Satellite navigation system signal acquisition device and method

Abstract

The present invention discloses a satellite navigation system signal capture device, comprising an intermediate frequency signal preprocessing module and a coherent accumulation module, wherein the intermediate frequency signal preprocessing module preprocesses the received intermediate frequency data signal to obtain zero intermediate frequency preprocessed capture data; the coherent accumulation module comprises a plurality of coherent accumulation channels, each of which comprises a first coherent accumulation unit, a complex square unit, and a selector unit, wherein the first coherent accumulation unit performs coherent accumulation calculation on the zero intermediate frequency preprocessed capture data; the complex square unit performs complex square calculation on the calculation result of the coherent accumulation unit; when the signal processed by the coherent accumulation channel is the first navigation signal, the selector unit outputs the calculation result of the complex square unit, otherwise, the selector unit outputs the calculation result of the coherent accumulation unit, and the first navigation signal is a navigation signal without a pilot component and whose data transmission rate is greater than a preset transmission rate. The capture performance of the satellite navigation signal is effectively improved, and the number of available observation quantities is increased.

Description

Technical Field

[0001] The present invention relates to the field of satellite communications, and in particular to a satellite navigation system signal capture device and method. Background Art

[0002] The global satellite navigation system can provide high-precision, all-weather, global positioning, navigation and timing services, and has been applied to all aspects of production and life. With the development of science and technology, China's Beidou Satellite Navigation System (BDS) has gradually become an important part of the global satellite navigation system. BDS can not only provide high-precision positioning services, but also has unique functions such as short message communication and precise single-point positioning.

[0003] BDS satellites transmit 8 civil signals on 6 carriers, including B2a, B2b, B2I, B3I, B1I, B1C, S1, and S2C. Receivers supporting multi-frequency signals can provide high-quality positioning, velocity measurement, and timing services, and can achieve precise single-point positioning, RTK technology, anti-interference, precise ionosphere modeling, short message communication, and other functions.

[0004] Although BDS has many signals, the application of some signals is still limited, such as signals with high data transmission rate without pilot components, short coherent integration time, and poor signal acquisition and tracking performance, such as B2b signals, GEO B1I signals, B1C SBAS signals, S1 signals, and S2C signals. For high-performance GNSS receivers, the built-in CPU has enough computing power to process more signal observations. If there are more available observations for positioning and timing, the service quality of the GNSS receiver can be improved, and the reliability and stability of the receiver can be further enhanced. Summary of the invention

[0005] Based on the above situation, the main purpose of the present invention is to add a complex square unit in the capture scheme, eliminate the influence of the transmitted data bits and NH codes, allow coherent accumulation for a longer time, effectively improve the capture performance of satellite navigation signals without pilot components and with a high data transmission rate, and increase the number of available observation quantities of the receiver.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A satellite navigation system signal acquisition device includes an intermediate frequency signal preprocessing module and a coherent accumulation module.

[0008] The intermediate frequency signal preprocessing module is used to preprocess the received intermediate frequency data signal to obtain zero intermediate frequency preprocessed captured data;

[0009] The coherent accumulation module includes a plurality of coherent accumulation channels, each of which includes a first coherent accumulation unit, a complex square unit, and a selector unit.

[0010] The first coherent accumulation unit is used to perform coherent accumulation calculation on the zero intermediate frequency preprocessed captured data;

[0011] The complex squaring unit is used to perform complex squaring calculation on the calculation result of the coherent accumulation unit;

[0012] The selector unit is used to output the calculation result of the complex square unit when the signal processed by the coherent accumulation channel is a first navigation signal, otherwise, output the calculation result of the coherent accumulation unit, and the first navigation signal is a navigation signal without a pilot component and with a data transmission rate greater than a preset transmission rate.

[0013] Preferably, the intermediate frequency signal preprocessing module includes a capture intermediate frequency stripping unit, a capture downsampling unit, a capture data buffer unit and a Doppler frequency NCO unit.

[0014] The captured intermediate frequency stripping unit is used to strip the intermediate frequency remaining in the intermediate frequency data signal to move the sampling data frequency band to zero intermediate frequency;

[0015] The capture downsampling unit is used to downsample the zero intermediate frequency sampled data to an integer multiple of the nominal pseudo code rate;

[0016] The captured data buffer unit is used to buffer the data output by the captured downsampling unit;

[0017] The Doppler frequency NCO unit is used to generate a Doppler frequency NCO, and roughly estimate and strip the Doppler frequency of the data of the capture data buffer unit to obtain zero intermediate frequency preprocessing capture data.

[0018] Preferably, for non-BOC modulated signals, the capture downsampling unit downsamples the zero intermediate frequency sampling data to twice the nominal pseudo code rate; for BOC modulated signals, the capture downsampling unit downsamples the zero intermediate frequency sampling data to four or six times the nominal pseudo code rate.

[0019] Preferably, the intermediate frequency signal preprocessing module further includes a spread spectrum code buffer unit, which is used to generate and buffer the spread spectrum code of the designated satellite signal.

[0020] Preferably, the first coherent accumulation unit is The sub-coherent accumulation result is:

[0021]

[0022] in: is the correlation amplitude, , is the sampling rate; To transmit data, +1 or -1; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0023] Preferably, the complex square unit uses the following formula for calculation:

[0024] ;

[0025] in: is the correlation amplitude, , is the sampling rate; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0026] Preferably, the coherent accumulation channel further includes an FFT unit and a non-coherent accumulation unit.

[0027] The FFT unit is used to perform FFT calculation on the output data of the selector unit;

[0028] The non-coherent accumulation unit is used to perform non-coherent accumulation calculation on the output result of the FFT unit.

[0029] Preferably, when the selector unit outputs the calculation result of the complex square unit, the calculation result of the FFT unit is:

[0030] ;

[0031] Among them: The continuous coherent accumulation is within one transmitted data bit. and They are the noise components output by FFT operation respectively;

[0032] make The spectral line with the largest value is the Doppler estimate:

[0033]

[0034] When the selector unit outputs the calculation result of the coherent accumulation unit, the calculation result of the FFT unit is:

[0035] ;

[0036] Among them: The continuous coherent accumulation is within one transmitted data bit. and are the FFT operation output noise components, The spectral line with the largest value is the Doppler estimate:

[0037] ;

[0038] is the correlation amplitude, , is the Doppler frequency; is the coherent accumulation time; is the phase, N is the number of points calculated by FFT, and k is the kth spectral line calculated by FFT.

[0039] Preferably, the coherent accumulation channel further includes a second coherent accumulation unit, and the second coherent accumulation unit is used to perform coherent accumulation on the calculation result of the complex square unit.

[0040] Preferably, the device further comprises a capture decision module, which is used to take the Doppler and pseudo code phase combination corresponding to one or more calculation results with the largest accumulation result output by the coherent accumulation channel as the capture result.

[0041] The present invention also discloses a satellite navigation signal receiving chip, wherein the chip comprises the satellite navigation system signal capturing device of the present invention to capture satellite navigation signals.

[0042] The invention also discloses a Beidou satellite navigation signal receiver, which adopts the satellite navigation signal receiving chip of the invention.

[0043] The present invention also discloses a satellite navigation system signal acquisition method, comprising the steps of:

[0044] S100, preprocessing the received intermediate frequency data signal to obtain zero intermediate frequency preprocessed captured data;

[0045] S200, performing coherent accumulation calculation on the zero intermediate frequency preprocessed captured data;

[0046] S300, performing complex square calculation on the coherent accumulation calculation result;

[0047] S400, when the signal processed by the coherent addition is a first navigation signal, output the calculation result of the complex square, otherwise, output the calculation result of the coherent addition, the first navigation signal is a navigation signal without a pilot component and with a data transmission rate greater than a preset transmission rate.

[0048] Preferably, the step S100 includes:

[0049] S101, stripping the intermediate frequency remaining in the intermediate frequency data signal to move the sampling data frequency band to zero intermediate frequency;

[0050] S103, downsampling the zero intermediate frequency sampled data to an integer multiple of a nominal pseudo code rate;

[0051] S105, buffering the data output by the capture downsampling unit;

[0052] S107, roughly estimating and stripping the Doppler frequency of the cached data to obtain zero intermediate frequency preprocessed captured data.

[0053] Preferably, the step S103 includes:

[0054] For a non-BOC modulated signal, the capture downsampling unit downsamples the zero intermediate frequency sampled data to twice the nominal pseudo code rate;

[0055] For a BOC modulated signal, the capture downsampling unit downsamples the zero intermediate frequency sampled data to 4 times or 6 times the nominal pseudo code rate.

[0056] Preferably, the calculation result of the coherent accumulation calculation performed on the zero intermediate frequency preprocessed captured data in step S200 is:

[0057] ;

[0058] in: is the correlation amplitude, , is the sampling rate; To transmit data, +1 or -1; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0059] Preferably, in step S300, the following formula is used to perform complex square calculation on the coherent accumulation calculation result:

[0060] ;

[0061] in: is the correlation amplitude, , is the sampling rate; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0062] Preferably, the method further comprises the steps of:

[0063] S500, performing FFT calculation on the output data of step S400;

[0064] S600, performing non-coherent accumulation calculation on the FFT calculation result outputted in step S500.

[0065] Preferably, when the complex square calculation result is output, the calculation result of step S500 is:

[0066] ;

[0067] Among them: The continuous coherent accumulation is within one transmitted data bit. and They are the noise components output by FFT operation respectively;

[0068] make The spectral line with the largest value is the Doppler estimate:

[0069]

[0070] When the step S400 outputs the coherent accumulation calculation result, the calculation result of the step S500 is:

[0071] ;

[0072] Among them: The continuous coherent accumulation is within one transmitted data bit. and are the FFT operation output noise components, The spectral line with the largest value is the Doppler estimate:

[0073] ;

[0074] is the correlation amplitude, , is the Doppler frequency; is the coherent accumulation time; is the phase, N is the number of points calculated by FFT, and k is the kth spectral line calculated by FFT.

[0075] Preferably, the step S300 further comprises performing coherent accumulation on the calculation results of the complex squares.

[0076] Preferably, the method further comprises step S700, taking the Doppler and pseudo code phase combination corresponding to one or more calculation results with the largest accumulation result output by the coherent accumulation as the capture result.

[0077] The technical solution of the present invention adds a complex square unit to the capture scheme, eliminates the influence of the transmission data bit and the NH code, can perform coherent accumulation for a longer time, can effectively improve the capture performance of Beidou satellite navigation signals with no pilot component and high data transmission rate, and increase the number of available observation quantities of the receiver. In particular, for signals with high data transmission rates such as B2b signals and GEO B1I signals, the capture sensitivity can be effectively improved. For signals with NH code modulation such as B1I and B3I, the complex square operation can effectively improve the capture sensitivity. For receivers supporting Beidou short messages, the complex square operation can be used to effectively improve the capture sensitivity of S1 / S2C signals.

[0078] Other beneficial effects of the present invention will be explained in the specific implementation manner through the introduction of specific technical features and technical solutions. Through the introduction of these technical features and technical solutions, those skilled in the art should be able to understand the beneficial technical effects brought about by the technical features and technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The preferred embodiments of the satellite navigation system signal acquisition device and method according to the present invention will be described below with reference to the accompanying drawings.

[0080] Figure 1 A schematic diagram of a satellite navigation system signal acquisition device according to a preferred embodiment of the present invention;

[0081] Figure 2 A schematic diagram of an intermediate frequency signal preprocessing module according to a preferred embodiment of the present invention;

[0082] Figure 3 A schematic diagram of an intermediate frequency signal preprocessing module according to another preferred embodiment of the present invention;

[0083] Figure 4 A schematic diagram of a satellite navigation system signal acquisition device according to another preferred embodiment of the present invention;

[0084] Figure 5 A schematic diagram of a satellite navigation system signal acquisition device according to another preferred embodiment of the present invention;

[0085] Figure 6 A circuit block diagram of a capture module designed according to the technical solution of the present invention;

[0086] Figure 7 The present invention is a flowchart of a satellite navigation system signal acquisition method according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0087] Figure 1 A satellite navigation system signal capture device according to a preferred embodiment of the present invention comprises an intermediate frequency signal preprocessing module 100 and a coherent accumulation module 200, wherein the intermediate frequency signal preprocessing module 100 is used to preprocess the received intermediate frequency data signal to obtain zero intermediate frequency preprocessed capture data; the coherent accumulation module 200 comprises a plurality of coherent accumulation channels, each of which comprises a first coherent accumulation unit 201, a complex square unit 202, and a selector unit 203, wherein the first coherent accumulation unit 201 is used to perform coherent accumulation calculation on the zero intermediate frequency preprocessed capture data; the complex square unit 202 is used to perform complex square calculation on the calculation results of the coherent accumulation units; the selector unit 203 is used to output the calculation result of the complex square unit 202 when the signal processed by the coherent accumulation channel is a first navigation signal, otherwise, output the calculation result of the coherent accumulation unit 201, wherein the first navigation signal is a navigation signal having no pilot component and a data transmission rate greater than a preset transmission rate. For example, the preset transmission rate may be selected as 500 Hz.

[0088] The technical solution of the present invention adds a complex square unit to the capture scheme, eliminates the influence of the transmission data bit and the NH code, can perform coherent accumulation for a longer time, can effectively improve the capture performance of Beidou satellite navigation signals with no pilot component and high data transmission rate, and increase the number of available observation quantities of the receiver. In particular, for signals with high data transmission rates such as B2b signals and GEO B1I signals, the capture sensitivity can be effectively improved. For signals with NH code modulation such as B1I and B3I, the complex square operation can effectively improve the capture sensitivity. For receivers supporting Beidou short messages, the complex square operation can be used to effectively improve the capture sensitivity of S1 / S2C signals.

[0089] In a specific implementation, the capture module generally includes a large number of parallel coherent accumulation channels, each channel is responsible for the coherent integration operation of a specific pseudo code sequence, and realizes parallel code phase search.

[0090] In a preferred embodiment, Figure 2As shown, the intermediate frequency signal preprocessing module 100 may include a capture intermediate frequency stripping unit 201, a capture downsampling unit 202, a capture data cache unit 203 and a Doppler frequency NCO unit 204, wherein the capture intermediate frequency stripping unit 201 is used to strip the residual intermediate frequency frequency in the intermediate frequency data signal to move the sampling data frequency band to zero intermediate frequency; the capture downsampling unit 202 is used to downsample the sampling data of the zero intermediate frequency to an integer multiple of the nominal pseudo code rate; the capture data cache unit 203 is used to cache the data output by the capture downsampling unit for capture operation; the Doppler frequency NCO unit 204 is used to generate a Doppler frequency NCO, and roughly estimate and strip the Doppler frequency of the data in the capture data cache unit to obtain zero intermediate frequency preprocessed capture data. Among them, zero intermediate frequency refers to the stripping of the nominal carrier frequency. The data cached after intermediate frequency stripping and downsampling is zero intermediate frequency data. The Doppler frequency is caused by the relative operation of the satellite and the receiver and the rate of change of the clock error. It is unknown and needs to be estimated. Therefore, after obtaining the zero intermediate frequency data, the Doppler frequency estimation and stripping must be performed to obtain zero intermediate frequency pre-processed capture data, thereby reducing the estimation range of the subsequent residual Doppler frequency.

[0091] In a preferred embodiment, for non-BOC modulated signals, the capture downsampling unit downsamples the zero intermediate frequency sampling data to twice the nominal pseudo code rate, such as a B1I signal; for BOC modulated signals, the capture downsampling unit downsamples the zero intermediate frequency sampling data to four or six times the nominal pseudo code rate, such as a B1C signal.

[0092] In a specific implementation, the capture sampling rate is generally between 1MHz and 20MHz, and the capture module performs signal detection at a clock frequency of more than 200MHz. Therefore, the capture data cache unit 203 caches data once, and through multiple playbacks, it can quickly realize the capture operation of multiple satellite signals, thereby accelerating the first positioning time of the receiver cold start.

[0093] In a specific implementation, for the same satellite signal, NCOs with different Doppler frequencies may be generated in a certain order for use in Doppler frequency search and detection.

[0094] In a preferred embodiment, Figure 3As shown, the intermediate frequency signal preprocessing module 100 also includes a spread spectrum code cache unit 105, which is used to generate and cache the spread spectrum code of the specified satellite signal. Before the capture operation starts, the spread spectrum code of the specified satellite signal needs to be generated and cached. After the capture operation starts, multiple spread spectrum codes (pseudo code values) can be read at one time to perform parallel fast correlation operations. However, the solution of generating spread spectrum codes (pseudo code) in real time can only realize parallel operations between different coherent accumulation channels, and it is not easy to realize parallel operations within the coherent accumulation channel.

[0095] In a preferred embodiment, the first coherent accumulation unit The sub-coherent accumulation result is:

[0096] ;

[0097] in: is the correlation amplitude, , is the sampling rate; To transmit data, +1 or -1; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0098] In a preferred embodiment, the complex square unit is calculated using the following formula:

[0099] ;

[0100] in: is the correlation amplitude, , is the sampling rate; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0101] In a preferred embodiment, Figure 4 As shown, the coherent accumulation channel also includes an FFT unit 204 and an incoherent accumulation unit 205, wherein the FFT unit 204 is used to perform FFT calculation on the output data of the selector unit; and the incoherent accumulation unit 205 is used to perform incoherent accumulation calculation on the output result of the FFT unit.

[0102] In a preferred embodiment, when the selector unit 203 outputs the calculation result of the complex square unit, the calculation result of the FFT unit 204 is:

[0103] ;

[0104] Among them: The continuous coherent accumulation is within one transmitted data bit. and They are the noise components output by FFT operation respectively;

[0105] make The spectral line with the largest value is the Doppler estimate:

[0106] .

[0107] When the selector unit 203 outputs the calculation result of the coherent accumulation unit, the calculation result of the FFT unit 204 is:

[0108] ;

[0109] Among them: The continuous coherent accumulation is within one transmitted data bit. and are the noise components output by FFT operation respectively. The spectral line with the largest value is the Doppler estimate:

[0110] ;

[0111] is the correlation amplitude, , is the Doppler frequency; is the coherent accumulation time; is the phase, N is the number of points calculated by FFT, and k is the kth spectral line calculated by FFT.

[0112] When the selector unit outputs the calculation result of the coherent accumulation unit, the FFT processing gain of the noise power is approximately , the FFT processing gain of the signal power is about , the signal-to-noise ratio gain is . Limited by the data bit period, for B2b signal, It can only take 1, the obtained gain is small, and the capture sensitivity is low. When the selector unit outputs the calculation result of the complex square unit, the obtained signal-to-noise ratio gain is less than , which improves the capture sensitivity and eliminates the influence of the telegram data. Since the noise is squared, the signal-to-noise ratio gain obtained is less than L.

[0113] In a preferred embodiment, Figure 5 As shown, the coherent accumulation channel further includes a second coherent accumulation unit 206, and the second coherent accumulation unit 206 is used to perform coherent accumulation on the calculation result of the complex square unit, so as to further increase the coherent gain and improve the capture sensitivity.

[0114] In a preferred embodiment, the satellite navigation system signal acquisition device also includes a acquisition decision module, which is used to take the Doppler and pseudo-code phase combination corresponding to one or several calculation results with the largest global accumulation result output by the coherent accumulation channel as the capture result.

[0115] Figure 6 The circuit block diagram of the capture module designed according to the technical solution of the present invention, wherein the intermediate frequency signal preprocessing module includes the second-level capture intermediate frequency stripping, the second-level capture downsampling, the capture data cache, the Doppler frequency NCO and the spread spectrum code cache, the coherent accumulation module includes N code phase coherent accumulation channels, each coherent accumulation channel includes coherent accumulation, complex squaring, selector MUX, FFT and incoherent accumulation, and finally the output result of each coherent accumulation channel is output after the capture decision.

[0116] The present invention further discloses a satellite navigation signal receiving chip, wherein the chip comprises the satellite navigation system signal capturing device according to any one of the present inventions, so as to capture the satellite navigation signal.

[0117] The invention also discloses a Beidou satellite navigation signal receiver, which adopts the satellite navigation signal receiving chip of the invention.

[0118] The present invention also discloses a satellite navigation system signal acquisition method, such as Figure 7 As shown, comprising the steps of:

[0119] S100, preprocessing the received intermediate frequency data signal to obtain zero intermediate frequency preprocessed captured data;

[0120] S200, performing coherent accumulation calculation on the zero intermediate frequency preprocessed captured data;

[0121] S300, performing complex square calculation on the coherent accumulation calculation result;

[0122] S400, when the signal processed by the coherent addition is a first navigation signal, output the calculation result of the complex square, otherwise, output the calculation result of the coherent addition, the first navigation signal is a navigation signal without a pilot component and with a data transmission rate greater than a preset transmission rate.

[0123] In a preferred embodiment, the step S100 includes, S101, stripping the residual intermediate frequency in the intermediate frequency data signal to move the sampled data frequency band to zero intermediate frequency; S103, downsampling the zero intermediate frequency sampled data to an integer multiple of the nominal pseudo code rate; S105, caching the data output by the capture downsampling unit; S107, roughly estimating and stripping the Doppler frequency of the cached data to obtain zero intermediate frequency preprocessed capture data.

[0124] In a preferred embodiment, the step S103 includes, for a non-BOC modulated signal, the capture downsampling unit downsampling the zero intermediate frequency sampling data to 2 times the nominal pseudo code rate; for a BOC modulated signal, the capture downsampling unit downsampling the zero intermediate frequency sampling data to 4 times or 6 times the nominal pseudo code rate.

[0125] In a preferred embodiment, the calculation result of the coherent accumulation calculation of the zero intermediate frequency pre-processed captured data in step S200 is:

[0126] ;

[0127] in: is the correlation amplitude, , is the sampling rate; To transmit data, +1 or -1; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0128] In a preferred embodiment, in step S300, the following formula is used to perform complex square calculation on the coherent accumulation calculation result:

[0129] ;

[0130] in: is the correlation amplitude, , is the sampling rate; To transmit data, +1 or -1; is the Doppler frequency; is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise.

[0131] In a preferred embodiment, the method further comprises the steps of: S500, performing FFT calculation on the output data of step S400; and S600, performing non-coherent accumulation calculation on the FFT calculation result outputted from step S500.

[0132] In a preferred embodiment, when the complex square calculation result is output, the calculation result of step S500 is:

[0133] ;

[0134] Among them: The continuous coherent accumulation is within one transmitted data bit. and They are the noise components output by FFT operation respectively;

[0135] make The spectral line with the largest value is the Doppler estimate:

[0136]

[0137] When the step S400 outputs the coherent accumulation calculation result, the calculation result of the step S500 is:

[0138] ;

[0139] Among them: The continuous coherent accumulation is within one transmitted data bit. and are the FFT operation output noise components, The spectral line with the largest value is the Doppler estimate:

[0140] ;

[0141] is the correlation amplitude, , is the Doppler frequency; is the coherent accumulation time; is the phase, N is the number of points calculated by FFT, and k is the kth spectral line calculated by FFT.

[0142] In a preferred implementation, the step S300 further includes performing coherent accumulation on the calculation results of the complex squares.

[0143] In a preferred embodiment, the method further comprises step S700, taking the Doppler and pseudo code phase combination corresponding to one or more calculation results with the largest accumulation result output by the coherent accumulation as the capture result.

[0144] It should be noted that the use of step numbers (letters or numbers) to refer to certain specific method steps in the present invention is only for the purpose of convenience and brevity of description, and is by no means intended to limit the order of these method steps. Those skilled in the art will understand that the order of the relevant method steps should be determined by the technology itself and should not be inappropriately limited by the existence of step numbers.

[0145] Those skilled in the art will appreciate that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0146] It should be understood that the above-mentioned embodiments are merely illustrative and not restrictive. Without departing from the basic principles of the present invention, various obvious or equivalent modifications or substitutions that can be made by those skilled in the art to the above-mentioned details will all be included in the scope of the claims of the present invention.

Claims

1. A satellite navigation system signal acquisition device, characterized in that: Including intermediate frequency signal preprocessing module and coherent accumulation module, The intermediate frequency signal preprocessing module is used to preprocess the received intermediate frequency data signal to obtain zero intermediate frequency preprocessed captured data; The coherent accumulation module includes a plurality of coherent accumulation channels, each of which includes a first coherent accumulation unit, a complex square unit, and a selector unit. The first coherent accumulation unit is used to perform coherent accumulation calculation on the zero intermediate frequency preprocessed captured data, and the nth coherent accumulation result of the first coherent accumulation unit is: Where: A is the correlation amplitude, T s is the sampling rate; D(n) is the transmission data, +1 or -1; f d is the Doppler frequency; T coh is the coherent accumulation time; is the phase; N CI (n) is the in-phase component noise, N CQ (n) is the orthogonal component noise; The complex square unit is used to perform complex square calculation on the calculation result of the coherent accumulation unit, and the complex square unit uses the following formula for calculation: Where: A is the correlation amplitude, T s is the sampling rate; f d is the Doppler frequency; T coh is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise; The selector unit is used to output the calculation result of the complex square unit when the signal processed by the coherent accumulation channel is a first navigation signal, otherwise, output the calculation result of the coherent accumulation unit, and the first navigation signal is a navigation signal without a pilot component and with a data transmission rate greater than a preset transmission rate.

2. The satellite navigation system signal acquisition device according to claim 1, characterized in that: The intermediate frequency signal preprocessing module includes a capture intermediate frequency stripping unit, a capture downsampling unit, a capture data buffer unit and a Doppler frequency NCO unit. The captured intermediate frequency stripping unit is used to strip the intermediate frequency remaining in the intermediate frequency data signal to move the sampling data frequency band to zero intermediate frequency; The capture downsampling unit is used to downsample the zero intermediate frequency sampled data to an integer multiple of the nominal pseudo code rate; The captured data buffer unit is used to buffer the data output by the captured downsampling unit; The Doppler frequency NCO unit is used to generate a Doppler frequency NCO, and roughly estimate and strip the Doppler frequency of the data of the capture data buffer unit to obtain zero intermediate frequency preprocessing capture data.

3. The satellite navigation system signal acquisition device according to claim 2, characterized in that: For a non-BOC modulated signal, the capture downsampling unit downsamples the zero intermediate frequency sampled data to 2 times the nominal pseudo code rate; For a BOC modulated signal, the capture downsampling unit downsamples the zero intermediate frequency sampled data to 4 times or 6 times the nominal pseudo code rate.

4. The satellite navigation system signal acquisition device according to claim 2, characterized in that: The intermediate frequency signal preprocessing module also includes a spread spectrum code buffer unit, which is used to generate and buffer the spread spectrum code of the designated satellite signal.

5. The satellite navigation system signal acquisition device according to claim 1, characterized in that: The coherent accumulation channel also includes an FFT unit and a non-coherent accumulation unit. The FFT unit is used to perform FFT calculation on the output data of the selector unit; The non-coherent accumulation unit is used to perform non-coherent accumulation calculation on the output result of the FFT unit.

6. The satellite navigation system signal acquisition device according to claim 5, characterized in that: When the selector unit outputs the calculation result of the complex square unit, the calculation result of the FFT unit is: Among them: L consecutive coherent accumulations participating in the FFT operation are included in one transmission data bit, N XI (k) and N XQ (k) are the noise components output by FFT operation; Let X(k)| have the largest value corresponding to the spectral line k max is the Doppler estimate: When the selector unit outputs the calculation result of the coherent accumulation unit, the calculation result of the FFT unit is: Among them: L consecutive coherent accumulations participating in the FFT operation are included in one transmission data bit, N XI (k) and N XQ (k) are the noise components of the FFT operation output, and the corresponding spectral line k is set to have the largest value of |X(k)| max is the Doppler estimate: A is the correlation amplitude, f d is the Doppler frequency; T coh is the coherent accumulation time; is the phase, N is the number of points calculated by FFT, and k is the kth spectral line calculated by FFT.

7. The satellite navigation system signal acquisition device according to claim 1, characterized in that: The coherent accumulation channel further includes a second coherent accumulation unit, The second coherent accumulation unit is used to perform coherent accumulation on the calculation result of the complex squaring unit.

8. The satellite navigation system signal acquisition device according to any one of claims 1 to 7, characterized in that: The device also includes a capture decision module, The capture decision module is used to take the Doppler and pseudo code phase combination corresponding to one or more calculation results with the largest accumulation result output by the coherent accumulation channel as the capture result.

9. A satellite navigation signal receiving chip, characterized in that: The chip includes the satellite navigation system signal acquisition device as described in any one of claims 1-8, so as to capture satellite navigation signals.

10. A Beidou satellite navigation signal receiver, characterized in that: Use the satellite navigation signal receiving chip as claimed in claim 9.

11. A satellite navigation system signal acquisition method, characterized in that: Including steps, S100, preprocessing the received intermediate frequency data signal to obtain zero intermediate frequency preprocessed captured data; S200, performing coherent accumulation calculation on the zero intermediate frequency preprocessed captured data, and the calculation result of performing coherent accumulation calculation on the zero intermediate frequency preprocessed captured data is: Where: A is the correlation amplitude, T s is the sampling rate; D(n) is the transmission data, +1 or -1; f d is the Doppler frequency; T coh is the coherent accumulation time; is the phase; N CI (n) is the in-phase component noise, N CQ (n) is the orthogonal component noise; S300, performing complex square calculation on the coherent accumulation calculation result using the following formula: Where: A is the correlation amplitude, T s is the sampling rate; f d is the Doppler frequency; T coh is the coherent accumulation time; is the phase; is the in-phase component noise, is the orthogonal component noise; S400, when the signal processed by the coherent addition is a first navigation signal, output the calculation result of the complex square, otherwise, output the calculation result of the coherent addition, the first navigation signal is a navigation signal without a pilot component and with a data transmission rate greater than a preset transmission rate.

12. The satellite navigation system signal acquisition method according to claim 11, characterized in that: The step S100 includes: S101, stripping the intermediate frequency remaining in the intermediate frequency data signal to move the sampling data frequency band to zero intermediate frequency; S103, downsampling the zero intermediate frequency sampled data to an integer multiple of a nominal pseudo code rate; S105, buffering the data output by the capture downsampling unit; S107, roughly estimating and stripping the Doppler frequency of the cached data to obtain zero intermediate frequency preprocessed captured data.

13. The satellite navigation system signal acquisition method according to claim 12, characterized in that: The step S103 includes: For a non-BOC modulated signal, the capture downsampling unit downsamples the zero intermediate frequency sampled data to 2 times the nominal pseudo code rate; For a BOC modulated signal, the capture downsampling unit downsamples the zero intermediate frequency sampled data to 4 times or 6 times the nominal pseudo code rate.

14. The satellite navigation system signal acquisition method according to claim 11, characterized in that: The method further comprises the steps of, S500, performing FFT calculation on the output data of step S400; S600, performing non-coherent accumulation calculation on the FFT calculation result outputted in step S500.

15. The satellite navigation system signal acquisition method according to claim 14, characterized in that: When the complex square calculation result is output, the calculation result of step S500 is: Among them: L consecutive coherent accumulations participating in the FFT operation are included in one transmission data bit, N XI (k) and N XQ (k) are the noise components output by FFT operation; Let the spectral line kmax corresponding to the maximum value of X(k)| be the Doppler estimation value: When the step S400 outputs the coherent accumulation calculation result, the calculation result of the step S500 is: Among them: L consecutive coherent accumulations participating in the FFT operation are included in one transmission data bit, N XI (k) and N XQ (k) are the noise components of the FFT operation output, and the corresponding spectral line k is set to have the largest value of |X(k)| max is the Doppler estimate: A is the correlation amplitude, f d is the Doppler frequency; T coh is the coherent accumulation time; is the phase, N is the number of points calculated by FFT, and k is the kth spectral line calculated by FFT.

16. The satellite navigation system signal acquisition method according to claim 11, characterized in that: The step S300 further includes performing coherent accumulation on the calculation results of the complex squares.

17. The satellite navigation system signal acquisition method according to any one of claims 11 to 16, characterized in that: The method further comprises step S700 of taking the Doppler and pseudo code phase combination corresponding to one or more calculation results with the largest accumulation result output by the coherent accumulation as the capture result.

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