 of the GNSS receiver IC 10, resulting in a time difference between the synchronization signals SyncO and SyncI1. As a result, the time difference between the synchronization signals SyncI1 and SyncI2 becomes smaller, improving the accuracy of synchronization between the calculation processes by the GNSS receiver IC 10 and the GNSS receiver IC 20. The closer the time difference between the synchronization signals SyncO and SyncI1 is to zero, the higher the synchronization accuracy becomes. Therefore, it is preferable that the length of the wiring connecting the output terminal PO1 of the GNSS receiver IC 10 and the input terminal PI2 of the GNSS receiver IC 20 be equal to the length of the wiring connecting the output terminal PO1 of the GNSS receiver IC 10 and the input terminal PI1 of the GNSS receiver IC 10.

[0030] As shown in FIG. 1, the GNSS receiver IC 10 has an RF processing unit 12, a DDC 13, a downsampling unit 14, a baseband processing unit 15, a timing signal generating unit 16, and a CPU 17, and operates based on a clock signal CKI output from a TCXO 30. RF is an abbreviation for Radio Frequency. DDC is an abbreviation for Digital Down Converter. CPU is an abbreviation for Central Processing Unit. The frequency of the clock signal CKI is, for example, several tens of MHz. FIG. 4 is a timing chart showing waveforms of various signals of the GNSS receiver IC 10. The function and operation of each unit will be described below with reference to FIG. 4 as appropriate.

[0031] The CPU 17 determines whether the GNSS receiver IC 10 operates as a master or a slave based on the logic level of the signal input from the control terminal PC1. In this embodiment, a high-level voltage is input from the control terminal PC1, so the CPU 17 operates the GNSS receiver IC 10 as a master. Specifically, the CPU 17 controls the timing signal generator 16 to output a synchronization signal SyncO. The CPU 17 also operates as a master in communication with the CPU 27 of the GNSS receiver IC 20.

[0032] The timing signal generating unit 16 outputs a synchronization signal SyncO under the control of the CPU 17. As shown in Fig. 4, the synchronization signal SyncO is a signal that remains high for a certain period of time, is output to the outside from an output terminal PO1, and is input as a synchronization signal SyncI1 from an input terminal PI1. As shown in Fig. 4, the synchronization signal SyncI1 is a delayed version of the synchronization signal SyncO.

[0033] The timing signal generator 16 generates timing signals TXM1 and Tms1 in synchronization with the synchronization signal SyncI1. As shown in FIG. 4, the timing signal TXM1 is a signal that goes high for a fixed period at a predetermined cycle. The timing signal Tms1 is a signal that defines the timing of 1 ms and goes high for a fixed period every 1 ms. The timing signal generator 16 makes the timing signal Tms1 go high for a fixed period every time it counts M rising edges of the timing signal TXM1 using an internal counter (not shown). The timing signal TXM1 is input to the downsampling unit 14 and the baseband processor 15, and the timing signal Tms1 is input to the DDC 13.

[0034] The RF processing unit 12 receives L1-band satellite signals transmitted from each satellite 2 and converts the received satellite signals into intermediate frequency signals IF1. Specifically, the RF processing unit 12 extracts the L1-band satellite signals from the signals received by the antenna 11 using a bandpass filter, amplifies the extracted satellite signals using an LNA, and mixes the amplified signals with a clock signal obtained by multiplying the clock signal CKI using a PLL using a mixer, thereby downconverting the signals to intermediate frequency band signals of, for example, several MHz. LNA is an abbreviation for Low Noise Amplifier. PLL is an abbreviation for Phase Locked Loop. The RF processing unit 12 then amplifies and lowpass filters the intermediate frequency band signals, and then converts them into digital signals using an ADC. For example, the ADC performs A / D conversion on the intermediate frequency band signals at the cycle of the clock signal CKI and outputs a digital signal. This digital signal is input to the DDC 13 as the intermediate frequency signal IF1.

[0035] The DDC13 converts the intermediate frequency signal IF1 into a digital signal DC1 with a center frequency of 0 Hz in synchronization with the timing signal Tms1. Specifically, as shown in Figure 4, the DDC13 synchronizes with the timing signal Tms1 and begins generating a sine wave digital signal Sinw1, for example, at a frequency of several MHz. The sampling rate of the sine wave digital signal Sinw1 is the same as the center frequency of the intermediate frequency signal IF1. The DDC13 mixes the intermediate frequency signal IF1 with the sine wave digital signal Sinw1, then performs low-pass filtering to convert it into a digital signal DC1 with a center frequency of 0 Hz. The sampling rate of the digital signal DC1 matches the frequency of the clock signal CKI.

[0036] 4, the downsampling unit 14 downsamples the digital signal DC1 in response to the timing signal TXM1 and outputs a baseband signal BB1. The baseband signal BB1 is input to the baseband processing unit 15.

[0037] In this way, the DDC 13 and downsampling unit 14 function as a conversion unit 18 that converts the intermediate frequency signal IF1 into a baseband signal BB1. Therefore, the timing signals Tms1 and TXM1 are signals that control the operation timing of the conversion unit 18.

[0038] The baseband processor 15 processes the baseband signal BB1 in synchronization with the timing signal TXM1. Specifically, the baseband processor 15 generates local codes with the same pattern as each C / A code and performs a satellite search, which is a process of correlating each C / A code included in the baseband signal BB1 with the local code. Because satellite 2 moves at high speed, the frequency of the L1-band satellite signal received by the GNSS receiver IC 10 fluctuates within a range of approximately ±2 kHz from 1.57542 GHz due to the Doppler effect. Since the Doppler frequency, which is the frequency of this fluctuation, becomes a frequency offset of the satellite signal, the baseband processor 25 performs a satellite search taking the frequency offset of the satellite signal into account. Specifically, the baseband processor 15 adjusts the phase and chip rate of the local code so that the correlation value for each local code peaks. If the correlation value is equal to or greater than a threshold, the baseband processor 15 determines that it has synchronized with, or captured, satellite 2 whose C / A code is that local code.

[0039] Note that GPS employs a CDMA system in which all satellites 2 transmit satellite signals at the same frequency using different C / A codes. Therefore, the baseband processing unit 15 can search for satellites 2 that can be captured by determining the C / A codes contained in the received satellite signals. CDMA is an abbreviation for Code Division Multiple Access.

[0040] When the baseband processing unit 15 acquires a satellite 2 based on the baseband signal BB1, it calculates the frequency offset of the satellite signal based on the chip rate, calculates the code phase based on the phase of the local code, and generates satellite acquisition information including the frequency offset and code phase of the satellite signal. In this embodiment, the baseband processing unit 15 does not perform positioning calculations, and the GNSS reception IC 20 performs positioning calculations using the satellite acquisition information generated by the baseband processing unit 15. Therefore, the GNSS reception IC 10 transmits the satellite acquisition information generated by the baseband processing unit 15 to the GNSS reception IC 20. Specifically, the CPU 17 of the GNSS reception IC 10 acquires the satellite acquisition information generated by the baseband processing unit 15 and transmits the acquired satellite acquisition information to the CPU 27 of the GNSS reception IC 20.

[0041] 1, the GNSS receiver IC 20 has the same configuration as the GNSS receiver IC 10, and includes an RF processing unit 22, a DDC 23, a downsampling unit 24, a baseband processing unit 25, a timing signal generating unit 26, and a CPU 27, and operates based on a clock signal CKI output from the TCXO 30. The names of the various signals of the GNSS receiver IC 20 are different from but similar to the names of the various signals of the GNSS receiver IC 10, and the timing chart showing the waveforms of the various signals of the GNSS receiver IC 20 is the same as that of Fig. 4, so it is not shown in the figure.

[0042] The CPU 27 determines whether to operate the GNSS receiver IC 20 as a master or a slave based on the logic level of the signal input from the control terminal PC2. In this embodiment, since a low-level voltage is input from the control terminal PC2, the CPU 27 operates the GNSS receiver IC 20 as a slave. Specifically, the CPU 27 controls the timing signal generator 26 to receive the synchronization signal SyncO as the synchronization signal SyncI2. The CPU 27 also operates as a slave in communication with the CPU 17 of the GNSS receiver IC 10.

[0043] The synchronization signal SyncO output by the timing signal generation unit 16 of the GNSS receiver IC 10 is input as the synchronization signal SyncI2 from the input terminal PI2 of the GNSS receiver IC 20. The synchronization signal SyncI2 is a delayed version of the synchronization signal SyncO, and is a signal that goes high for a certain period of time at approximately the same timing as the synchronization signal SyncI1 shown in Figure 4.

[0044] The timing signal generator 26 generates timing signals TXM2 and Tms2 in synchronization with the synchronization signal SyncI2. The timing signal TXM2 is at a high level for a certain period at a predetermined cycle. The timing signal Tms2 is a signal that defines the timing of 1 ms, and goes high for a fixed period every 1 ms. The timing signal generator 26 makes the timing signal Tms2 go high for a fixed period every time it counts N rising edges of the timing signal TXM2 using an internal counter (not shown). The timing signal TXM2 is input to the downsampling unit 24 and baseband processor 25, and the timing signal Tms2 is input to the DDC 23.

[0045] The RF processing unit 22 receives L5-band satellite signals transmitted from each satellite 2 and converts the received satellite signals into intermediate frequency signals IF2. Specifically, the RF processing unit 22 extracts the L5-band satellite signals from the signals received by the antenna 21 using a bandpass filter, amplifies the extracted satellite signals using an LNA, and mixes the amplified signals with a clock signal obtained by multiplying the clock signal CKI using a PLL using a mixer, thereby down-converting the signals to intermediate frequency band signals of, for example, several tens of megahertz. The RF processing unit 22 then amplifies and low-pass filters the intermediate frequency band signals, and then converts them into digital signals using an ADC. For example, the ADC performs A / D conversion on the intermediate frequency band signals at the cycle of the clock signal CKI and outputs digital signals. This digital signal is input to the DDC 23 as the intermediate frequency signal IF2.

[0046] The DDC23 converts the intermediate frequency signal IF2 into a digital signal DC2 with a center frequency of 0 Hz in synchronization with the timing signal Tms2. Specifically, the DDC23 begins generating a sine wave digital signal Sinw2, for example, at a frequency of several tens of MHz, in synchronization with the timing signal Tms2. The sampling rate of the sine wave digital signal Sinw2 is the same as the center frequency of the intermediate frequency signal IF2. The DDC23 mixes the intermediate frequency signal IF2 with the sine wave digital signal Sinw2, then performs low-pass filtering to convert it into a digital signal DC2 with a center frequency of 0 Hz. The sampling rate of the digital signal DC2 matches the frequency of the clock signal CKI.

[0047] The downsampling unit 24 downsamples the digital signal DC2 in response to the timing signal TXM2 and outputs a baseband signal BB2. The baseband signal BB2 is input to the baseband processing unit 25.

[0048] In this way, the DDC 23 and downsampling unit 24 function as a conversion unit that converts the intermediate frequency signal IF2 into a baseband signal BB2. Therefore, the timing signals Tms2 and TXM2 are signals that control the operation timing of the conversion unit .

[0049] The baseband processor 25 processes the baseband signal BB2 in synchronization with the timing signal TXM2. Specifically, the baseband processor 25 generates local codes with the same pattern as each L5-band code and performs a satellite search, which is a process of correlating each code included in the baseband signal BB2 with the local code. Because satellite 2 moves at high speed, the frequency of the L5-band satellite signal received by the GNSS receiver IC 10 fluctuates within a range of approximately ±2 kHz from 1.17645 GHz due to the Doppler effect. Since the Doppler frequency, which is the frequency of this fluctuation, is a frequency offset of the satellite signal, the baseband processor 25 also takes the frequency offset of the satellite signal into account when performing a satellite search. Specifically, the baseband processor 25 adjusts the phase and chip rate of the local code so that the correlation value for each local code peaks. If the correlation value is equal to or greater than a threshold, the baseband processor 25 determines that it has synchronized with satellite 2, i.e., has captured satellite 2, for which the local code is an L5-band code.

[0050] When the baseband processing unit 25 captures the satellite 2 based on the baseband signal BB2, it calculates the frequency offset of the satellite signal based on the chip rate, calculates the code phase based on the phase of the local code, and generates a signal including the frequency offset and code phase of the satellite signal. The GNSS receiver IC 10 generates satellite capture information. In this embodiment, the CPU 27 acquires the satellite capture information generated by the baseband processing unit 15 of the GNSS receiver IC 10 and outputs the acquired satellite capture information to the baseband processing unit 25. When four or more satellites 2 are captured, the baseband processing unit 25 demodulates the navigation messages superimposed on the satellite signals transmitted from each satellite 2 based on the satellite capture information generated by itself and the satellite capture information generated by the baseband processing unit 15, and performs positioning calculations. Specifically, the baseband processing unit 25 mixes a local code having the same pattern as the L5 band code of each captured satellite 2 with the baseband signal BB2 at an appropriate timing based on the frequency offset and code phase of the satellite signal included in each satellite capture information, and demodulates the navigation messages including orbit information and time information of each satellite 2. The baseband processing unit 25 then performs positioning using a known method using the orbit information and time information of four or more satellites 2. The CPU 17 of the GNSS receiver IC 10 may obtain information on the positioning result by the baseband processing unit 25 via the CPU 27 of the GNSS receiver IC 20.

[0051] As described above, in this embodiment, the GNSS receiver IC 10 performs arithmetic processing on L1-band satellite signals, and the GNSS receiver IC 20 performs arithmetic processing on L5-band satellite signals. Because the chip rate of the L5-band code is 10 times that of the L1-band code, the accuracy of satellite capture by the baseband processing unit 25 is higher than that of the baseband processing unit 15. However, the computational load of satellite capture by the baseband processing unit 25 is greater than that of the baseband processing unit 25. Therefore, the GNSS receiver IC 20 receives satellite capture information generated by the baseband processing unit 15 of the GNSS receiver IC 10. The baseband processing unit 25 demodulates the navigation message included in the baseband signal BB2 based on the received satellite capture information, and performs positioning based on the demodulated navigation message. Therefore, the baseband processing unit 25 only needs to perform the minimum necessary satellite capture, reducing the computational load of satellite capture. As a result, the power consumption of the positioning device 1 is reduced, and the battery life of the battery 60 is extended.

[0052] However, if the GNSS receiver ICs 10 and 20 each start their arithmetic processing at an arbitrary timing, for example, as shown in FIG. 5, the time t1 when the timing signal Tms1 rises and the time t2 when the timing signal Tms2 rises will not coincide, and the data update timing of the baseband signal BB1 will not coincide with the data update timing of the baseband signal BB2. Therefore, the baseband processing unit 25 will not be able to correctly demodulate the navigation message superimposed on the baseband signal BB2 using the satellite acquisition information generated by the baseband processing unit 15 based on the baseband signal BB1. In other words, to enable the baseband processing unit 25 to demodulate the navigation message based on the satellite acquisition information generated by the baseband processing unit 15, the arithmetic processing of the GNSS receiver IC 10 and the arithmetic processing of the GNSS receiver IC 20 must be synchronized.

[0053] Therefore, in this embodiment, as shown in Figure 6, the GNSS receiver IC 10 outputs a synchronization signal SyncO, and the GNSS receiver ICs 10 and 20 start their calculation processes based on synchronization signals SyncI1 and SyncI2, which are respectively generated by delaying the synchronization signal SyncO. As a result, the timing signals Tms1 and Tms2 rise at the same time t1, so that the data update timing of the baseband signal BB1 and the data update timing of the baseband signal BB2 coincide. Therefore, the baseband processor 25 can correctly demodulate the navigation message superimposed on the baseband signal BB2 using the satellite capture information generated by the baseband processor 15 based on the baseband signal BB1.

[0054] As shown in Figure 1, the GNSS receiver IC 10 and the GNSS receiver IC 20 are integrated circuits with the same configuration, and the frequency band of the satellite signals to be received can be set arbitrarily for each. The GNSS receiver IC 10 may be set to receive satellite signals in the L1 band, and the GNSS receiver IC 20 may be set to receive satellite signals in the L5 band. If the GNSS reception ICs 10, 20 are integrated circuits with the same configuration, the development man-hours for the GNSS reception ICs 10, 20 are reduced. However, the GNSS reception IC 10 and the GNSS reception IC 20 do not have to be integrated circuits with the same configuration; the GNSS reception IC 10 may be configured specifically for receiving satellite signals in the L1 band, and the GNSS reception IC 20 may be configured specifically for receiving satellite signals in the L5 band. In this way, if the GNSS reception ICs 10, 20 are each integrated circuits configured specifically for receiving satellite signals in a predetermined frequency band, the size of each integrated circuit is reduced.

[0055] The GNSS receiver IC 10 is an example of a "first integrated circuit," and the GNSS receiver IC 20 is an example of a "second integrated circuit." The RF processing unit 12 is an example of a "first receiver," and the RF processing unit 22 is an example of a "second receiver." The conversion unit 18 is an example of a "first conversion unit," and the conversion unit 28 is an example of a "second conversion unit." The baseband processing unit 15 is an example of a "first baseband processing unit," and the baseband processing unit 25 is an example of a "second baseband processing unit." The output terminal PO1 is an example of a "first output terminal," the input terminal PI1 is an example of a "first input terminal," and the input terminal PI2 is an example of a "second input terminal." The control terminal PC1 is an example of a "first control terminal," and the control terminal PC2 is an example of a "second control terminal." The L1-band satellite signal received by the GNSS receiver IC 10 is an example of a "first satellite signal," and the L5-band satellite signal received by the GNSS receiver IC 20 is an example of a "second satellite signal." The intermediate frequency signal IF1 is an example of a "first intermediate frequency signal," and the intermediate frequency signal IF2 is an example of a "second intermediate frequency signal." The baseband signal BB1 is an example of a "first baseband signal," and the baseband signal BB2 is an example of a "second baseband signal." The timing signal Tms1 is an example of a "first timing signal," and the timing signal Tms2 is an example of a "second timing signal." The timing signal TXM1 is another example of a "first timing signal," and the timing signal TXM2 is another example of a "second timing signal."

[0056] 1-2. Positioning device processing procedure Fig. 7 is a flowchart showing an example of the procedure of processing performed by the GNSS receiver IC 10. As shown in Fig. 7, first, in step S10, the CPU 17 of the GNSS receiver IC 10 instructs the GNSS receiver IC 20 to start positioning. Next, in step S20, the timing signal generator 16 of the GNSS receiver IC 10 transmits a synchronization signal SyncO.

[0057] Next, in step S30, when the timing signal generation unit 16 receives the synchronization signal SyncI1, in step S40 the conversion unit 18 of the GNSS receiver IC 10 starts converting the intermediate frequency signal IF1 output from the RF processing unit 12 into a baseband signal BB1 in synchronization with the timing signals Tms1, TXM1 based on the synchronization signal SyncI1. Also, in step S50, the baseband processing unit 15 of the GNSS receiver IC 10 starts capturing the satellite 2 in synchronization with the timing signal TXM1.

[0058] Then, in step S80, until positioning by the positioning device 1 is completed, in step S60, each time the baseband processing unit 15 captures a satellite 2, in step S70 the CPU 17 of the GNSS receiving IC 10 transmits the satellite capture information generated by the baseband processing unit 15 to the CPU 27 of the GNSS receiving IC 20.

[0059] Finally, in step S80, if positioning by the positioning device 1 is to be ended, in step S90, the CPU 17 instructs the CPU 27 of the GNSS receiver IC 20 to end positioning, and the processing of the GNSS receiver IC 10 ends.

[0060] 8 is a flowchart showing an example of the procedure of the processing performed by the GNSS receiver IC 20. As shown in FIG. 8, first, in step S210, the CPU 27 of the GNSS receiver IC 20 waits until it receives an instruction to start positioning from the CPU 17 of the GNSS receiver IC 10, and then starts positioning. If this instruction is given, in step S220, the timing signal generating unit 26 of the GNSS receiver IC 20 waits until it receives the synchronization signal SyncI2.

[0061] Then, in step S220, when the timing signal generation unit 26 receives the synchronization signal SyncI2, in step S230 the conversion unit 28 of the GNSS receiver IC 20 starts converting the intermediate frequency signal IF2 output from the RF processing unit 22 into a baseband signal BB2 in synchronization with the timing signals Tms2, TXM2 based on the synchronization signal SyncI2. Also, in step S240, the baseband processing unit 25 of the GNSS receiver IC 20 starts capturing the satellite 2 in synchronization with the timing signal TXM2.

[0062] Then, in step S310, until the CPU 27 receives an instruction to end positioning from the CPU 17, the baseband processing unit 25 updates the number of captured satellites 2 in step S260 every time a satellite 2 is captured in step S250. Furthermore, in step S270, every time the CPU 27 receives satellite capture information from the CPU 17 of the GNSS receiver IC 10, the baseband processing unit 25 updates the number of captured satellites 2 in step S280. Furthermore, if the number of captured satellites 2 is four or more in step S290, the baseband processing unit 25 calculates the position of the positioning device 1 based on the satellite capture information of the four or more captured satellites 2 in step S300.

[0063] Finally, in step S310, when the CPU 27 receives an instruction to end positioning from the CPU 17, the processing of the GNSS reception IC 20 ends.

[0064] 1-3.Effects As described above, according to the positioning device 1 of this embodiment, the synchronization signal SyncO output from the GNSS receiver IC 10 can synchronize the timing at which the GNSS receiver IC 10 receives an L1-band satellite signal and extracts a baseband signal BB1 with the timing at which the GNSS receiver IC 20 receives an L5-band satellite signal and extracts a baseband signal BB2. Specifically, the synchronization signals SyncI1 and SyncI2, which are delayed versions of the synchronization signal SyncO, can synchronize the timing at which the converter 18 converts the intermediate frequency signal IF1 output from the RF processing unit 12 into a baseband signal BB1 with the timing at which the converter 28 converts the intermediate frequency signal IF2 output from the RF processing unit 22 into a baseband signal BB2. Therefore, according to the positioning device 1 of this embodiment, the GNSS receiver IC 10 and the GNSS receiver IC 20 work together to efficiently search for each satellite 2, thereby saving power and reducing the search time.

[0065] Furthermore, according to the positioning device 1 of this embodiment, by making the length of the wiring connecting the output terminal PO1 of the GNSS receiver IC 10 and the input terminal PI2 of the GNSS receiver IC 10 equal to the length of the wiring connecting the output terminal PO1 and the input terminal PI1 of the GNSS receiver IC 10, it is possible to align the time from when the synchronization signal SyncO is output from the output terminal PO1 to when it is input to the input terminals PI1 and PI2, thereby more accurately synchronizing the operation timing of the conversion unit 18 and the operation timing of the conversion unit 28.

[0066] Furthermore, according to the positioning device 1 of this embodiment, the GNSS reception IC 10 that receives satellite signals in the L1 band becomes the master, and the GNSS reception IC 20 that receives satellite signals in the L5 band becomes the slave, and they receive satellite signals in different frequency bands to efficiently capture satellite 2, and the GNSS reception IC 20 can perform positioning in a short time by using the satellite capture information generated by the GNSS reception IC 10.

[0067] 2. Variations The present invention is not limited to the present embodiment, and various modifications can be made within the scope of the present invention. do.

[0068] For example, in the above embodiment, the GNSS reception IC 10 performs arithmetic processing on L1-band satellite signals, and the GNSS reception IC 20 performs arithmetic processing on L5-band satellite signals, but this is not limited to the frequency bands of satellite signals that are the subject of arithmetic processing by the GNSS reception ICs 10 and 20. For example, the GNSS reception IC 10 may perform arithmetic processing on L1-band satellite signals, and the GNSS reception IC 20 may perform arithmetic processing on L2-band satellite signals, or the GNSS reception ICs 10 and 20 may perform arithmetic processing on satellite signals in the same frequency band.

[0069] Furthermore, in the above embodiment, the GNSS receiver IC 20 performs the positioning calculation, but the positioning calculation may also be performed by the GNSS receiver IC 10. In this case, the GNSS receiver IC 10 may receive satellite capture information generated by the baseband processing unit 25 of the GNSS receiver IC 20, and the baseband processing unit 15 may demodulate the navigation message included in the baseband signal BB1 based on the received satellite capture information, and perform positioning based on the demodulated navigation message.

[0070] Furthermore, in the above embodiment, the GNSS reception IC 10 is the master and the GNSS reception IC 20 is the slave. However, the GNSS reception IC 20 may be the master and the GNSS reception IC 10 may be the slave. That is, the control terminal PC1 of the GNSS reception IC 10 may be at low level and the control terminal PC2 of the GNSS reception IC 20 may be at high level. In this case, the GNSS reception IC 20 outputs a synchronization signal SyncO from the output terminal PO2, and the synchronization signal SyncO is input to the input terminal PI1 of the GNSS reception IC 10 and the input terminal PI2 of the GNSS reception IC 20. Furthermore, in communication between the CPU 17 of the GNSS reception IC 10 and the CPU 27 of the GNSS reception IC 20, the CPU 27 operates as the master and the CPU 17 operates as the slave.

[0071] The above-described embodiments and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0072] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0073] The following can be derived from the above-described embodiment and modifications.

[0074] One aspect of the positioning device is a first integrated circuit; a second integrated circuit; The first integrated circuit comprises: a first receiver that receives a first satellite signal transmitted from a satellite and converts the first satellite signal into a first intermediate frequency signal; a first conversion unit that converts the first intermediate frequency signal into a first baseband signal; a first baseband processing unit that processes the first baseband signal, The second integrated circuit comprises: a second receiving unit that receives a second satellite signal transmitted from the satellite and converts the second satellite signal into a second intermediate frequency signal; a second conversion unit that converts the second intermediate frequency signal into a second baseband signal; a second baseband processing unit that processes the second baseband signal, The first integrated circuit transmits a synchronization signal to the second integrated circuit to synchronize a first timing signal that controls the operation timing of the first conversion unit and a second timing signal that controls the operation timing of the second conversion unit of the second integrated circuit.

[0075] According to this positioning device, the synchronization signal can synchronize the timing at which the first integrated circuit receives the first satellite signal and extracts the first baseband signal with the timing at which the second integrated circuit receives the second satellite signal and extracts the second baseband signal. Therefore, according to this positioning device, the first integrated circuit and the second integrated circuit can work together to efficiently search for satellites, thereby saving power and reducing the time required for the search.

[0076] In one aspect of the positioning device, the first integrated circuit has a first output terminal that outputs the synchronization signal to an external device and a first input terminal that receives the synchronization signal from an external device; the second integrated circuit has a second input terminal to which the synchronization signal is input from an external device; The length of the wiring connecting the first output terminal and the second input terminal may be equal to the length of the wiring connecting the first output terminal and the first input terminal.

[0077] According to this positioning device, the time from when the synchronization signal is output from the first integrated circuit to when it is input to the first integrated circuit and the second integrated circuit can be aligned, thereby more accurately synchronizing the operation timing of the first conversion unit and the operation timing of the second conversion unit.

[0078] In one aspect of the positioning device, the first integrated circuit has a first control terminal for setting it to a master or a slave, and is set to the master by the first control terminal; The second integrated circuit may have a second control terminal for setting it as a master or a slave, and may be set as a slave by the second control terminal.

[0079] According to this positioning device, the first integrated circuit acts as a master and the second integrated circuit acts as a slave, and the first integrated circuit and the second integrated circuit work together to perform positioning.

[0080] In one aspect of the positioning device, The frequency band of the second satellite signal may be lower than the frequency band of the first satellite signal.

[0081] According to this positioning device, the first integrated circuit and the second integrated circuit can receive satellite signals in different frequency bands and capture satellites efficiently.

[0082] In one aspect of the positioning device, the first baseband processing unit generates satellite acquisition information including a frequency offset and a code phase of the first satellite signal based on the first baseband signal; The first integrated circuit may transmit the satellite acquisition information to the second integrated circuit.

[0083] According to this positioning device, the first integrated circuit and the second integrated circuit can share the satellite capture information generated by the first integrated circuit.

[0084] In one aspect of the positioning device, the second integrated circuit receives the satellite acquisition information; The second baseband processing unit may demodulate a navigation message included in the second baseband signal based on the satellite capture information, and perform positioning based on the navigation message.

[0085] According to this positioning device, the second integrated circuit can perform positioning in a short time by using the satellite capture information generated by the first integrated circuit. [Explanation of symbols]

[0086] 1...positioning device, 2...satellite, 10...GNSS receiving IC, 11...antenna, 12...RF processing unit, 13...DDC, 14...downsampling unit, 15...baseband processing unit, 16...timing signal generation unit, 17...CPU, 18...conversion unit, 20...GNSS receiving IC, 21...antenna, 22...RF processing unit, 23...DDC, 24...downsampling unit, 25...baseband processing unit, 26...timing signal generation unit, 27...CPU, 28...conversion unit, 30...TCXO, 40...power supply IC, 50...power supply IC, 60...battery

Claims

1. a first integrated circuit; a second integrated circuit; The first integrated circuit comprises: a first receiver that receives a first satellite signal transmitted from a satellite and converts the first satellite signal into a first intermediate frequency signal; a first converter for converting the first intermediate frequency signal into a first baseband signal; a first baseband processing unit that processes the first baseband signal, The second integrated circuit comprises: a second receiving unit that receives a second satellite signal transmitted from the satellite and converts the second satellite signal into a second intermediate frequency signal; a second conversion unit that converts the second intermediate frequency signal into a second baseband signal; a second baseband processing unit that processes the second baseband signal, a first integrated circuit that transmits a synchronization signal to the second integrated circuit to synchronize a first timing signal that controls the operation timing of the first conversion unit and a second timing signal that controls the operation timing of the second conversion unit of the second integrated circuit.

2. In claim 1, the first integrated circuit has a first output terminal that outputs the synchronization signal to an external device and a first input terminal that receives the synchronization signal from an external device; the second integrated circuit has a second input terminal to which the synchronization signal is input from an external device; A positioning device, wherein the length of a wire connecting the first output terminal and the second input terminal is equal to the length of a wire connecting the first output terminal and the first input terminal.

3. In claim 1, the first integrated circuit has a first control terminal for setting the first integrated circuit to be a master or a slave, and is set to be a master by the first control terminal; The second integrated circuit has a second control terminal for setting the second integrated circuit to a master or a slave, and is set to a slave by the second control terminal.

4. In claim 1, A positioning device, wherein the frequency band of the second satellite signal is lower than the frequency band of the first satellite signal.

5. In claim 1, the first baseband processing unit generates satellite acquisition information including a frequency offset and a code phase of the first satellite signal based on the first baseband signal; The first integrated circuit transmits the satellite capture information to the second integrated circuit.

6. In claim 5, the second integrated circuit receives the satellite acquisition information; The second baseband processing unit demodulates a navigation message included in the second baseband signal based on the satellite capture information, and performs positioning based on the navigation message.

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