Satellite signal capturing method and device, equipment, storage medium and program product

Abstract

The invention provides a satellite signal capturing method and device, equipment, a storage medium and a program product, which can be applied to the technical field of satellite communication. The method comprises the following steps: carrying out carrier stripping on a received initial satellite signal to obtain a first satellite signal; performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal; performing time delay compensation on the second satellite signal to obtain a third satellite signal; performing partial matched filtering and peak value generation processing based on fast Fourier transform on the third satellite signal to obtain a frequency spectrum peak value; performing peak detection based on the spectrum peak to obtain a capture result; the capture result represents capture success or capture failure. The capture accuracy is improved.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to a satellite signal capture method, device, equipment, storage medium and program product. Background Art

[0002] High-dynamic satellite signal capture refers to the process of user equipment (UE) capturing satellite signals in a high-speed moving or dynamically changing environment. There is a high-speed relative motion between the satellite and the UE, which causes the satellite signal received by the UE to be affected by the Doppler frequency deviation. In addition, changes in the signal propagation path will cause changes in the delay, which in turn affects the capture accuracy. Therefore, a method that can accurately capture satellite signals is urgently needed. Summary of the invention

[0003] The present application provides a satellite signal capture method, device, equipment, storage medium and program product to improve capture accuracy.

[0004] In a first aspect, the present application provides a satellite signal acquisition method, comprising:

[0005] Carrier stripping is performed on the received initial satellite signal to obtain a first satellite signal;

[0006] Performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal;

[0007] Performing time delay compensation on the second satellite signal to obtain a third satellite signal;

[0008] Performing partial matched filtering and fast Fourier transform-based peak generation processing on the third satellite signal to obtain a spectrum peak;

[0009] Peak detection is performed based on the spectrum peak to obtain a capture result; the capture result indicates capture success or capture failure.

[0010] In some embodiments, the Doppler effect compensation includes frequency offset compensation and frequency offset change rate compensation, and the code Doppler effect compensation includes code rate offset compensation and code rate offset change rate compensation; performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal includes:

[0011] Performing frequency offset compensation on the first satellite signal to obtain a fourth satellite signal;

[0012] Performing code rate offset compensation on the fourth satellite signal to obtain a fifth satellite signal;

[0013] performing frequency deviation change rate compensation on the fifth satellite signal to obtain a sixth satellite signal;

[0014] The code rate offset change rate compensation is performed on the sixth satellite signal to obtain a second satellite signal.

[0015] In some embodiments, performing frequency offset compensation on the first satellite signal to obtain a fourth satellite signal includes:

[0016] Multiplying the first satellite signal by a first-order phase adjustment term to obtain a fourth satellite signal; the first-order phase adjustment term is exp(-j2π·f1·t);

[0017] Wherein, exp represents exponential operation, j is an imaginary unit, f1 is the estimated value of Doppler frequency offset, and t is time.

[0018] In some embodiments, the Doppler frequency offset estimation value is determined based on at least one of the following methods: frequency offset scanning estimation, ephemeris calculation, or use of historical capture results.

[0019] In some embodiments, the frequency offset scanning estimation includes:

[0020] The Doppler frequency offset estimation formula is used to determine the Doppler frequency offset estimation value; the frequency offset scanning estimation formula is:

[0021] f1=(-N FL1 +2n1-1)·fls1 / 2,n1=1,2,...,N FL1

[0022] Among them, N FL1 is the total number of frequency offset scans, n1 is the current number of frequency offset scans, and fls1 is the frequency offset scan step.

[0023] In some embodiments, performing code rate offset compensation on the fourth satellite signal to obtain a fifth satellite signal includes:

[0024] The fourth satellite signal is sampled according to a zero-order time-varying sampling rate to obtain a fifth satellite signal; the zero-order time-varying sampling rate is:

[0025] fs0=fsb / fc0·(fc0+fc1)

[0026] Wherein, fs0 is the zero-order time-varying sampling rate, fsb is the baseband sampling rate, fc0 is the nominal value of the pseudo-random code rate, and fc1 is the estimated value of the Doppler code rate offset.

[0027] In some embodiments, it also includes:

[0028] The Doppler code rate offset estimation formula is used to determine the Doppler code rate offset estimation value; the code rate offset estimation formula is:

[0029] fc1=f1·fc0 / fr

[0030] Wherein, fc1 is the estimated value of Doppler code rate offset, f1 is the estimated value of Doppler frequency deviation, fc0 is the nominal value of pseudo-random code rate, and fr is the nominal value of RF carrier frequency.

[0031] In some embodiments, performing frequency deviation change rate compensation on the fifth satellite signal to obtain a sixth satellite signal includes:

[0032] The fifth satellite signal is multiplied by a second-order phase adjustment term to obtain a sixth satellite signal; the second-order phase adjustment term is exp(-j2π·f2·t 2 / 2);

[0033] Wherein, exp represents exponential operation, j is an imaginary unit, f2 is the estimated value of the Doppler frequency deviation change rate, and t is time.

[0034] In some embodiments, the Doppler frequency offset change rate estimate is determined based on at least one of the following methods: frequency offset change rate scanning estimate, ephemeris calculation, or use of historical capture results.

[0035] In some embodiments, the frequency deviation change rate scanning estimation includes:

[0036] The Doppler frequency deviation change rate estimation value is determined by using a frequency deviation change rate scanning estimation formula; the frequency deviation change rate scanning estimation formula is:

[0037] f2=(-N FL2 +2n2-1)·fls2 / 2,n2=1,2,...,N FL2

[0038] Among them, N FL2 is the total number of frequency deviation change rate scans, n2 is the current number of frequency deviation change rate scans, and fls2 is the frequency deviation change rate scan step.

[0039] In some embodiments, performing code rate offset change rate compensation on the sixth satellite signal to obtain a second satellite signal includes:

[0040] The sixth satellite signal is sampled according to a first-order time-varying sampling rate to obtain a second satellite signal; the first-order time-varying sampling rate is:

[0041] fs1(t)=fs0 / fc0·(fc0+fc2·t)

[0042] Wherein, fs1(t) is the first-order time-varying sampling rate, fs0 is the zero-order time-varying sampling rate, fc0 is the nominal value of the pseudo-random code rate, t is the time, and fc2 is the estimated value of the Doppler code rate offset change rate.

[0043] In some embodiments, it also includes:

[0044] The Doppler code rate offset change rate estimation formula is used to determine the Doppler code rate offset change rate estimation value; the code rate offset change rate estimation formula is:

[0045] fc2=f2·fc0 / fr

[0046] Wherein, fc2 is the estimated value of the Doppler code rate offset change rate, f2 is the estimated value of the Doppler frequency deviation change rate, fc0 is the nominal value of the pseudo-random code rate, and fr is the nominal value of the RF carrier frequency.

[0047] In some embodiments, the Doppler effect compensation includes frequency offset compensation and frequency offset change rate compensation, and the code Doppler effect compensation includes code rate offset compensation and code rate offset change rate compensation; performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal includes:

[0048] Performing frequency offset compensation on the first satellite signal to obtain a fourth satellite signal;

[0049] performing frequency deviation change rate compensation on the fourth satellite signal to obtain a seventh satellite signal;

[0050] performing code rate offset compensation on the seventh satellite signal to obtain an eighth satellite signal;

[0051] The eighth satellite signal is compensated for a code rate offset change rate to obtain a second satellite signal.

[0052] In some embodiments, performing delay compensation on the second satellite signal to obtain a third satellite signal includes:

[0053] A third satellite signal having the same length as the pseudo-random code signal is intercepted from a position indicated by the estimated delay value in the second satellite signal; the estimated delay value is determined based on a delay scan estimation formula; the delay scan estimation formula is:

[0054] CNT=n3 / fsb,n3=1,2,...,Ns-N cs +1

[0055] Wherein, CNT is the estimated delay value, n3 is the current delay scan times, fsb is the baseband sampling rate, Ns is the total number of sampling points of the second satellite signal, and N csis the total number of sampling points of the pseudo-random code signal at the baseband sampling rate.

[0056] In some embodiments, performing peak detection based on the spectrum peak to obtain a capture result includes:

[0057] Determining a peak threshold based on a signal-to-noise ratio of the initial satellite signal;

[0058] If the spectrum peak value does not exceed the peak threshold, determining a capture result based on at least one of the current delay scan number, the current frequency offset change rate scan number, and the current frequency offset scan number;

[0059] If the spectrum peak value exceeds the peak value threshold, the capture result is determined to be a successful capture.

[0060] In some embodiments, determining the peak threshold based on the signal-to-noise ratio of the initial satellite signal includes:

[0061] Based on the signal-to-noise ratio of the initial satellite signal, a threshold determination formula is used to determine the peak threshold; the threshold determination formula is:

[0062] th=T0·K·10 NF / 10 fsc (Gn+snr Gs) / 2

[0063] Where th is the peak threshold, T0 is the noise temperature, K is the Boltzmann constant, NF is the noise factor, fsc is the digital intermediate frequency sampling rate, Gn is the noise gain, and Gs is the signal gain.

[0064] In some embodiments, the process of determining the noise gain includes:

[0065] Using each of the multiple noise signals as an excitation source of a preset capture algorithm, determining a power ratio of each of the noise signals; the power ratio is a ratio between a maximum power of an output response signal corresponding to the noise signal and a power of the noise signal;

[0066] An average value of power ratios of a plurality of the noise signals is determined as the noise gain.

[0067] In some embodiments, the process of determining the signal gain includes:

[0068] Using each of the plurality of training signals as an excitation source of a preset capture algorithm, determining a power ratio of each of the training signals; the power ratio is a ratio between a maximum power of an output response signal corresponding to the training signal and a power of the training signal; the training signal is a signal that conforms to a satellite signal system, contains a pseudo-random code consistent with a local signal, and has a signal-to-noise ratio greater than a preset signal-to-noise ratio threshold;

[0069] An average value of power ratios of a plurality of the training signals is determined as the signal gain.

[0070] In some embodiments, determining the capture result based on at least one of the current delay scan number, the current frequency offset change rate scan number, and the current frequency offset scan number includes:

[0071] Determine whether the current delay scan number has reached an upper limit;

[0072] If the current delay scan number does not reach the upper limit, a first loop operation is performed based on the remaining delay estimate values ​​in the delay set to be scanned, until it is determined that the capture result is successful capture or the current delay scan number reaches the upper limit; the first loop operation includes performing delay compensation on the second satellite signal based on the delay estimate value corresponding to the next delay scan number in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and fast Fourier transform-based peak generation processing on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result;

[0073] If the current delay scan times have reached the upper limit, the capture result is determined to be a capture failure, or the capture result is determined based on at least one of the current frequency offset change rate scan times and the current frequency offset scan times.

[0074] In some embodiments, the determining the capture result based on at least one of the current frequency offset change rate scanning number and the current frequency offset scanning number includes:

[0075] Determine whether the current frequency deviation change rate scanning times has reached an upper limit value;

[0076] If the current frequency offset change rate scanning times does not reach the upper limit, a second loop operation is performed based on the remaining Doppler frequency offset change rate estimated values ​​in the frequency offset change rate set to be scanned, until it is determined that the capture result is successful capture or the current frequency offset change rate scanning times reaches the upper limit; the second loop operation includes performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal based on the Doppler frequency offset change rate estimated value corresponding to the next frequency offset change rate scanning times in the frequency offset change rate set to be scanned, so as to obtain a new second satellite signal, and performing a third loop operation based on the delay estimated value in the delay set to be scanned, until it is determined that the capture result is successful capture or the current delay scanning times has reached the upper limit; the third loop operation includes performing delay compensation on the new second satellite signal based on the delay estimated value in the delay set to be scanned, so as to obtain a new third satellite signal, and performing partial matched filtering and peak generation processing based on fast Fourier transform on the new third satellite signal, so as to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result;

[0077] If the current frequency offset change rate scanning times has reached the upper limit, the capture result is determined to be a capture failure, or the capture result is determined based on the current frequency offset scanning times.

[0078] In some embodiments, determining the capture result based on the current frequency offset scan number includes:

[0079] Determine whether the current frequency deviation scan times has reached an upper limit;

[0080] If the current number of frequency offset scans has not reached the upper limit, a fourth loop operation is performed based on the remaining Doppler frequency offset estimates in the frequency offset set to be scanned until the capture result is determined to be successful or the current number of frequency offset scans reaches the upper limit; the fourth loop operation includes performing Doppler effect compensation on the first satellite signal based on the Doppler frequency offset estimate corresponding to the next frequency offset scan number in the frequency offset set to be scanned, and performing a fifth loop operation based on the Doppler frequency offset change rate estimate in the frequency offset change rate set to be scanned until the capture result is determined to be successful or the current number of frequency offset change rate scans reaches the upper limit; the fifth loop operation includes performing Doppler effect compensation on the first satellite signal based on the Doppler frequency offset estimate corresponding to the next frequency offset scan number in the frequency offset set to be scanned. The method further comprises: performing code Doppler effect compensation on the Doppler frequency offset change rate estimate in the change rate set to obtain a new second satellite signal, and performing a sixth loop operation based on the delay estimate in the delay set to be scanned, until it is determined that the capture result is successful capture or the current delay scan number has reached an upper limit; the sixth loop operation includes performing delay compensation on the new second satellite signal based on the delay estimate in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and fast Fourier transform-based peak generation processing on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result;

[0081] If the current frequency offset scanning times has reached the upper limit, it is determined that the capture result is a capture failure.

[0082] In some embodiments, the capture result further includes a reference compensation value; the reference compensation value is used for historical capture results, and the reference compensation value includes a reference Doppler frequency deviation, a reference Doppler frequency deviation change rate, a reference Doppler code rate offset, a reference Doppler code rate offset change rate and a reference delay;

[0083] After determining that the capture result is a capture success, the method further includes:

[0084] Determine the current delay estimate as the reference delay;

[0085] Determine the current Doppler frequency deviation change rate estimate as the reference Doppler frequency deviation change rate;

[0086] Based on the reference Doppler frequency deviation change rate, a code rate offset change rate estimation formula is used to determine a reference Doppler code rate offset change rate;

[0087] Determine the current Doppler frequency offset estimate as the first frequency offset component, and determine the second frequency offset component using a frequency offset component determination formula based on the frequency spectrum position corresponding to the frequency spectrum peak;

[0088] Determine the sum of the first frequency offset component and the second frequency offset component as a reference Doppler frequency offset;

[0089] Based on the reference Doppler frequency offset, a code rate offset estimation formula is used to determine a reference Doppler code rate offset.

[0090] In a second aspect, the present application provides a satellite signal acquisition device, comprising:

[0091] A carrier stripping module, used for stripping the carrier of the received initial satellite signal to obtain a first satellite signal;

[0092] A Doppler compensation module, configured to perform Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal;

[0093] A delay compensation module, configured to perform delay compensation on the second satellite signal to obtain a third satellite signal;

[0094] A correlation despreading module, used for performing partial matched filtering and peak generation processing based on fast Fourier transform on the third satellite signal to obtain a spectrum peak;

[0095] The peak detection module is used to perform peak detection based on the spectrum peak to obtain a capture result; the capture result indicates capture success or capture failure.

[0096] In a third aspect, the present application provides an electronic device, comprising: a processor and a memory communicatively connected to the processor;

[0097] The memory stores computer-executable instructions;

[0098] The processor executes the computer-executable instructions stored in the memory to implement the satellite signal acquisition method as described in any one of the first aspects.

[0099] In a fourth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the satellite signal acquisition method described in any one of the first aspects.

[0100] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the satellite signal acquisition method described in any one of the first aspects.

[0101] The satellite signal capture method, apparatus, device, storage medium and program product provided in the present application sequentially perform carrier stripping, distortion compensation, correlation despreading and peak detection on the received initial satellite signal. In the distortion compensation link, Doppler effect compensation, code Doppler effect compensation and delay compensation are performed on the satellite signal, thereby providing more accurate input data for correlation despreading and peak detection, thereby improving the capture accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0103] Figure 1 It is a schematic diagram of an application scenario provided by this application;

[0104] Figure 2 It is a flowchart of a satellite signal acquisition method provided by the present application;

[0105] Figure 3 It is a flowchart of another satellite signal acquisition method provided by the present application;

[0106] Figure 4 It is a flowchart of another satellite signal acquisition method provided by the present application;

[0107] Figure 5 It is a flowchart of another satellite signal acquisition method provided by the present application;

[0108] Figure 6 It is a flowchart of a reliable acquisition algorithm for high-dynamic satellite signals provided by the present application;

[0109] Figure 7 It is a flowchart of another reliable acquisition algorithm for high-dynamic satellite signals provided by the present application;

[0110] Figure 8 It is a flowchart of another reliable acquisition algorithm for high-dynamic satellite signals provided by the present application;

[0111] Fig. 9 It is a flowchart of another reliable acquisition algorithm for high-dynamic satellite signals provided by the present application;

[0112] Fig.10 It is a flowchart of another reliable acquisition algorithm for high-dynamic satellite signals provided by the present application;

[0113] Fig.11 It is a structural schematic diagram of a satellite signal acquisition device provided by the present application;

[0114] Fig.12It is a structural schematic diagram of an electronic device provided by this application.

[0115] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0116] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0117] Figure 1 is a schematic diagram of an application scenario provided by this application. Figure 1 As shown, the application scenario includes: an orbiting satellite and a receiver. The orbiting satellite is used to broadcast satellite signals. The receiver is used to receive satellite signals broadcast by the orbiting satellite and complete the capture of satellite signals by executing the satellite signal capture method provided by the present invention.

[0118] Exemplarily, the orbital satellite is a low-orbit satellite. Exemplarily, the receiver is a user device, for example, the user device may be a satellite communication terminal, a satellite navigation receiver, a remote sensing satellite ground receiving station, or other device capable of communicating with a satellite.

[0119] The satellite signal acquisition method provided in the present application is implemented by a satellite signal acquisition device, which is integrated into an electronic device. Optionally, the electronic device is the user equipment mentioned above.

[0120] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0121] Figure 2 FIG. 1 is a flow chart of a satellite signal acquisition method provided by the present application. Figure 2 As shown, this embodiment takes the electronic device as a receiver as an example for explanation, and the satellite signal acquisition method provided by this embodiment includes the following steps:

[0122] Step S101: Carrier stripping is performed on a received initial satellite signal to obtain a first satellite signal.

[0123] In one scenario, the receiver communicates with an orbiting satellite, and the receiver is capable of receiving satellite signals transmitted by the orbiting satellite. The initial satellite signal refers to the original unprocessed satellite signal received by the receiver.

[0124] Optionally, step S101 is implemented as follows: converting the initial satellite signal through the RF front end to obtain a digital intermediate frequency signal; generating a local cosine carrier and a local sine carrier respectively according to the nominal intermediate frequency; mixing and low-pass filtering the I-channel signal of the digital intermediate frequency signal according to the local cosine carrier to obtain an I-channel output signal, and mixing and low-pass filtering the Q-channel signal of the data intermediate frequency signal according to the local sine carrier to obtain a Q-channel output signal; complexifying the I-channel output signal as the real part and the Q-channel output signal as the imaginary part to construct a first satellite signal. The I-channel signal refers to the in-phase component, and the Q-channel signal refers to the quadrature component. For example, the first satellite signal is a complex baseband signal s(t).

[0125] Step S102: Perform Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal.

[0126] Wherein, the Doppler effect compensation includes at least one of frequency offset compensation and frequency offset change rate compensation, and the code Doppler effect compensation includes at least one of code rate offset compensation and code rate offset change rate compensation. Optionally, the Doppler effect compensation is implemented by high-order time-varying phase adjustment processing, and the code Doppler effect compensation is implemented by high-order time-varying sampling rate adjustment processing.

[0127] Optionally, the high-order time-varying phase adjustment process is implemented as follows: multiplying the satellite signal by the phase adjustment term exp(-jφ(t)). Wherein, exp represents an exponential operation, which is used to calculate the xth power of e, that is, exp(x) is equivalent to e x ; j is the imaginary unit, which is a basic element in complex numbers and satisfies j 2 =-1; φ(t) is a phase function, and φ(t) has the following structure:

[0128]

[0129] Wherein, t is time, indicating a certain moment in the process of signal propagation or reception; d is the Doppler frequency deviation change order, d = 0, 1, 2, ..., D, D is the upper limit of the Doppler frequency deviation change order determined by the dynamics of the satellite application scenario; f d is the phase adjustment parameter.

[0130] When d = 1, φ(t) = 2πf1·t, and the first-order phase adjustment term is exp(-j2π·f1·t); when d = 2, φ(t) = 2π·f2·t 2 / 2, the second-order phase adjustment term is exp(-j2π·f2·t 2 / 2).

[0131] Optionally, regarding the phase adjustment parameter f d When d=1, f1 is the estimated value of Doppler frequency deviation; when d=2, f2 is the estimated value of Doppler frequency deviation change rate.

[0132] Optionally, the high-order time-varying sampling rate adjustment process is implemented as follows: down-sampling the phase-adjusted satellite signal at time t according to the sampling rate fs(t), wherein the sampling rate function fs(t) has the following structure:

[0133]

[0134] Wherein, fsb is the baseband sampling rate set by the receiver by default; fc0 is the nominal value of the pseudo-random code rate; t is the time; d′ is the Doppler code rate offset change order, d′=0,1,2…,D′, D′ is the upper limit of the Doppler code rate offset change order determined by the dynamics of the satellite application scenario; fc d′+1 Adjust the parameters for the sampling rate.

[0135] When d′=0, the zero-order time-varying sampling rate is fs0, and fs0=fsb / fc0·(fc0+fc1); when d′=1, the first-order time-varying sampling rate is fs1(t), and fs1(t)=fs0 / fc0·(fc0+fc2·t).

[0136] Optionally, regarding the sampling rate adjustment parameter fc d′+1 When d′=0, fc1 is equal to the estimated value of Doppler code rate offset; when d′=1, fc2 is equal to the estimated value of Doppler code rate offset change rate.

[0137] Optionally, the phase adjustment parameter f is determined by parameter scanning. d and sampling rate adjustment parameter fc d′+1 When , the following relationship can also be used to reduce the parameter scanning space:

[0138] fc d′+1 =f d ·fc0 / fr

[0139] Wherein, d′+1=d, fc0 is the nominal value of the pseudo-random code rate, and fr is the nominal value of the radio frequency carrier frequency.

[0140] Step S103: Perform time delay compensation on the second satellite signal to obtain a third satellite signal.

[0141] Among them, delay compensation is used to compensate for the offset caused by time delay in satellite signals.

[0142] Step S104: perform partial matched filtering and fast Fourier transform-based peak generation processing on the third satellite signal to obtain a spectrum peak.

[0143] In this embodiment, step S104 is equivalent to performing correlation despreading on the third satellite signal.

[0144] Optionally, the Piecewise Matched Filter (PMF) is implemented as follows: a locally generated pseudo-random code signal is conjugate-multiplied with the third satellite signal; the conjugate-multiplied output signal is evenly divided into N F Segment; sum each segment of the signal to obtain a sampling point length of N F The output signal.

[0145] Among them, N F The number of signal segments used for conjugate multiplication is determined by the frequency offset scanning step length fls1, that is, Among them, N cs is the total number of sampling points of the local pseudo-random code signal at the baseband sampling rate, Indicates rounding x upwards, where fsb is the default baseband sampling rate of the receiver.

[0146] Optionally, the peak generation process is implemented as follows: the sampling point length of the above PMF process output is N F The output signal is N T The Fast Fourier Transform (FFT) of the point is obtained, and the sampling point length is N T The spectrum (also called frequency domain signal) is obtained, and then the maximum value in the obtained spectrum is found, which is also the spectrum peak.

[0147] Among them, N T is the number of FFT points, and Here, lb() represents a logarithmic function with base 2.

[0148] Step S105, performing peak detection based on the spectrum peak to obtain a capture result; the capture result indicates capture success or capture failure.

[0149] Optionally, step S105 is implemented as follows: if the spectrum peak value exceeds the peak value threshold, the capture result is determined to be a capture success; otherwise, if the spectrum peak value does not exceed the peak value threshold, the capture result is determined to be a capture failure. The peak value threshold can be set according to actual needs, and this application does not limit this.

[0150] In practical applications, successfully captured satellite signals are used for subsequent signal tracking and demodulation.

[0151] This embodiment performs carrier stripping, distortion compensation, correlation despreading, and peak detection on the received initial satellite signal in sequence. In the distortion compensation link, Doppler effect compensation, code Doppler effect compensation, and delay compensation are performed on the satellite signal, thereby providing more accurate input data for correlation despreading and peak detection, thereby improving capture accuracy.

[0152] In some embodiments, Figure 3 As shown, step S102 is specifically implemented as the following steps S201-S204:

[0153] Step S201: Perform frequency offset compensation on a first satellite signal to obtain a fourth satellite signal.

[0154] In some embodiments, step S201 is implemented as: multiplying the first satellite signal by a first-order phase adjustment term to obtain a fourth satellite signal.

[0155] The first-order phase adjustment term is exp(-j2π·f1·t); exp represents exponential operation, j is an imaginary unit, f1 is a Doppler frequency offset estimate, and t is time. In this embodiment, the frequency offset caused by the Doppler effect can be effectively compensated by multiplying the first satellite signal by the first-order phase adjustment term. This compensation helps to adjust the signal frequency back to its original frequency, thereby improving the signal quality.

[0156] In some embodiments, the Doppler frequency offset estimation value is determined based on at least one of the following methods: frequency offset scanning estimation, ephemeris calculation, or use of historical acquisition results.

[0157] Among them, ephemeris calculation refers to determining the Doppler frequency deviation estimate based on known ephemeris data and the current position and speed of the receiver. Ephemeris data includes the orbital parameters of the satellite and other related information, such as the position and speed of the satellite, which are usually broadcast regularly by the satellite and received and decoded by the receiver. The specific implementation process of ephemeris calculation refers to the relevant technical means, and this application does not limit this.

[0158] The historical capture result is used to directly use the Doppler frequency deviation estimate determined in the most recent historical capture process of the same satellite and the same frequency point signal.

[0159] In some embodiments, the method of determining the Doppler frequency offset estimation value by frequency offset scanning estimation is specifically implemented as follows: determining the Doppler frequency offset estimation value by using a frequency offset scanning estimation formula. The frequency offset scanning estimation formula is:

[0160] f1=(-N FL1 +2n1-1)·fls1 / 2,n1=1,2,...,N FL1

[0161] Among them, N FL1 is the total number of frequency offset scans, n1 is the current number of frequency offset scans, and fls1 is the frequency offset scan step.

[0162] This embodiment can systematically cover the possible frequency deviation range by defining the total number of frequency deviation scans and the frequency deviation scan step size; the frequency deviation scan estimation formula provides a simple calculation method, which generates a series of Doppler frequency deviation estimation values ​​by iterating the value of n1. This method is relatively simple and easy to implement, and can be efficiently executed in hardware or software; by reasonably setting the frequency deviation scan step size and the total number of frequency deviation scans, the method can converge to a reasonable Doppler frequency deviation estimation value in a shorter time, thereby speeding up the signal capture and processing speed.

[0163] Step S202: Perform code rate offset compensation on the fourth satellite signal to obtain a fifth satellite signal.

[0164] In some embodiments, step S202 is implemented as follows: sampling the fourth satellite signal according to a zero-order time-varying sampling rate to obtain a fifth satellite signal; wherein the zero-order time-varying sampling rate is:

[0165] fs0=fsb / fc0·(fc0+fc1)

[0166] Wherein, fs0 is the zero-order time-varying sampling rate, fsb is the baseband sampling rate, fc0 is the nominal value of the pseudo-random code rate, t is the time, and fc1 is the estimated value of the Doppler code rate offset.

[0167] This embodiment uses a zero-order time-varying sampling rate to downsample the fourth satellite signal to compensate for the code rate offset caused by the Doppler effect, and the code rate offset compensation ensures that the pseudo-random code of the receiver remains synchronized with the satellite signal, thereby improving the accuracy of signal capture and tracking.

[0168] In some embodiments, the Doppler code rate offset estimation value is determined by: using a code rate offset estimation formula to determine the Doppler code rate offset estimation value; wherein the code rate offset estimation formula is:

[0169] fc1=f1·fc0 / fr

[0170] Wherein, fc1 is the estimated value of Doppler code rate offset, f1 is the estimated value of Doppler frequency deviation, fc0 is the nominal value of pseudo-random code rate, and fr is the nominal value of RF carrier frequency.

[0171] Optionally, the method for determining the Doppler frequency offset estimated value refers to step S201, which will not be described in detail here.

[0172] Step S203: Perform frequency deviation change rate compensation on the fifth satellite signal to obtain a sixth satellite signal.

[0173] In some embodiments, step S203 is implemented as follows: multiplying the fifth satellite signal by the second-order phase adjustment term to obtain the sixth satellite signal; wherein the second-order phase adjustment term is exp(-j2π·f2·t 2 / 2); where exp represents exponential operation, j is an imaginary unit, f2 is the estimated value of the Doppler frequency deviation change rate, and t is time.

[0174] In this embodiment, the second-order phase adjustment term is used to compensate for the rate of change of the frequency offset, rather than just the fixed frequency offset. This compensation can effectively handle frequency offset changes caused by acceleration or other dynamic factors. By compensating for the rate of change of the frequency offset, the phase synchronization of the signal can be maintained, and the influence of the phase error on signal processing can be reduced. By accurately compensating for the rate of change of the frequency offset, signal distortion and bit error rate can be reduced, thereby improving the quality of the received signal.

[0175] In some embodiments, the Doppler frequency offset change rate estimate is determined based on at least one of the following methods: frequency offset change rate scanning estimate, ephemeris calculation, or use of historical capture results.

[0176] Optionally, it can be determined by scanning and estimating the frequency deviation change rate, by combining ephemeris calculation with scanning and estimating the frequency deviation change rate, or by combining historical capture results with scanning and estimating the frequency deviation change rate.

[0177] In some embodiments, the method of determining the estimated value of the Doppler frequency offset change rate by using the frequency offset change rate scanning estimation is specifically implemented as follows: determining the estimated value of the Doppler frequency offset change rate by using the frequency offset change rate scanning estimation formula; wherein the frequency offset change rate scanning estimation formula is:

[0178] f2=(-N FL2 +2n2-1)·fls2 / 2,n2=1,2,...,N FL2

[0179] Among them, N FL2 is the total number of frequency deviation change rate scans, n2 is the current number of frequency deviation change rate scans, and fls2 is the frequency deviation change rate scan step.

[0180] This embodiment can systematically cover the possible frequency deviation change rate range by defining the total number of frequency deviation change rate scans and the frequency deviation change rate scan step size; the frequency deviation change rate scan estimation formula provides a simple calculation method, which generates a series of Doppler frequency deviation change rate estimation values ​​by iterating the value of n2. This method is relatively simple and easy to implement, and can be efficiently executed in hardware or software; by reasonably setting the frequency deviation change rate scan step size and the total number of frequency deviation change rate scans, this method can converge to a reasonable Doppler frequency deviation change rate estimation value in a shorter time, thereby speeding up the signal capture and processing speed.

[0181] Step S204: Compensate the code rate offset change rate of the sixth satellite signal to obtain a second satellite signal.

[0182] In some embodiments, step S204 is implemented as follows: sampling the sixth satellite signal according to a first-order time-varying sampling rate to obtain a second satellite signal; wherein the first-order time-varying sampling rate is:

[0183] fs1(t)=fs0 / fc0·(fc0+fc2·t)

[0184] Wherein, fs1(t) is the first-order time-varying sampling rate, fs0 is the zero-order time-varying sampling rate, fc0 is the nominal value of the pseudo-random code rate, t is the time, and fc2 is the estimated value of the Doppler code rate offset change rate.

[0185] This embodiment uses a first-order time-varying sampling rate to downsample the sixth satellite signal to compensate for the code rate change rate. By compensating for the code rate change rate, the receiver can better keep the pseudo-random code synchronized with the satellite signal, thereby improving the accuracy of signal capture and tracking.

[0186] In some embodiments, the Doppler code rate offset change rate estimate is determined by: using a code rate offset change rate estimate formula to determine the Doppler code rate offset change rate estimate; wherein the code rate offset change rate estimate formula is:

[0187] fc2=f2·fc0 / fr

[0188] Wherein, fc2 is the estimated value of the Doppler code rate offset change rate, f2 is the estimated value of the Doppler frequency deviation change rate, fc0 is the nominal value of the pseudo-random code rate, and fr is the nominal value of the RF carrier frequency.

[0189] Optionally, the method for determining the estimated value of the Doppler frequency offset change rate is described in step S203 and will not be described in detail herein.

[0190] In the present application, the above steps S201 to S204 provide an implementation method of Doppler effect compensation and code Doppler effect compensation. Figure 4As shown, step S102 can also be implemented as the following steps S301-S304:

[0191] Step S301: Perform frequency offset compensation on a first satellite signal to obtain a fourth satellite signal.

[0192] The implementation method of this step is the same as that of step S201 and will not be repeated here.

[0193] Step S302: Perform frequency deviation change rate compensation on the fourth satellite signal to obtain a seventh satellite signal.

[0194] The implementation method of this step is the same as that of step S203 and will not be repeated here.

[0195] Step S303: Perform code rate offset compensation on the seventh satellite signal to obtain an eighth satellite signal.

[0196] The implementation method of this step is the same as that of step S202, and will not be repeated here.

[0197] Step S304: Compensate the code rate offset change rate of the eighth satellite signal to obtain a second satellite signal.

[0198] The implementation method of this step is the same as that of step S204, and will not be repeated here.

[0199] In the present application, steps S301-S304 provide another implementation method of Doppler effect compensation and code Doppler effect compensation. Compared with the implementation method provided by steps S201-S204, the implementation method provided by steps S301-S304 adjusts the execution order of frequency deviation change rate compensation and code rate offset compensation, so that technicians in this field can choose the corresponding implementation method according to actual needs, which is more flexible.

[0200] In some embodiments, step S103 is specifically implemented as follows: intercepting a third satellite signal of the same length as the pseudo-random code signal from the position indicated by the delay estimate value in the second satellite signal; wherein the delay estimate value is determined based on a delay scan estimation formula; wherein the delay scan estimation formula is:

[0201] CNT=n3 / fsb,n3=1,2,...,Ns-N cs +1

[0202] Among them, CNT is the estimated delay value, n3 is the current delay scan times, fsb is the baseband sampling rate, Ns is the total number of sampling points of the second satellite signal, and N cs is the total number of sampling points of the pseudo-random code signal at the baseband sampling rate.

[0203] By delay compensation, the received satellite signal can be precisely aligned with the locally generated pseudo-random code signal. Accurate time synchronization can improve the signal acquisition and tracking performance and reduce errors caused by time offset. By directly intercepting the part of the signal that is equal to the pseudo-random code, the implementation of signal processing can be simplified. This method is relatively simple.

[0204] In some embodiments, Figure 5 As shown, step S105 is specifically implemented as the following steps S401-S403:

[0205] Step S401: determine a peak threshold based on the signal-to-noise ratio of the initial satellite signal.

[0206] Optionally, the signal-to-noise ratio of the initial satellite signal may be achieved by signal-to-noise ratio estimation, and the specific implementation process of the signal-to-noise ratio estimation refers to related technical means, which is not limited in this application.

[0207] The peak threshold is used to determine whether the spectrum peak meets the conditions.

[0208] In some embodiments, step S401 is specifically implemented as follows: based on the signal-to-noise ratio of the initial satellite signal, a threshold determination formula is used to determine the peak threshold; wherein the threshold determination formula is:

[0209] th=T0·K·10 NF / 10 fsc (Gn+snr Gs) / 2

[0210] Where th is the peak threshold, T0 is the noise temperature, K is the Boltzmann constant, NF is the noise factor, fsc is the digital intermediate frequency sampling rate, Gn is the noise gain, and Gs is the signal gain.

[0211] This embodiment can dynamically adjust the threshold according to the quality of the received signal by incorporating the signal-to-noise ratio into the threshold determination formula. This means that under high signal-to-noise ratio conditions, the threshold can be set higher to reduce the false detection rate; while under low signal-to-noise ratio conditions, the threshold can be lowered to improve the detection sensitivity. On this basis, combined with the noise temperature, noise coefficient, and digital intermediate frequency sampling rate of the receiver, the actual working environment and performance of the receiver can be more accurately reflected. This comprehensive consideration helps to improve the accuracy of the peak threshold. By introducing the noise gain and signal gain of the capture algorithm, the threshold calculation is more in line with the performance characteristics of the actual algorithm.

[0212] Among them, the noise gain and signal gain are determined in advance by a preset capture algorithm. When determining the peak threshold, the determined noise gain and signal gain can be directly obtained. Optionally, the preset capture algorithm includes a carrier stripping link, a distortion compensation link and a related despreading link. Among them, the implementation process of the carrier stripping link refers to step S101, which will not be repeated here. The distortion compensation link includes Doppler effect compensation, code Doppler effect compensation and delay compensation. The implementation process refers to steps S102-S103, which will not be repeated here. The implementation process of the related despreading link refers to step S104, which will not be repeated here.

[0213] In some embodiments, the process of determining the noise gain includes:

[0214] Each noise signal in the plurality of noise signals is used as an excitation source of a preset capture algorithm to determine a power ratio of each noise signal; and an average value of the power ratios of the plurality of noise signals is determined as a noise gain.

[0215] The noise signal may be a randomly generated noise signal with known power, and the number of multiple noise signals may be set according to actual needs, which is not limited in this application. The power ratio is the ratio between the maximum power of the output response signal corresponding to the noise signal and the power of the noise signal.

[0216] In this embodiment, a noise signal is input into a preset capture algorithm as an excitation source, and the preset capture algorithm is run to obtain an output response signal, the ratio between the maximum power of the output response signal and the power of the noise signal is determined, and the average value of the power ratios of multiple noise signals is determined as the noise gain.

[0217] In some embodiments, the process of determining the signal gain includes:

[0218] Each of the plurality of training signals is used as an excitation source of a preset capture algorithm to determine a power ratio of each training signal; and an average value of the power ratios of the plurality of training signals is determined as a signal gain.

[0219] Among them, the training signal is a signal that conforms to the satellite signal system, contains a pseudo-random code consistent with the local area, has a signal-to-noise ratio greater than a preset signal-to-noise ratio threshold, and has a known power. The size of the preset signal-to-noise ratio threshold can be set according to actual needs, and this application does not limit this. A signal-to-noise ratio greater than the preset signal-to-noise ratio threshold indicates that the signal-to-noise ratio of the signal is large enough, and conversely, a signal-to-noise ratio less than the preset signal-to-noise ratio threshold indicates that the signal-to-noise ratio of the signal is small. The number of multiple training signals can be set according to actual needs, and this application does not limit this.

[0220] The power ratio is the ratio between the maximum power of the output response signal corresponding to the training signal and the power of the training signal.

[0221] In this embodiment, the training signal is input into the preset capture algorithm as an excitation source, and the preset capture algorithm is run to obtain an output response signal, the ratio between the maximum power of the output response signal and the power of the training signal is determined, and the average value of the power ratios of multiple training signals is determined as the signal gain. This embodiment adopts an adaptive threshold determination method to set a peak threshold that conforms to the satellite signal system, the preset capture algorithm structure, process and parameters, so that the capture missed detection rate and the false alarm rate are controlled in a balanced state, which can improve the satellite signal capture reliability; because the peak threshold is determined more accurately, the peak detection can be performed more accurately, and the capture accuracy is improved.

[0222] Step S402: determine whether the spectrum peak exceeds a peak threshold.

[0223] If the spectrum peak value exceeds the peak threshold, step S403 is executed; if the spectrum peak value does not exceed the peak threshold, step S404 is executed.

[0224] Step S403: if the spectrum peak value exceeds the peak value threshold, it is determined that the capture result is a successful capture.

[0225] In some scenarios, in order to successfully demodulate the satellite signal, the capture algorithm needs to estimate the Doppler frequency deviation and delay of the satellite signal, and hand over the estimated parameters to the tracking algorithm for subsequent signal tracking and demodulation. Accordingly, in some embodiments, the capture result also includes a reference compensation value; the reference compensation value is used for the historical capture result, and the reference compensation value includes a reference Doppler frequency deviation, a reference Doppler frequency deviation change rate, a reference Doppler code rate offset, a reference Doppler code rate offset change rate and a reference delay.

[0226] Accordingly, after determining that the capture result is a successful capture, the satellite signal capture method provided by the present application further includes the following steps:

[0227] Determine the current delay estimate as the reference delay;

[0228] Determine the current Doppler frequency deviation change rate estimate as the reference Doppler frequency deviation change rate;

[0229] Based on the reference Doppler frequency deviation change rate, a code rate offset change rate estimation formula is used to determine the reference Doppler code rate offset change rate;

[0230] Determine the current Doppler frequency offset estimate as the first frequency offset component, and determine the second frequency offset component using a frequency offset component determination formula based on a frequency spectrum position corresponding to a frequency spectrum peak;

[0231] Determine the sum of the first frequency offset component and the second frequency offset component as a reference Doppler frequency offset;

[0232] Based on the reference Doppler frequency offset, a code rate offset estimation formula is used to determine the reference Doppler code rate offset.

[0233] Among them, the current delay estimate refers to the delay estimate currently scanned, the current Doppler frequency deviation change rate estimate refers to the Doppler frequency deviation change rate estimate currently scanned, and the current Doppler frequency deviation estimate refers to the Doppler frequency deviation estimate currently scanned. The spectrum position corresponding to the spectrum peak refers to the position of the spectrum peak in the spectrum. Optionally, after step S104, the satellite signal capture method provided by the present application also includes: recording the spectrum position corresponding to the spectrum peak, the current delay estimate, the current Doppler frequency deviation change rate estimate, the current Doppler frequency deviation estimate and other information, so as to facilitate use after determining that the capture result is a successful capture. It should be noted that other information can also be recorded for easy use, such as the power of the spectrum peak.

[0234] Optionally, based on the reference Doppler frequency deviation change rate, a code rate offset change rate estimation formula is used to determine the reference Doppler code rate offset change rate, which is specifically implemented as follows: taking the reference Doppler frequency deviation change rate as the Doppler frequency deviation change rate estimation value and inputting the code rate offset change rate estimation formula, outputting the Doppler code rate offset change rate estimation value, and determining the Doppler code rate offset change rate estimation value as the reference Doppler code rate offset change rate.

[0235] Optionally, based on the reference Doppler frequency offset, a code rate offset estimation formula is used to determine the reference Doppler code rate offset, which is specifically implemented as follows: taking the reference Doppler frequency offset as a Doppler frequency offset estimation value and inputting a code rate offset estimation formula, outputting a Doppler code rate offset estimation value, and determining the Doppler code rate offset estimation value as the reference Doppler code rate offset.

[0236] Optionally, the frequency offset component is determined by:

[0237]

[0238] Among them, fde2 is the second frequency deviation component, fsb is the baseband sampling rate, N T is the number of fast Fourier transform points, N cs is the total number of sampling points of the pseudo-random code signal at the baseband sampling rate, N F is the number of signal segments for partial matched filtering, n T is the spectrum position corresponding to the spectrum peak, mod(n T ,N T / 2) means taking n T N T / 2 is the modulo remainder.

[0239] By compensating for the distortion of satellite signals caused by Doppler frequency deviation changes of various orders and Doppler code rate offset and its various orders of changes, the Doppler frequency deviation and delay estimation errors unique to high dynamic signal capture can be reduced; in addition to estimating the frequency deviation and delay of satellite signals, the frequency deviation change rates of various orders, Doppler code rate offset and its various orders of change rates of satellite signals can also be estimated, which is more rich.

[0240] Step S404: if the spectrum peak value does not exceed the peak threshold, determining the capture result based on at least one of the current delay scanning number, the current frequency offset change rate scanning number, and the current frequency offset scanning number.

[0241] In some embodiments, determining the capture result based on at least one of the current delay scan number, the current frequency deviation change rate scan number, and the current frequency deviation scan number in step S404 includes the following steps S4041-S4043:

[0242] Step S4041, determining whether the current delayed scan times has reached an upper limit.

[0243] According to the delay scan estimation formula, the upper limit of the delay scan times is Ns-N cs +1, based on this, each delay scanning number, that is, the delay estimated values ​​corresponding to n3 from 1 to the upper limit value, can be combined into a delay set to be scanned.

[0244] Accordingly, if the current delay scanning times has reached the upper limit, it means that the delay set to be scanned has been exhausted, and then step S4043 is executed; if the current delay scanning times has not reached the upper limit, it means that the delay set to be scanned has not been exhausted, and then step S4042 is executed.

[0245] Step S4042: If the current delay scanning times have not reached the upper limit, a first loop operation is performed based on the remaining delay estimates in the delay set to be scanned until the capture result is determined to be a capture success or the current delay scanning times reaches the upper limit.

[0246] The first loop operation includes performing delay compensation on the second satellite signal based on the delay estimate corresponding to the next delay scan number in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and fast Fourier transform-based peak generation processing on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result.

[0247] For example, there are 5 delay estimation values ​​in the delay set to be scanned, the current delay scanning times is 2, and there are 3 delay estimation values ​​remaining. In the first first cycle operation, the current delay scanning times is updated to 3, and the delay estimation value corresponding to 3 is used for delay compensation to obtain a new third satellite signal, and then the correlation despreading and peak detection processing are performed; if the capture result is determined to be a successful capture, the process ends; otherwise, the second first cycle operation is entered, the current delay scanning times is updated to 4, and the delay estimation value corresponding to 4 is used for delay compensation to obtain a new third satellite signal, and then the correlation despreading and peak detection processing are performed. And so on, until the capture result is determined to be a successful capture or the current delay scanning times reaches the upper limit.

[0248] Step S4043: If the current delay scan times have reached the upper limit, determining the capture result based on at least one of the current frequency offset change rate scan times and the current frequency offset scan times.

[0249] Alternatively, step S4043 may also be replaced by: if the current delay scan times have reached the upper limit, determining that the capture result is a capture failure.

[0250] In some embodiments, determining the capture result based on at least one of the current frequency offset change rate scanning times and the current frequency offset scanning times in step S4043 includes the following steps S31 to S33:

[0251] Step S31, determining whether the current frequency deviation change rate scanning times has reached an upper limit.

[0252] According to the frequency deviation change rate scan estimation formula, the upper limit of the frequency deviation change rate scan times is N. FL2 Based on this, the estimated frequency deviation change rates corresponding to the scanning times of each frequency deviation change rate, that is, n2 from 1 to the upper limit value, can be combined into a set of frequency deviation change rates to be scanned.

[0253] Correspondingly, if the current frequency deviation change rate scanning times has reached the upper limit value, it means that the frequency deviation change rate set to be scanned has been exhausted, and then execute step S33; if the current frequency deviation change rate scanning times has not reached the upper limit value, it means that the frequency deviation change rate set to be scanned has not been exhausted, and then execute step S32.

[0254] Step S32, if the current frequency offset change rate scanning times has not reached the upper limit, a second loop operation is performed based on the remaining Doppler frequency offset change rate estimates in the frequency offset change rate set to be scanned until the capture result is determined to be a successful capture or the current frequency offset change rate scanning times reaches the upper limit.

[0255] Among them, the second loop operation includes performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal based on the Doppler frequency deviation change rate estimate corresponding to the next frequency deviation change rate scanning number in the frequency deviation change rate set to be scanned to obtain a new second satellite signal, and performing a third loop operation based on the delay estimate in the delay set to be scanned until it is determined that the capture result is successful or the current delay scanning number has reached the upper limit value.

[0256] The third loop operation includes performing delay compensation on the new second satellite signal based on the delay estimate in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and peak generation processing based on fast Fourier transform on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result.

[0257] Exemplarily, starting from the first delay estimate in the delay set to be scanned, each third loop operation uses a delay estimate in the delay set to be scanned for delay compensation, and performs related demodulation and peak detection processing until it is determined that the capture is successful or the current delay scan number has reached the upper limit, then the third loop operation is stopped.

[0258] Step S33: if the current frequency offset change rate scanning times has reached the upper limit, determining the capture result based on the current frequency offset scanning times.

[0259] Alternatively, step S33 may also be replaced by: if the current frequency deviation change rate scanning times has reached the upper limit value, determining that the capture result is a capture failure.

[0260] In some embodiments, determining the capture result based on the current frequency offset scan times in step S33 includes the following steps S331-S333:

[0261] Step S331, determining whether the current frequency offset scanning times has reached an upper limit.

[0262] According to the frequency offset scan estimation formula, the upper limit of the frequency offset scan times is N. FL1 Based on this, the estimated frequency offset values ​​corresponding to each frequency offset scanning number, that is, n1 from 1 to the upper limit value, can be combined into a frequency offset set to be scanned. Accordingly, if the current frequency offset scanning number has reached the upper limit value, it means that the frequency offset set to be scanned has been exhausted, and step S333 is executed; if the current frequency offset scanning number has not reached the upper limit value, it means that the frequency offset set to be scanned has not been exhausted, and step S332 is executed.

[0263] Step S332: If the current frequency offset scanning times does not reach the upper limit, a fourth loop operation is performed based on the remaining Doppler frequency offset estimates in the frequency offset set to be scanned, until the capture result is determined to be a successful capture or the current frequency offset scanning times reaches the upper limit.

[0264] Among them, the fourth loop operation includes compensating the Doppler effect of the first satellite signal based on the Doppler frequency deviation estimated value corresponding to the next frequency deviation scanning number in the frequency deviation set to be scanned, and performing the fifth loop operation based on the Doppler frequency deviation change rate estimated value in the frequency deviation change rate set to be scanned, until the capture result is determined to be successful capture or the current frequency deviation change rate scanning number reaches the upper limit value.

[0265] Among them, the fifth loop operation includes performing code Doppler effect compensation based on the Doppler frequency deviation change rate estimate in the frequency deviation change rate set to be scanned to obtain a new second satellite signal, and performing a sixth loop operation based on the delay estimate in the delay set to be scanned until it is determined that the capture result is successful or the current delay scan number has reached the upper limit value.

[0266] The sixth loop operation includes performing delay compensation on the new second satellite signal based on the delay estimate in the delay set to be scanned to obtain a new third satellite signal, performing partial matching filtering and peak generation processing based on fast Fourier transform on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result.

[0267] Optionally, the implementation principle of the sixth cycle operation is the same as the implementation principle of the third cycle operation, which will not be repeated here.

[0268] Step S333: If the current frequency offset scanning times have reached the upper limit, it is determined that the capture result is a capture failure.

[0269] In the satellite signal capture solution provided in this embodiment, distortion compensation is subject to feedback control of peak detection. During the peak detection process, when the spectrum peak does not exceed the peak threshold, various possible situations are tried in combination with the time delay set to be scanned, the frequency deviation change rate set to be scanned, and the frequency deviation set to be scanned. Only when the time delay set to be scanned, the frequency deviation change rate set to be scanned, and the frequency deviation set to be scanned are exhausted, is the capture result determined to be a capture failure, thereby improving the accuracy of peak detection.

[0270] See also Figure 6, which shows a flow chart of a reliable capture algorithm for high-dynamic satellite signals, and performs carrier stripping, distortion compensation, correlation despreading and peak detection on the received satellite signals in sequence. Among them, distortion compensation includes high-order time-varying phase adjustment processing and high-order time-varying sampling rate adjustment processing, and distortion compensation is also subject to feedback control of peak detection. The peak threshold used in the capture decision is determined based on the signal-to-noise ratio, which is obtained by estimating the signal-to-noise ratio of the received satellite signal. If the capture decision passes, it means that the capture is successful. If the capture decision fails, distortion compensation is performed again.

[0271] The present application inherits the fast capture and low resource consumption effects of the algorithm based on partial matched filtering and fast Fourier transform, further reduces the frequency offset estimation and delay estimation errors when the capture is successful, further improves the capture reliability, and further increases the types of Doppler effect and code Doppler parameters that can be estimated.

[0272] Combine the following Figure 7 , a specific implementation of a reliable acquisition algorithm for high-dynamic satellite signals is introduced, and the method is suitable for scenarios where the dynamics of acceleration and above can be ignored and ephemeris or historical acquisition results are not available.

[0273] Carrier stripping stage: The satellite signal is converted into a digital intermediate frequency signal through the RF front end, and a local cosine carrier and a local sine carrier are generated according to the nominal intermediate frequency. The I-channel signal of the digital intermediate frequency signal is mixed and low-pass filtered with the local cosine carrier to obtain an I-channel output signal, and the Q-channel signal of the data intermediate frequency signal is mixed and low-pass filtered according to the local sine carrier to obtain a Q-channel output signal; then, the I-channel output signal is used as the real part and the Q-channel output signal is used as the imaginary part for complexification to construct a complex baseband signal s(t).

[0274] Distortion compensation link: Doppler effect compensation, code Doppler effect compensation and time delay compensation are performed on the complex baseband signal s(t) output by the carrier stripping link. The Doppler effect to be compensated includes Doppler frequency deviation and frequency deviation change rate, and the code Doppler effect to be compensated includes code rate offset and code rate offset change rate. The order of compensation for the above five types of distortion is frequency deviation compensation, code rate offset compensation, frequency deviation change rate compensation, code rate offset change rate compensation and time delay compensation.

[0275] Frequency offset compensation is achieved by first-order time-varying phase adjustment, that is, the complex baseband signal s(t) after carrier stripping is multiplied by the phase adjustment term exp(-j2π·f1·t) to obtain the complex baseband signal s1(t), where f1 is the Doppler frequency offset estimate using frequency offset scanning estimation (parameter scanning), that is, the estimated f1 of the nth scan is:

[0276] f1=(-N FL1+2n1-1)·fls1 / 2,n1=1,2,...,N FL1

[0277] In the above formula, fls1 is the frequency deviation scanning step size, which can be set to any value less than the upper limit fdm1 of the absolute value of the Doppler frequency deviation caused by the high dynamic scene; n1 is the current frequency deviation scanning number; N FL1 is the total number of frequency deviation scans, and N FL1 Determined based on fdm1 and fls1 as follows:

[0278]

[0279] In the above formula, Indicates rounding x upwards.

[0280] Code rate offset compensation is achieved by adjusting the zero-order time-varying sampling rate, that is, the complex baseband signal s1(t) after the first-order time-varying phase adjustment is downsampled at the zero-order time-varying sampling rate fs0 at time t to obtain the complex baseband signal s2(t), where the zero-order time-varying sampling rate fs0 adopts the following structure:

[0281] fs0=fsb / fc0·(fc0+fc1)

[0282] In the above formula, fsb is the baseband sampling rate set by the receiver by default, fc0 is the nominal value of the pseudo-random code rate, and fc1 is the estimated Doppler code rate offset calculated based on the estimated Doppler frequency offset value f1, that is:

[0283] fc1=f1·fc0 / fr

[0284] In the above formula, fr is the nominal value of the RF carrier frequency.

[0285] Frequency deviation rate compensation is achieved by second-order time-varying phase adjustment, that is, the complex baseband signal s2(t) after zero-order time-varying sampling rate adjustment is multiplied by the phase adjustment term exp(-j2π·f2·t 2 / 2), and obtain the complex baseband signal s3(t), where f2 is the estimated value of the Doppler frequency deviation change rate using the frequency deviation change rate scan estimation (a kind of parameter scan), that is, the frequency deviation change rate estimated for the nth scan is:

[0286] f2=(-N FL2 +2n2-1)·fls2 / 2,n2=1,2,...,N FL2

[0287] In the above formula, fls2 is the frequency deviation change rate scanning step size, which can be set to any value less than the upper limit fdm2 of the absolute value of the Doppler frequency deviation change rate caused by high dynamic scenes; n2 is the current frequency deviation change rate scanning number, N FL2is the total number of frequency deviation change rate scans, which is determined based on fdm2 and fls2 as follows:

[0288]

[0289] In the above formula, Indicates rounding x upwards.

[0290] The code rate offset change rate compensation is implemented by first-order time-varying sampling rate adjustment, that is, the complex baseband signal s3(t) after second-order time-varying phase adjustment is downsampled at the first-order time-varying sampling rate fs1(t) at time t to obtain the complex baseband signal s4(t), wherein the first-order time-varying sampling rate fs1(t) adopts the following structure:

[0291] fs1(t)=fs0 / fc0·(fc0+fc2·t)

[0292] In the above formula, fs0 is the zero-order time-varying sampling rate, fc0 is the nominal value of the pseudo-random code rate, and fc2 is the estimated Doppler code rate offset change rate calculated based on the estimated Doppler frequency offset change rate f2, that is:

[0293] fc2=f2·fc0 / fr

[0294] In the above formula, fr is the nominal value of the RF carrier frequency.

[0295] Delay compensation: At the specified position, CNT intercepts a signal of the same length as the local pseudo-random code signal from the complex baseband signal s4(t) output by the first-order time-varying sampling rate adjustment to obtain s5(t), which is used as the input of the subsequent correlation despreading link. CNT is determined by delay scanning, that is, the estimated delay of the nth scan is:

[0296] CNT=n3 / fsb,n3=1,2,...,Ns-N cs +1

[0297] In the above formula, fsb is the baseband sampling rate set by the receiver by default, n3 is the number of current delay scans, Ns is the total number of sampling points of the complex baseband signal s4(t), and N cs is the total number of sampling points of the local pseudo-random code signal at the baseband sampling rate.

[0298] Correlation despreading link: The truncated signal s5(t) output by the distortion compensation link is subjected to PMF processing and peak generation processing based on FFT processing.

[0299] PMF processing uses the locally generated pseudo-random code signal to conjugate multiply the input truncated signal, and then divides the conjugate multiplication output signal evenly into N F Segments, sum each segment of the signal, and get a sampling point length of N F The output signal.

[0300] N F It is determined by the frequency offset scanning step length fls1 of the distortion compensation link, that is, Among them, N cs is the total number of sampling points of the local pseudo-random code signal at the baseband sampling rate, Indicates rounding x upwards, where fsb is the default baseband sampling rate of the receiver.

[0301] Peak generation processing, the length of the output of the above PMF processing process is N F The signal is N T Point FFT, the sampling point length is N T The spectrum is then searched for the maximum value point in the obtained spectrum, which is also the spectrum peak, and the corresponding five parameters are recorded, namely the power of the maximum value point, the spectrum position of the maximum value point, the frequency deviation scanned by the current distortion compensation link, the frequency deviation change rate, and the delay, as the input of the subsequent peak detection link. Among them, N T According to the number of signal segments N in PMF processing F Determined as follows:

[0302]

[0303] Among them, lb() represents the logarithmic function with base 2, Indicates rounding x upwards.

[0304] In the peak detection link, the signal-to-noise ratio is obtained through signal-to-noise ratio estimation, and the peak threshold is determined according to the signal-to-noise ratio. The peak threshold is used to capture and judge the spectrum peak output by the relevant despreading link.

[0305] In the first case, if the spectrum peak exceeds the peak threshold, the judgment is passed and the capture is determined to be successful. Subsequently, the Doppler frequency deviation, frequency deviation change rate, code rate offset, code rate offset change rate, and delay are estimated based on the recorded parameters.

[0306] In the second case, if the spectrum peak value does not exceed the peak value threshold, the judgment fails, and it is further determined whether the set of delays to be scanned preset in the distortion compensation link is exhausted.

[0307] If the delay set to be scanned is not exhausted, the next delay estimate value in the delay set to be scanned is taken to adjust the sliding window for data interception, and the data is intercepted again and the correlation despreading and peak detection processing are performed;

[0308] If the set of time delays to be scanned has been exhausted, it is determined whether the set of preset frequency deviation change rates to be scanned has been exhausted.

[0309] If the set of frequency offset change rates to be scanned is not exhausted, then the next frequency offset change rate estimate in the set of frequency offset change rates to be scanned is taken, and the frequency offset change rate estimate is used to sequentially perform second-order time-varying phase adjustment and first-order time-varying sampling rate adjustment, and data is intercepted again from the first delay estimate in the set of delays to be scanned and correlation despreading and peak detection processing are performed;

[0310] If the set of frequency offset change rates to be scanned has been exhausted, it is determined whether the preset set of frequency offsets to be scanned has been exhausted.

[0311] If the frequency offset set to be scanned is not exhausted, then the next frequency offset estimated value in the frequency offset set to be scanned is taken, and the first-order time-varying phase adjustment and the zero-order time-varying sampling rate adjustment are performed in sequence using the frequency offset estimated value, and the first frequency offset change rate estimated value in the frequency offset change rate set to be scanned is taken again, and the second-order time-varying phase adjustment and the first-order time-varying sampling rate adjustment are performed in sequence using the frequency offset change rate value, and then data is intercepted starting from the first time delay value in the time delay set to be scanned and correlation despreading and peak detection processing are performed;

[0312] If the set of frequency offsets to be scanned has been exhausted, it is determined that the capture has failed.

[0313] This application also provides Figure 7 A variation of the specific embodiment shown, such as Figure 8 As shown. Figure 7 Compared with the specific implementation manner shown, Figure 8 The specific implementation method shown adjusts the order of each order of time-varying phase adjustment and each order of time-varying sampling rate adjustment in the distortion compensation link, that is, firstly perform the first-order time-varying phase adjustment and the second-order time-varying phase adjustment, and then perform the zero-order time-varying sampling rate adjustment and the first-order time-varying sampling rate adjustment in sequence.

[0314] Figure 8 In the specific implementation mode shown, in the peak detection link, when the capture judgment fails and the set of delays to be scanned has been exhausted, the control flow is adjusted as follows:

[0315] Determining whether the preset set of frequency deviation change rates to be scanned is exhausted;

[0316] If the set of frequency deviation change rates to be scanned is not exhausted, then the next frequency deviation change rate estimate value in the set of frequency deviation change rates to be scanned is taken, and the frequency deviation change rate estimate value is used to sequentially perform second-order time-varying phase adjustment, zero-order time-varying sampling rate adjustment, and first-order time-varying sampling rate adjustment, and data is intercepted again from the first time delay estimate value in the time delay set to be scanned and correlation despreading and peak detection processing are performed;

[0317] If the set of frequency offset change rates to be scanned has been exhausted, determining whether the preset set of frequency offsets to be scanned has been exhausted;

[0318] If the frequency offset set to be scanned is not exhausted, then the next frequency offset estimated value in the frequency offset set to be scanned is taken, and the frequency offset estimated value is used to perform a first-order time-varying phase adjustment, and the first frequency offset change rate estimated value in the frequency offset change rate set to be scanned is taken again, and the frequency offset change rate estimated value is used to perform a second-order time-varying phase adjustment, a zero-order time-varying sampling rate adjustment, and a first-order time-varying sampling rate adjustment, and then data is intercepted starting from the first time delay estimated value in the time delay set to be scanned and correlation demodulation and peak detection processing are performed;

[0319] If the set of frequency offsets to be scanned has been exhausted, the capture fails.

[0320] Combine the following Fig. 9 , another specific implementation of a reliable acquisition algorithm for high-dynamic satellite signals is introduced, and this method is suitable for scenarios where the dynamics of acceleration and above can be ignored and ephemeris calculation or historical acquisition results are available.

[0321] In the carrier stripping stage, the satellite signal is converted into a digital intermediate frequency signal through the RF front end, and a local cosine carrier and a local sine carrier are generated according to the nominal intermediate frequency. The I-channel signal of the digital intermediate frequency signal is mixed and low-pass filtered with the local cosine carrier to obtain an I-channel output signal, and the Q-channel signal of the data intermediate frequency signal is mixed and low-pass filtered according to the local sine carrier to obtain a Q-channel output signal; then, the signal is complexified with the I-channel output signal as the real part and the Q-channel output signal as the imaginary part to construct a complex baseband signal s(t).

[0322] The distortion compensation link performs Doppler effect compensation, code Doppler effect compensation and time delay compensation on the complex baseband signal s(t) output by the carrier stripping link, wherein the Doppler effect to be compensated includes Doppler frequency deviation and frequency deviation change rate, and the code Doppler effect to be compensated includes code rate offset and code rate offset change rate; the compensation for the above five types of distortions is carried out in the order of frequency deviation compensation, code rate offset compensation, frequency deviation change rate compensation, code rate offset change rate compensation and time delay compensation.

[0323] Frequency offset compensation is achieved by first-order time-varying phase adjustment, that is, the complex baseband signal s(t) after carrier stripping is multiplied by the phase adjustment term exp(-j2π·f1·t) to obtain the complex baseband signal s1(t), where f1 is the Doppler frequency offset estimated based on the recent historical capture results of the same satellite and the same frequency point signal, or estimated based on the ephemeris and the approximate position and velocity of the receiver.

[0324] Code rate offset compensation is achieved by adjusting the zero-order time-varying sampling rate, that is, the complex baseband signal s1(t) after the first-order time-varying phase adjustment is downsampled at the zero-order time-varying sampling rate fs0 at time t to obtain the complex baseband signal s2(t), where the zero-order time-varying sampling rate fs0 adopts the following structure:

[0325] fs0=fsb / fc0·(fc0+fc1)

[0326] In the above formula, fsb is the baseband sampling rate set by the receiver by default, fc0 is the nominal value of the pseudo-random code rate, and fc1 is the Doppler code rate offset estimate calculated based on the Doppler frequency offset estimate f1, that is:

[0327] fc1=f1·fc0 / fr

[0328] In the above formula, fr is the nominal value of the RF carrier frequency.

[0329] Frequency deviation rate compensation is achieved by using second-order time-varying phase adjustment, that is, the complex baseband signal s2(t) after zero-order time-varying sampling rate adjustment is multiplied by the phase adjustment term exp(-j2π·f2·t 2 / 2), and obtain the complex baseband signal s3(t), where f2 is the estimated Doppler frequency deviation change rate, which is determined by the combination of ephemeris calculation or the most recent historical capture result and parameter scanning, that is:

[0330]

[0331] In the above formula, fls2 is the Doppler frequency deviation change rate estimated based on the most recent historical capture results of the same satellite and frequency signal, or estimated based on the ephemeris and the approximate position and acceleration of the receiver. fls2 is the frequency deviation change rate scan step size, which can be set to less than The uncertainty Δf2 is any value; n2 is the number of sweeps of the current frequency deviation change rate, N FL2 is the total number of sweeps of the frequency deviation change rate, which is determined according to Δf2 and fls2 as follows:

[0332]

[0333] In the above formula, Indicates rounding x upwards.

[0334] The code rate offset change rate compensation is implemented by first-order time-varying sampling rate adjustment, that is, the complex baseband signal s3(t) after second-order time-varying phase adjustment is downsampled at the first-order time-varying sampling rate fs1(t) at time t to obtain the complex baseband signal s4(t), wherein the first-order time-varying sampling rate fs1(t) adopts the following structure:

[0335] fs1(t)=fs0 / fc0·(fc0+fc2·t)

[0336] In the above formula, fs0 is the zero-order time-varying sampling rate, fc0 is the nominal value of the pseudo-random code rate, and fc2 is the code Doppler rate offset estimate calculated based on the Doppler frequency offset estimate f2, that is:

[0337] fc2=f2·fc0 / fr

[0338] In the above formula, fr is the nominal value of the RF carrier frequency.

[0339] Delay compensation: At the specified position CNT, a signal of the same length as the local pseudo-random code signal is intercepted from the complex baseband signal s4(t) output by the first-order time-varying sampling rate adjustment to obtain the complex baseband signal s5(t), which is used as the input of the subsequent related despreading link. CNT is determined by delay scanning, that is, the estimated delay of the nth scan is:

[0340] CNT=n3 / fsb,n3=1,2,...,Ns-N cs +1

[0341] In the above formula, fsb is the baseband sampling rate set by the receiver by default, n3 is the number of current delay scans, Ns is the total number of sampling points of the complex baseband signal s4(t), and N cs is the total number of sampling points of the local pseudo-random code signal at the baseband sampling rate.

[0342] Correlation despreading link: The truncated signal s5(t) output by the distortion compensation link is subjected to PMF processing and peak generation processing based on FFT processing.

[0343] PMF processing uses the locally generated pseudo-random code signal to conjugate multiply the input truncated signal, and then divides the conjugate multiplication output signal evenly into N F Segments, sum each segment of the signal, and get a sampling point length of N F The output signal.

[0344] N F It is determined by the estimated uncertainty Δf of the frequency offset of the distortion compensation link, that is, Among them, N cs is the total number of sampling points of the local pseudo-random code signal at the baseband sampling rate, Indicates rounding x upwards, where fsb is the default baseband sampling rate of the receiver.

[0345] Peak generation processing, the length of the output of the above PMF processing process is N F Signal as N T Point FFT, the sampling point length is N T The spectrum is then searched for the maximum value point in the obtained spectrum, which is also the spectrum peak, and the corresponding five parameters are recorded, namely the power of the maximum value point, the spectrum position of the maximum value point, the frequency deviation scanned by the current distortion compensation link, the frequency deviation change rate, and the delay, as the input of the subsequent peak detection link. Among them, N T According to the number of signal segments N in PMF processing F Determined as follows:

[0346]

[0347] Among them, lb() represents the logarithmic function with base 2, Indicates rounding x upwards.

[0348] In the peak detection link, the signal-to-noise ratio is obtained through signal-to-noise ratio estimation, and the peak threshold is determined according to the signal-to-noise ratio. The peak threshold is used to capture and judge the spectrum peak output by the relevant despreading link.

[0349] In the first case, if the spectrum peak exceeds the peak threshold, the judgment is passed and the capture is determined to be successful. Subsequently, the Doppler frequency deviation, frequency deviation change rate, code rate offset, code rate offset change rate, and delay are estimated based on the recorded parameters.

[0350] In the second case, if the spectrum peak value does not exceed the peak value threshold, the judgment fails, and it is further determined whether the set of delays to be scanned preset in the distortion compensation link is exhausted.

[0351] If the set of delays to be scanned is not exhausted, the next delay estimate value in the set of delays to be scanned is taken to adjust the sliding window for data capture, and the data is captured again and related despreading and peak detection are performed.

[0352] If the set of time delays to be scanned has been exhausted, it is determined whether the set of preset frequency deviation change rates to be scanned has been exhausted.

[0353] If the set of frequency offset change rates to be scanned is not exhausted, then the next frequency offset change rate estimate in the set of frequency offset change rates to be scanned is taken, and the frequency offset change rate estimate is used to sequentially perform second-order time-varying phase adjustment and first-order time-varying sampling rate adjustment, and data is intercepted again from the first delay estimate in the set of delays to be scanned and correlation despreading and peak detection processing are performed;

[0354] If the set of frequency deviation change rates to be scanned has been exhausted, the capture fails.

[0355] This application also provides Fig. 9 A variation of the specific embodiment shown, such as Fig.10 As shown. Fig. 9 Compared with the specific implementation manner shown in FIG. Fig.10 The specific implementation method shown adjusts the order of each order of time-varying phase adjustment and each order of time-varying sampling rate adjustment in the distortion compensation link, that is, firstly perform the first-order time-varying phase adjustment and the second-order time-varying phase adjustment, and then perform the zero-order time-varying sampling rate adjustment and the first-order time-varying sampling rate adjustment in sequence.

[0356] Fig.10 In the specific implementation mode shown, in the peak detection link, when the capture judgment fails and the set of delays to be scanned has been exhausted, the control flow is adjusted as follows:

[0357] Determining whether the preset set of frequency deviation change rates to be scanned is exhausted;

[0358] If the set of frequency offset change rates to be scanned is not exhausted, then the next frequency offset change rate estimate in the set of frequency offset change rates to be scanned is taken, and the frequency offset change rate estimate is used to perform second-order time-varying phase adjustment, zero-order time-varying sampling rate adjustment and first-order time-varying sampling rate adjustment in sequence, and data is intercepted again starting from the first delay estimate in the set of delays to be scanned for correlation demodulation and peak detection processing; if the set of frequency offset change rates to be scanned has been exhausted, the capture fails.

[0359] Fig.11 is a schematic diagram of the structure of a satellite signal acquisition device provided by the present application, such as Fig.11 As shown, in this embodiment, the satellite signal acquisition device 50 can be set in an electronic device, and the satellite signal acquisition device 50 includes:

[0360] The carrier stripping module 501 is used to strip the carrier of the received initial satellite signal to obtain a first satellite signal;

[0361] A Doppler compensation module 502, configured to perform Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal;

[0362] A delay compensation module 503, configured to perform delay compensation on the second satellite signal to obtain a third satellite signal;

[0363] A correlation despreading module 504 is used to perform partial matched filtering and peak generation processing based on fast Fourier transform on the third satellite signal to obtain a spectrum peak;

[0364] The peak detection module 505 is used to perform peak detection based on the spectrum peak to obtain a capture result; the capture result indicates capture success or capture failure.

[0365] In some embodiments, Doppler effect compensation includes frequency offset compensation and frequency offset change rate compensation, and code Doppler effect compensation includes code rate offset compensation and code rate offset change rate compensation; Doppler compensation module 502 includes:

[0366] a frequency offset compensation unit, configured to perform frequency offset compensation on the first satellite signal to obtain a fourth satellite signal;

[0367] a code rate offset compensation unit, configured to perform code rate offset compensation on the fourth satellite signal to obtain a fifth satellite signal;

[0368] a frequency deviation change rate compensation unit, configured to perform frequency deviation change rate compensation on the fifth satellite signal to obtain a sixth satellite signal;

[0369] The code rate offset change rate compensation unit is used to perform code rate offset change rate compensation on the sixth satellite signal to obtain a second satellite signal.

[0370] In some embodiments, the frequency offset compensation unit is configured to:

[0371] The first satellite signal is multiplied by a first-order phase adjustment term to obtain a fourth satellite signal; the first-order phase adjustment term is exp(-j2π·f1·t);

[0372] Wherein, exp represents exponential operation, j is an imaginary unit, f1 is the estimated value of Doppler frequency offset, and t is time.

[0373] In some embodiments, the Doppler frequency offset estimation value is determined based on at least one of the following methods: frequency offset scanning estimation, ephemeris calculation, or use of historical acquisition results.

[0374] In some embodiments, a frequency offset scanning estimation module is further included, which is used to: determine the Doppler frequency offset estimation value by using a frequency offset scanning estimation formula; the frequency offset scanning estimation formula is:

[0375] f1=(-N FL1 +2n1-1)·fls1 / 2,n1=1,2,...,N FL1

[0376] Among them, N FL1 is the total number of frequency offset scans, n1 is the current number of frequency offset scans, and fls1 is the frequency offset scan step.

[0377] In some embodiments, the code rate offset compensation unit is used to: sample the fourth satellite signal according to a zero-order time-varying sampling rate to obtain a fifth satellite signal; the zero-order time-varying sampling rate is:

[0378] fs0=fsb / fc0·(fc0+fc1)

[0379] Wherein, fs0 is the zero-order time-varying sampling rate, fsb is the baseband sampling rate, fc0 is the nominal value of the pseudo-random code rate, and fc1 is the estimated value of the Doppler code rate offset.

[0380] In some embodiments, the code rate offset compensation unit is further configured to:

[0381] The Doppler code rate offset estimation formula is used to determine the Doppler code rate offset estimation value; the code rate offset estimation formula is:

[0382] fc1=f1·fc0 / fr

[0383] Wherein, fc1 is the estimated value of Doppler code rate offset, f1 is the estimated value of Doppler frequency deviation, fc0 is the nominal value of pseudo-random code rate, and fr is the nominal value of RF carrier frequency.

[0384] In some embodiments, the frequency deviation change rate compensation unit is used to: multiply the fifth satellite signal by the second-order phase adjustment term to obtain the sixth satellite signal; the second-order phase adjustment term is exp(-j2π·f2·t 2 / 2);

[0385] Wherein, exp represents exponential operation, j is an imaginary unit, f2 is the estimated value of the Doppler frequency deviation change rate, and t is time.

[0386] In some embodiments, the Doppler frequency offset change rate estimate is determined based on at least one of the following methods: frequency offset change rate scanning estimate, ephemeris calculation, or use of historical capture results.

[0387] In some embodiments, a frequency deviation change rate scanning and prediction module is further included, which is used to: determine the Doppler frequency deviation change rate estimation value by using a frequency deviation change rate scanning and prediction formula; the frequency deviation change rate scanning and prediction formula is:

[0388] f2=(-N FL2 +2n2-1)·fls2 / 2,n2=1,2,...,N FL2

[0389] Among them, N FL2 is the total number of frequency deviation change rate scans, n2 is the current number of frequency deviation change rate scans, and fls2 is the frequency deviation change rate scan step.

[0390] In some embodiments, the code rate offset change rate compensation unit is used to: sample the sixth satellite signal according to a first-order time-varying sampling rate to obtain a second satellite signal; the first-order time-varying sampling rate is:

[0391] fs1(t)=fs0 / fc0·(fc0+fc2·t)

[0392] Wherein, fs1(t) is the first-order time-varying sampling rate, fs0 is the zero-order time-varying sampling rate, fc0 is the nominal value of the pseudo-random code rate, t is the time, and fc2 is the estimated value of the Doppler code rate offset change rate.

[0393] In some embodiments, the code rate offset change rate compensation unit is further used to: determine the Doppler code rate offset change rate estimate value by using a code rate offset change rate estimate formula; the code rate offset change rate estimate formula is:

[0394] fc2=f2·fc0 / fr

[0395] Wherein, fc2 is the estimated value of the Doppler code rate offset change rate, f2 is the estimated value of the Doppler frequency deviation change rate, fc0 is the nominal value of the pseudo-random code rate, and fr is the nominal value of the RF carrier frequency.

[0396] In some embodiments, Doppler effect compensation includes frequency offset compensation and frequency offset change rate compensation, and code Doppler effect compensation includes code rate offset compensation and code rate offset change rate compensation; Doppler compensation module 502 includes:

[0397] a frequency offset compensation unit, configured to perform frequency offset compensation on the first satellite signal to obtain a fourth satellite signal;

[0398] a frequency deviation change rate compensation unit, configured to perform frequency deviation change rate compensation on the fourth satellite signal to obtain a seventh satellite signal;

[0399] a code rate offset compensation unit, configured to perform code rate offset compensation on the seventh satellite signal to obtain an eighth satellite signal;

[0400] The code rate offset change rate compensation unit is used to perform code rate offset change rate compensation on the eighth satellite signal to obtain a second satellite signal.

[0401] In some embodiments, the delay compensation module 503 is used to: intercept a third satellite signal of the same length as the pseudo-random code signal from the position indicated by the delay estimate value in the second satellite signal; the delay estimate value is determined based on the delay scanning estimate formula; the delay scanning estimate formula is:

[0402] CNT=n3 / fsb,n3=1,2,...,Ns-N cs +1

[0403] Among them, CNT is the estimated delay value, n3 is the current delay scan times, fsb is the baseband sampling rate, Ns is the total number of sampling points of the second satellite signal, and N cs is the total number of sampling points of the pseudo-random code signal at the baseband sampling rate.

[0404] In some embodiments, the peak detection module 505 includes:

[0405] A threshold determination unit, configured to determine a peak threshold based on a signal-to-noise ratio of an initial satellite signal;

[0406] A detection unit, configured to determine a capture result based on at least one of a current delay scan number, a current frequency deviation change rate scan number, and a current frequency deviation scan number if the spectrum peak value does not exceed the peak threshold value;

[0407] The detection unit is further configured to determine that the capture result is a successful capture if the spectrum peak value exceeds the peak value threshold.

[0408] In some embodiments, the threshold determination unit is configured to:

[0409] Based on the signal-to-noise ratio of the initial satellite signal, the peak threshold is determined using the threshold determination formula; the threshold determination formula is:

[0410] th=T0·K·10 NF / 10 fsc (Gn+snr Gs) / 2

[0411] Where th is the peak threshold, T0 is the noise temperature, K is the Boltzmann constant, NF is the noise factor, fsc is the digital intermediate frequency sampling rate, Gn is the noise gain, and Gs is the signal gain.

[0412] In some embodiments, the system further includes a noise gain determination module for:

[0413] Using each of the multiple noise signals as an excitation source of a preset capture algorithm, determining a power ratio of each noise signal; the power ratio is a ratio between a maximum power of an output response signal corresponding to the noise signal and a power of the noise signal;

[0414] The average value of the power ratios of the plurality of noise signals is determined as the noise gain.

[0415] In some embodiments, the method further includes a signal gain determination module for:

[0416] Using each of the multiple training signals as an excitation source of a preset capture algorithm, a power ratio of each training signal is determined; the power ratio is the ratio between the maximum power of the output response signal corresponding to the training signal and the power of the training signal; the training signal is a signal that conforms to the satellite signal system, contains a pseudo-random code consistent with the local, and has a signal-to-noise ratio greater than a preset signal-to-noise ratio threshold;

[0417] An average value of the power ratios of the plurality of training signals is determined as the signal gain.

[0418] In some embodiments, the detection unit, when determining the capture result based on at least one of the current delay scan number, the current frequency offset change rate scan number, and the current frequency offset scan number, is configured to:

[0419] Determine whether the current delay scan times has reached the upper limit;

[0420] If the current delay scan number does not reach the upper limit, a first loop operation is performed based on the remaining delay estimate values ​​in the delay set to be scanned until it is determined that the capture result is successful capture or the current delay scan number reaches the upper limit; the first loop operation includes performing delay compensation on the second satellite signal based on the delay estimate value corresponding to the next delay scan number in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and fast Fourier transform-based peak generation processing on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result;

[0421] If the current delay scan times have reached the upper limit, the capture result is determined to be a capture failure, or the capture result is determined based on at least one of the current frequency offset change rate scan times and the current frequency offset scan times.

[0422] In some embodiments, the detection unit, when determining the capture result based on at least one of the current frequency offset change rate scanning number and the current frequency offset scanning number, is configured to:

[0423] Determine whether the current frequency deviation change rate scanning times has reached the upper limit;

[0424] If the current number of frequency offset change rate scans does not reach the upper limit, a second loop operation is performed based on the remaining Doppler frequency offset change rate estimates in the frequency offset change rate set to be scanned until it is determined that the capture result is successful or the current number of frequency offset change rate scans reaches the upper limit; the second loop operation includes performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal based on the Doppler frequency offset change rate estimate corresponding to the next number of frequency offset change rate scans in the frequency offset change rate set to be scanned to obtain a new second satellite signal, and performing a third loop operation based on the delay estimate in the delay set to be scanned until it is determined that the capture result is successful or the current number of delay scans has reached the upper limit; the third loop operation includes performing delay compensation on the new second satellite signal based on the delay estimate in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and peak generation processing based on fast Fourier transform on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result;

[0425] If the current number of frequency offset change rate scans has reached the upper limit, the capture result is determined to be a capture failure, or the capture result is determined based on the current number of frequency offset scans.

[0426] In some embodiments, the detection unit, when determining the capture result based on the current frequency offset scanning number, is configured to:

[0427] Determine whether the current frequency deviation scanning times has reached the upper limit;

[0428] If the current number of frequency offset scans has not reached the upper limit, a fourth loop operation is performed based on the remaining Doppler frequency offset estimates in the frequency offset set to be scanned until the capture result is determined to be a successful capture or the current number of frequency offset scans reaches the upper limit; the fourth loop operation includes performing Doppler effect compensation on the first satellite signal based on the Doppler frequency offset estimate corresponding to the next frequency offset scan number in the frequency offset set to be scanned, and performing a fifth loop operation based on the Doppler frequency offset change rate estimate in the frequency offset change rate set to be scanned until the capture result is determined to be a successful capture or the current number of frequency offset change rate scans reaches the upper limit; the fifth loop operation includes performing Doppler effect compensation on the first satellite signal based on the Doppler frequency offset estimate corresponding to the next frequency offset scan number in the frequency offset change rate set to be scanned The method further comprises: performing code Doppler effect compensation on the Doppler frequency deviation change rate estimate in the rate set to obtain a new second satellite signal, and performing a sixth loop operation based on the delay estimate in the delay set to be scanned, until it is determined that the capture result is successful capture or the current delay scan number has reached an upper limit; the sixth loop operation includes performing delay compensation on the new second satellite signal based on the delay estimate in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and fast Fourier transform-based peak generation processing on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result;

[0429] If the current frequency deviation scanning times has reached the upper limit, the capture result is determined to be a capture failure.

[0430] In some embodiments, the capture result further includes a reference compensation value; the reference compensation value is used for the historical capture result, and the reference compensation value includes a reference Doppler frequency deviation, a reference Doppler frequency deviation change rate, a reference Doppler code rate offset, a reference Doppler code rate offset change rate and a reference delay;

[0431] The detection unit, after determining that the capture result is a capture success, is further used to:

[0432] Determine the current delay estimate as the reference delay;

[0433] Determine the current Doppler frequency deviation change rate estimate as the reference Doppler frequency deviation change rate;

[0434] Based on the reference Doppler frequency deviation change rate, a code rate offset change rate estimation formula is used to determine the reference Doppler code rate offset change rate;

[0435] Determine the current Doppler frequency offset estimate as the first frequency offset component, and determine the second frequency offset component using a frequency offset component determination formula based on a frequency spectrum position corresponding to a frequency spectrum peak;

[0436] Determine the sum of the first frequency offset component and the second frequency offset component as a reference Doppler frequency offset;

[0437] Based on the reference Doppler frequency offset, a code rate offset estimation formula is used to determine the reference Doppler code rate offset.

[0438] The satellite signal acquisition device 50 provided in this embodiment can execute the technical solution of the corresponding method embodiment. Its implementation principle and technical effect are similar to those of the corresponding method embodiment, and will not be repeated here.

[0439] An embodiment of the present application also provides an electronic device. Fig.12 Schematic diagram of the structure of an electronic device provided by this application. Fig.12 As shown, the electronic device 60 includes: a processor 601 and a memory 602 communicatively connected to the processor 601 .

[0440] The memory 602 stores computer-executable instructions; the processor 601 executes the computer-executable instructions stored in the memory 602 to implement the satellite signal acquisition method provided in the present application.

[0441] In the embodiment of the present application, the memory 602 and the processor 601 are connected via a bus. The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc.

[0442] The components, their connections and relationships, and their functions shown herein are only examples and are not intended to limit the implementation of the present application described and / or required herein. The various components are interconnected using different buses and can be installed on a common motherboard or in other ways as needed.

[0443] In an exemplary embodiment, a computer-readable storage medium is also provided, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the satellite signal acquisition method provided in the present application.

[0444] In an exemplary embodiment, a computer program product is also provided, including a computer program. When the computer program in the computer program product is executed by a processor, it is used to implement the satellite signal acquisition method provided in the present application.

[0445] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the claims.

[0446] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A satellite signal acquisition method, characterized in that: include: Carrier stripping is performed on the received initial satellite signal to obtain a first satellite signal; Performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal; Performing time delay compensation on the second satellite signal to obtain a third satellite signal; Performing partial matched filtering and fast Fourier transform-based peak generation processing on the third satellite signal to obtain a spectrum peak; Perform peak detection based on the spectrum peak to obtain a capture result; The capture result indicates capture success or capture failure.

2. The method according to claim 1, characterized in that The Doppler effect compensation includes frequency offset compensation and frequency offset change rate compensation, and the code Doppler effect compensation includes code rate offset compensation and code rate offset change rate compensation; performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal includes: Performing frequency offset compensation on the first satellite signal to obtain a fourth satellite signal; Performing code rate offset compensation on the fourth satellite signal to obtain a fifth satellite signal; performing frequency deviation change rate compensation on the fifth satellite signal to obtain a sixth satellite signal; The code rate offset change rate compensation is performed on the sixth satellite signal to obtain a second satellite signal.

3. The method according to claim 2, characterized in that The performing frequency offset compensation on the first satellite signal to obtain a fourth satellite signal includes: Multiplying the first satellite signal by a first-order phase adjustment term to obtain a fourth satellite signal; the first-order phase adjustment term is exp(-j2π·f1·t); Wherein, exp represents exponential operation, j is an imaginary unit, f1 is the estimated value of Doppler frequency offset, and t is time.

4. The method according to claim 3, characterized in that The Doppler frequency offset estimation value is determined based on at least one of the following methods: frequency offset scanning estimation, ephemeris calculation or use of historical capture results.

5. The method according to claim 4, characterized in that The frequency offset scanning estimation includes: The Doppler frequency offset estimation formula is used to determine the Doppler frequency offset estimation value; the frequency offset scanning estimation formula is: f1=(-N FL1 +2n1-1)·fls1 / 2,n1=1,2,...,N FL1 Among them, N FL1 is the total number of frequency offset scans, n1 is the current number of frequency offset scans, and fls1 is the frequency offset scan step.

6. The method according to claim 2, characterized in that The performing code rate offset compensation on the fourth satellite signal to obtain a fifth satellite signal includes: The fourth satellite signal is sampled according to a zero-order time-varying sampling rate to obtain a fifth satellite signal; the zero-order time-varying sampling rate is: fs0=fsb / fc0·(fc0+fc1) Wherein, fs0 is the zero-order time-varying sampling rate, fsb is the baseband sampling rate, fc0 is the nominal value of the pseudo-random code rate, and fc1 is the estimated value of the Doppler code rate offset.

7. The method according to claim 6, characterized in that Also includes: The Doppler code rate offset estimation formula is used to determine the Doppler code rate offset estimation value; the code rate offset estimation formula is: fc1=f1·fc0 / fr Wherein, fc1 is the estimated value of Doppler code rate offset, f1 is the estimated value of Doppler frequency deviation, fc0 is the nominal value of pseudo-random code rate, and fr is the nominal value of RF carrier frequency.

8. The method according to claim 2, characterized in that: The performing frequency deviation change rate compensation on the fifth satellite signal to obtain a sixth satellite signal includes: The fifth satellite signal is multiplied by a second-order phase adjustment term to obtain a sixth satellite signal; the second-order phase adjustment term is exp(-j2πf2·t 2 / 2); Wherein, exp represents exponential operation, j is an imaginary unit, f2 is the estimated value of the Doppler frequency deviation change rate, and t is time.

9. The method according to claim 8, characterized in that The Doppler frequency offset change rate estimate is determined based on at least one of the following methods: frequency offset change rate scanning estimate, ephemeris calculation, or use of historical capture results.

10. The method according to claim 9, characterized in that The frequency deviation change rate scanning and estimation includes: The Doppler frequency deviation change rate estimation value is determined by using a frequency deviation change rate scanning estimation formula; the frequency deviation change rate scanning estimation formula is: <h2 style=";text-align:left;direction:ltr">f2=(-N<h2 style=";text-align:left;direction:ltr"> FL2 <h2 style=";text-align:left;direction:ltr"> +2n2-1)·fls2 / 2,n2 = 1,2,...,N<h2 style=";text-align:left;direction:ltr"> FL2 Among them, N FL2 is the total number of frequency deviation change rate scans, n2 is the current number of frequency deviation change rate scans, and fls2 is the frequency deviation change rate scan step.

11. The method according to claim 2, characterized in that The performing code rate offset change rate compensation on the sixth satellite signal to obtain a second satellite signal includes: The sixth satellite signal is sampled according to a first-order time-varying sampling rate to obtain a second satellite signal; the first-order time-varying sampling rate is: fs1(t)=fs0 / fc0·(fc0+fc2·t) Wherein, fs1(t) is the first-order time-varying sampling rate, fs0 is the zero-order time-varying sampling rate, fc0 is the nominal value of the pseudo-random code rate, t is the time, and fc2 is the estimated value of the Doppler code rate offset change rate.

12. The method according to claim 11, characterized in that Also includes: The Doppler code rate offset change rate estimation formula is used to determine the Doppler code rate offset change rate estimation value; the code rate offset change rate estimation formula is: fc2=f2·fc0 / fr Wherein, fc2 is the estimated value of the Doppler code rate offset change rate, f2 is the estimated value of the Doppler frequency deviation change rate, fc0 is the nominal value of the pseudo-random code rate, and fr is the nominal value of the RF carrier frequency.

13. The method according to claim 1, characterized in that The Doppler effect compensation includes frequency offset compensation and frequency offset change rate compensation, and the code Doppler effect compensation includes code rate offset compensation and code rate offset change rate compensation; performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal includes: Performing frequency offset compensation on the first satellite signal to obtain a fourth satellite signal; performing frequency deviation change rate compensation on the fourth satellite signal to obtain a seventh satellite signal; performing code rate offset compensation on the seventh satellite signal to obtain an eighth satellite signal; The eighth satellite signal is compensated for a code rate offset change rate to obtain a second satellite signal.

14. The method according to claim 1, characterized in that The performing delay compensation on the second satellite signal to obtain a third satellite signal includes: A third satellite signal having the same length as the pseudo-random code signal is intercepted from a position indicated by the estimated delay value in the second satellite signal; the estimated delay value is determined based on a delay scan estimation formula; the delay scan estimation formula is: CNT=n3 / fsb,n3=1,2,...,Ns-N cs +1 Wherein, CNT is the estimated delay value, n3 is the current delay scan times, fsb is the baseband sampling rate, Ns is the total number of sampling points of the second satellite signal, and N cs is the total number of sampling points of the pseudo-random code signal at the baseband sampling rate.

15. The method according to claim 1, characterized in that The performing peak detection based on the spectrum peak to obtain a capture result includes: Determining a peak threshold based on a signal-to-noise ratio of the initial satellite signal; If the spectrum peak value does not exceed the peak threshold, determining a capture result based on at least one of the current delay scan number, the current frequency deviation change rate scan number, and the current frequency deviation scan number; If the spectrum peak value exceeds the peak value threshold, the capture result is determined to be a successful capture.

16. The method according to claim 15, characterized in that The step of determining a peak threshold based on the signal-to-noise ratio of the initial satellite signal comprises: Based on the signal-to-noise ratio of the initial satellite signal, a threshold determination formula is used to determine the peak threshold; the threshold determination formula is: th=T0·K·10 NF / 10 ·fsc·(Gn+snr·Gs) / 2 Where th is the peak threshold, T0 is the noise temperature, K is the Boltzmann constant, NF is the noise factor, fsc is the digital intermediate frequency sampling rate, Gn is the noise gain, and Gs is the signal gain.

17. The method according to claim 16, characterized in that The process of determining the noise gain includes: Using each of the multiple noise signals as an excitation source of a preset capture algorithm, determining a power ratio of each of the noise signals; the power ratio is a ratio between a maximum power of an output response signal corresponding to the noise signal and a power of the noise signal; An average value of power ratios of a plurality of the noise signals is determined as the noise gain.

18. The method according to claim 16, characterized in that The process of determining the signal gain includes: Using each of the plurality of training signals as an excitation source of a preset capture algorithm, determining a power ratio of each of the training signals; the power ratio is a ratio between a maximum power of an output response signal corresponding to the training signal and a power of the training signal; the training signal is a signal that conforms to a satellite signal system, contains a pseudo-random code consistent with a local signal, and has a signal-to-noise ratio greater than a preset signal-to-noise ratio threshold; An average value of power ratios of a plurality of the training signals is determined as the signal gain.

19. The method according to claim 15, characterized in that The determining of the capture result based on at least one of the current delay scan number, the current frequency deviation change rate scan number, and the current frequency deviation scan number includes: Determine whether the current delay scan number has reached an upper limit; If the current delay scan number does not reach the upper limit, a first loop operation is performed based on the remaining delay estimate values ​​in the delay set to be scanned, until it is determined that the capture result is successful capture or the current delay scan number reaches the upper limit; the first loop operation includes performing delay compensation on the second satellite signal based on the delay estimate value corresponding to the next delay scan number in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and fast Fourier transform-based peak generation processing on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result; If the current delay scan times have reached the upper limit, the capture result is determined to be a capture failure, or the capture result is determined based on at least one of the current frequency offset change rate scan times and the current frequency offset scan times.

20. The method according to claim 19, characterized in that The determining the capture result based on at least one of the current frequency offset change rate scanning number and the current frequency offset scanning number includes: Determine whether the current frequency deviation change rate scanning times has reached an upper limit value; If the current frequency offset change rate scanning times does not reach the upper limit, a second loop operation is performed based on the remaining Doppler frequency offset change rate estimated values ​​in the frequency offset change rate set to be scanned, until it is determined that the capture result is successful capture or the current frequency offset change rate scanning times reaches the upper limit; the second loop operation includes performing Doppler effect compensation and code Doppler effect compensation on the first satellite signal based on the Doppler frequency offset change rate estimated value corresponding to the next frequency offset change rate scanning times in the frequency offset change rate set to be scanned, so as to obtain a new second satellite signal, and performing a third loop operation based on the delay estimated value in the delay set to be scanned, until it is determined that the capture result is successful capture or the current delay scanning times has reached the upper limit; the third loop operation includes performing delay compensation on the new second satellite signal based on the delay estimated value in the delay set to be scanned, so as to obtain a new third satellite signal, and performing partial matched filtering and peak generation processing based on fast Fourier transform on the new third satellite signal, so as to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result; If the current frequency offset change rate scanning times has reached the upper limit, the capture result is determined to be a capture failure, or the capture result is determined based on the current frequency offset scanning times.

21. The method according to claim 20, characterized in that The determining of the capture result based on the current frequency offset scanning number includes: Determine whether the current frequency deviation scan times has reached an upper limit; If the current number of frequency offset scans has not reached the upper limit, a fourth loop operation is performed based on the remaining Doppler frequency offset estimates in the frequency offset set to be scanned until the capture result is determined to be successful or the current number of frequency offset scans reaches the upper limit; the fourth loop operation includes performing Doppler effect compensation on the first satellite signal based on the Doppler frequency offset estimate corresponding to the next frequency offset scan number in the frequency offset set to be scanned, and performing a fifth loop operation based on the Doppler frequency offset change rate estimate in the frequency offset change rate set to be scanned until the capture result is determined to be successful or the current number of frequency offset change rate scans reaches the upper limit; the fifth loop operation includes performing Doppler effect compensation on the first satellite signal based on the Doppler frequency offset estimate corresponding to the next frequency offset scan number in the frequency offset set to be scanned. The method further comprises: performing code Doppler effect compensation on the Doppler frequency offset change rate estimate in the change rate set to obtain a new second satellite signal, and performing a sixth loop operation based on the delay estimate in the delay set to be scanned, until it is determined that the capture result is successful capture or the current delay scan number has reached an upper limit; the sixth loop operation includes performing delay compensation on the new second satellite signal based on the delay estimate in the delay set to be scanned to obtain a new third satellite signal, performing partial matched filtering and fast Fourier transform-based peak generation processing on the new third satellite signal to obtain a new spectrum peak, and performing peak detection based on the new spectrum peak to obtain a capture result; If the current frequency offset scanning times has reached the upper limit, it is determined that the capture result is a capture failure.

22. The method according to claim 15, characterized in that The capture result also includes a reference compensation value; the reference compensation value is used for the historical capture result, and the reference compensation value includes a reference Doppler frequency deviation, a reference Doppler frequency deviation change rate, a reference Doppler code rate offset, a reference Doppler code rate offset change rate and a reference delay; After determining that the capture result is a capture success, the method further includes: Determine the current delay estimate as the reference delay; Determine the current Doppler frequency deviation change rate estimate as the reference Doppler frequency deviation change rate; Based on the reference Doppler frequency deviation change rate, a code rate offset change rate estimation formula is used to determine a reference Doppler code rate offset change rate; Determine the current Doppler frequency offset estimate as the first frequency offset component, and determine the second frequency offset component using a frequency offset component determination formula based on the frequency spectrum position corresponding to the frequency spectrum peak; Determine the sum of the first frequency offset component and the second frequency offset component as a reference Doppler frequency offset; Based on the reference Doppler frequency offset, a code rate offset estimation formula is used to determine a reference Doppler code rate offset.

23. A satellite signal acquisition device, characterized in that: include: A carrier stripping module, used for stripping the carrier of the received initial satellite signal to obtain a first satellite signal; A Doppler compensation module, configured to perform Doppler effect compensation and code Doppler effect compensation on the first satellite signal to obtain a second satellite signal; A delay compensation module, configured to perform delay compensation on the second satellite signal to obtain a third satellite signal; A correlation despreading module, configured to perform partial matched filtering and peak generation processing based on fast Fourier transform on the third satellite signal to obtain a spectrum peak; A peak detection module, used for performing peak detection based on the spectrum peak to obtain a capture result; The capture result indicates capture success or capture failure.

24. An electronic device, characterized in that: include: A processor and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the satellite signal acquisition method according to any one of claims 1 to 22.

25. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the satellite signal acquisition method according to any one of claims 1 to 22.

26. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the satellite signal acquisition method according to any one of claims 1 to 22 is implemented.

Images