A high-sensitivity signal tracking method and device using a multi-decision extrapolation strategy

Abstract

The present invention relates to a high-sensitivity signal tracking method using a multi-decision extrapolation strategy under dynamic compensation, comprising: performing segmented compensation on the correlation between a navigation signal with a Doppler change rate after down-conversion and a local signal; performing an FFT operation on each set of Doppler change rate compensation results; performing modulus calculation on multiple sets of FFT frequency domain data, selecting the maximum modulus and its corresponding frequency domain index; calculating a carrier deviation based on the frequency domain index corresponding to the maximum modulus; comparing the carrier deviation and the maximum modulus with their noise mean multiplied by a coefficient as a threshold; performing carrier step updates and recording the number of updates and carrier Doppler, or enabling a least squares extrapolation algorithm to update carrier parameters, or determining loop lock loss and performing signal recapture. The technical solution of the present invention can reduce compensation accuracy and computational complexity under strong signal conditions, and improve accuracy and enhance signal coherence gain under weak signal conditions.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation signal tracking technology, and in particular to a high-sensitivity signal tracking method, system, and readable storage medium and computer equipment of a multi-decision extrapolation strategy under dynamic compensation. Background Art

[0002] With the advent of the commercial space era, the number of deep-space vehicles and their missions is increasing. Deep-space missions are characterized by long, dynamic, and far-flung targets. Currently, these missions still rely on deep-space tracking and control systems, requiring a loopback control system from the tracking and control station to the spacecraft. This presents challenges such as command latency, tracking and control accuracy, and data transmission rates, impacting their real-time performance, effectiveness, safety, and reliability. Autonomous navigation technology for vehicles is an effective solution to these challenges and has become a key development direction for future deep-space exploration technology, with GNSS as a key tool.

[0003] The main lobe beam of a GNSS navigation satellite antenna primarily covers the Earth. The main lobe beam of a navigation satellite transmitting antenna has a range of approximately 23.5°, with most signals completely blocked by the Earth. Sidelobe signal power is approximately 15dB-20dB lower than the mainlobe signal power. Spacecraft need to receive sidelobe signals to increase the number of available navigation satellites. Deep space spacecraft are located at great distances from navigation satellites, resulting in high free-space path loss and even weaker sidelobe signal power received by the receiver.

[0004] The spacecraft flies at a high speed, and the Doppler shift and Doppler shift change rate generated by its relative motion with the navigation satellite are relatively large. When the dynamics are unknown or cannot be accurately predicted, the receiver needs to have strong dynamic signal reception capabilities.

[0005] Problems with existing technologies: (1) Research has mostly focused on the anti-interference of single-constellation or dual-constellation deep combination structures and performance analysis in weak signal and high dynamic environments. In addition, most of the satellites in their simulation environments have good visibility, and the tracking sensitivity of deep space GNSS has not yet reached the expected indicators. (2) When the GNSS signal is continuously in an extremely weak state, the GNSS / INS deep combination still mainly relies on the performance of the INS. The stability of existing methods is not sufficient and is not sustainable. Loss of lock will still occur during long-term tracking. Therefore, improving the sustainability and stability of GNSS tracking methods is also a problem that needs to be solved. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0007] To this end, an object of the present invention is to provide a high-sensitivity signal tracking method and device with a multi-decision extrapolation strategy under dynamic compensation, which can reduce the compensation accuracy and reduce the amount of calculation under strong signal conditions, and improve the accuracy and enhance its signal coherence gain under weak signal conditions.

[0008] To achieve the above objectives, the technical solution of the first aspect of the present invention provides a high-sensitivity signal tracking method using a multi-decision extrapolation strategy under dynamic compensation, comprising:

[0009] Performing segmented compensation on the correlation results between the down-converted navigation signal with Doppler variation rate and the local signal to obtain multiple sets of Doppler variation rate compensation results;

[0010] Perform FFT operation on each set of Doppler change rate compensation results to obtain multiple sets of FFT frequency domain data;

[0011] Calculate the modulus of multiple sets of FFT frequency domain data and select the maximum modulus and its corresponding frequency domain index;

[0012] Calculating a carrier deviation based on a frequency domain index corresponding to a maximum modulus value;

[0013] The carrier deviation and the maximum modulus are compared with the noise mean multiplied by a coefficient as a threshold;

[0014] If the carrier deviation is within the preset reasonable value and the maximum modulus exceeds the threshold, the frequency domain peak is judged to be valid, the carrier step is updated, and the update number and carrier Doppler are recorded;

[0015] If the carrier deviation exceeds the preset reasonable value and the maximum modulus value does not exceed the threshold for several consecutive times, the number of times it is not updated is added;

[0016] If the number of unupdated times is greater than or equal to a first threshold, enabling a least squares extrapolation algorithm to update the carrier parameters;

[0017] If the number of times the signal is not updated is greater than or equal to the second threshold, the loop is determined to be unlocked and signal recapture is performed;

[0018] The second threshold is greater than the first threshold.

[0019] In the above technical solution, preferably, segmented compensation is performed on the correlation result between the down-converted navigation signal with the Doppler change rate and the local signal, which specifically includes the following steps:

[0020] Receive navigation signals with Doppler change rate transmitted from navigation satellites and perform down-conversion processing on the navigation signals;

[0021] Pre-configure a local recurring signal and pre-compensate the local recurring signal for Doppler variation rate;

[0022] The navigation signal with Doppler variation rate after down-conversion is correlated with the local signal to obtain the coherent integration result;

[0023] Performing segmented compensation of multiple groups of Doppler change rates on the coherent integration results to obtain multiple groups of Doppler change rate compensation results.

[0024] In the above technical solution, preferably, the navigation signal transmitted by the navigation satellite is expressed as:

[0025]

[0026] Where A is the signal amplitude, C(k) is the C / A code sequence value at time k, D(k) is the navigation message at time k, and f IF Indicates the intermediate frequency carrier frequency, f d represents the Doppler frequency deviation, represents the Doppler change rate, T is the sampling period, represents the initial phase of the carrier. n(k) is the center frequency at f IF Gaussian white noise.

[0027] In the above technical solution, preferably, correlation processing is performed on the navigation signal with the Doppler change rate after down-conversion and the local signal, specifically including:

[0028] The intermediate frequency signal in the navigation signal is transformed into zero intermediate frequency, and the Doppler change rate pre-compensation is performed on it and then coherent accumulation is performed to obtain:

[0029]

[0030] Among them, C L (k) is the local code, f L is the local reproduced carrier frequency, is the local Doppler change rate pre-compensation, L is the number of sampling points, is the initial phase of the local reproduced carrier, Δf=f IF +f d -f L and is the Doppler frequency offset and phase residual, is the residual Doppler change rate;

[0031] Autocorrelation function in the case of code alignment If the navigation message is stripped, D(k) = 1, and the coherent accumulation can be simplified to the following formula:

[0032] The local reproduced signal is coherently accumulated for m seconds and n segments are accumulated. By configuring different m and n, the coherent integration time and the number of integration segments can be changed.

[0033] In the above technical solution, preferably, performing segmented compensation of multiple groups of Doppler change rates on the coherent integration results specifically includes:

[0034] Doppler rate compensation coefficient for: Where ξ is the Doppler rate compensation coefficient index, Indicates the Doppler change rate search range, To compensate for accuracy;

[0035] i is the number of coherent accumulation segments, φ(i, ξ) is the Doppler change rate compensation value The phase modulation value of the coherent accumulation of the i-th segment at time ;

[0036] g(i, ξ) = s(i)·φ(ξ), i = 0, 1, ..., n-1; g(i, ξ) is the Doppler change rate compensation value of the i-th segment The coherent accumulation value of .

[0037] In the above technical solution, preferably, performing an FFT operation on each set of Doppler change rate compensation results specifically includes:

[0038] G(ω,ξ) represents the result of n-point FFT of g(i,ξ);

[0039] For different Doppler compensation value index ξ, we can get Group FFT results and record the following array Y(ω,ξ);

[0040]

[0041] [p max ,q max ]=arg max|Y(ω,ξ)|, where |Y(ω,ξ)| represents the modulus of the values ​​in the array Y(ω,ξ), p max is the maximum value in the array after Y(ω,ξ) is modulo, q max The index corresponding to the maximum value in the array after taking the modulus of Y(ω,ξ).

[0042] In the above technical solution, preferably, the expression of the threshold is: thrdsh = N × μ (G (ω, ξ)), N∈R + , μ(G(ω,ξ)) is the mean of the G(ω,ξ) array, that is, μ(G(ω,ξ)) is the mean of the noise G(x), N is the noise coefficient, R + is represented as a set of positive real numbers;

[0043] Update the carrier step including: when the spectrum line index q max ≤H and pmax >thresh, When q max >nH and p max >thresh,

[0044]

[0045] Among them, m is the coherent accumulation time in seconds, n is the number of coherent accumulation segments, f s is the sampling rate, H is a preset reasonable value;

[0046] Record the update times and updated carrier Doppler values ​​and record them in the corresponding matrix In the , the first column is the update number, the second column is the carrier Doppler value, and λ is the number of updates before extrapolation. The carrier Doppler calculation method is as follows:

[0047] Enable the least squares extrapolation algorithm to update carrier parameters, including:

[0048] Introducing the mean and Obtain carrier parameters The carrier parameters a and b are the slope and intercept of the linear equation, so the estimated carrier Doppler frequency is:

[0049] Carrier_dop=a·(x λ +i)+b, where i is the number of times the link is not updated. When the number of times the link is not updated i is greater than or equal to the second threshold, it indicates that the loop is locked.

[0050] The technical solution of the second aspect of the present invention provides a high-sensitivity signal tracking system with a multi-decision extrapolation strategy under dynamic compensation, comprising:

[0051] The compensation module is configured to perform segmented compensation on the correlation between the down-converted navigation signal with the Doppler change rate and the local signal to obtain multiple sets of Doppler change rate compensation results;

[0052] The FFT operation module is configured to perform an FFT operation on each set of Doppler change rate compensation results to obtain multiple sets of FFT frequency domain data;

[0053] A modulus calculation module is configured to perform modulus calculation on multiple sets of FFT frequency domain data and select the maximum modulus value and its corresponding frequency domain index;

[0054] a carrier deviation calculation module configured to calculate the carrier deviation according to a frequency domain index corresponding to the maximum modulus value;

[0055] A comparison module is configured to perform comparison based on a carrier deviation and a maximum modulus value and a noise mean value multiplied by a coefficient as a threshold;

[0056] The carrier step update module is configured to determine that the frequency domain peak is valid, update the carrier step, and record the number of updates and the carrier Doppler if the carrier deviation is within a preset reasonable value and the maximum modulus exceeds a threshold; and if the carrier deviation exceeds the preset reasonable value and the maximum modulus does not exceed the threshold for several consecutive times, add the number of unupdated times;

[0057] a carrier parameter updating module configured to enable a least squares extrapolation algorithm to update the carrier parameters if the number of unupdated times is greater than or equal to a first threshold;

[0058] a signal recapture module configured to determine that the loop is unlocked and perform signal recapture if the number of unupdated times is greater than or equal to a second threshold;

[0059] The second threshold is greater than the first threshold.

[0060] The technical solution of the third aspect of the present invention provides a readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation provided by the technical solution of the first aspect are implemented.

[0061] The technical solution of the fourth aspect of the present invention provides a computer device, including a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to implement the steps of the high-sensitivity signal tracking method of the multi-decision extrapolation strategy under dynamic compensation provided by the technical solution of the first aspect above.

[0062] Compared with the prior art, the advantages of the high-sensitivity signal tracking method and device with a multi-decision extrapolation strategy under dynamic compensation provided by the present invention are:

[0063] 1. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation provided by the present invention compensates for the Doppler change rate of the received signal and the local correlation result in segments, and can flexibly adjust the compensation accuracy, so that the compensation accuracy is reduced to reduce the amount of calculation under strong signal conditions, and the accuracy is improved to enhance its signal coherence gain under weak signal conditions.

[0064] 2. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation provided by the present invention proposes a threshold selection scheme. The threshold value is selected as the noise average multiplied by the coefficient N, which can effectively improve the stability of satellite navigation signal tracking.

[0065] 3. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation provided by the present invention proposes multiple decision and extrapolation schemes, which can improve the continuity of satellite navigation signal tracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0067] Figure 1 This is a principle block diagram of a high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation;

[0068] Figure 2 A flowchart of a high-sensitivity signal tracking method according to an embodiment of the present invention is shown;

[0069] Figure 3 shows a flowchart of step S1 involved in an embodiment of the present invention;

[0070] Figure 4 This is a schematic diagram of the energy of the three branches of the EPL tracking channel;

[0071] Figure 5 Schematic diagram for estimating the carrier-to-noise ratio of the received signal;

[0072] Figure 6 Schematic diagram of the change of the carrier frequency of the transmitted signal;

[0073] Figure 7 This is a schematic diagram of the local carrier frequency update result of this method;

[0074] Figure 8 The figure shows a structural block diagram of a high-sensitivity signal tracking system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0075] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0076] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0077] like Figures 1 to 6 As shown, according to an embodiment of the present invention, a high-sensitivity signal tracking method using a multi-decision extrapolation strategy under dynamic compensation includes:

[0078] S1, performing segmented compensation on the correlation results of the down-converted navigation signal with Doppler variation rate and the local signal to obtain multiple sets of Doppler variation rate compensation results;

[0079] S2, performing FFT operation on each set of Doppler change rate compensation results to obtain multiple sets of FFT frequency domain data;

[0080] S3, performing modulus calculation on multiple sets of FFT frequency domain data, and selecting the maximum modulus and its corresponding frequency domain index;

[0081] S4, calculating the carrier deviation according to the frequency domain index corresponding to the maximum modulus value;

[0082] S5, compare the carrier deviation and the maximum modulus with the noise mean multiplied by a coefficient as a threshold;

[0083] S6, if the carrier deviation is within the preset reasonable value and the maximum modulus exceeds the threshold, the frequency domain peak is determined to be valid, the carrier step is updated, and the update number and carrier Doppler are recorded;

[0084] S7, if the carrier deviation exceeds the preset reasonable value and the maximum modulus value does not exceed the threshold for several consecutive times, the number of unupdated times is added;

[0085] S8, if the number of unupdated times is greater than or equal to the first threshold, enabling the least squares extrapolation algorithm to update the carrier parameters;

[0086] S9, if the number of unupdated times is greater than or equal to the second threshold, determining that the loop is unlocked and performing signal recapture;

[0087] The second threshold is greater than the first threshold, and both the first threshold and the second threshold are user-definable values.

[0088] In the above embodiment, preferably, S1, performing segmented compensation on the correlation result between the down-converted navigation signal with the Doppler variation rate and the local signal, specifically comprises the following steps:

[0089] S11, receiving a navigation signal with a Doppler variation rate transmitted from a navigation satellite and performing down-conversion processing on the navigation signal;

[0090] S12, pre-configuring a local recurring signal and performing Doppler change rate pre-compensation on the local recurring signal;

[0091] S13, performing correlation processing on the navigation signal with the Doppler change rate after down-conversion and the local signal to obtain a coherent integration result;

[0092] S14, performing segmented compensation of multiple groups of Doppler change rates on the coherent integration results to obtain multiple groups of Doppler change rate compensation results.

[0093] In the above embodiment, preferably, the navigation signal transmitted by the navigation satellite is expressed as:

[0094]

[0095] Where A is the signal amplitude, C(k) is the C / A code sequence value at time k, D(k) is the navigation message at time k, and f IF Indicates the intermediate frequency carrier frequency, f d represents the Doppler frequency deviation, represents the Doppler change rate, T is the sampling period, represents the initial phase of the carrier. n(k) is the center frequency at f IF Gaussian white noise.

[0096] In the above embodiment, preferably, correlation processing is performed on the navigation signal with the Doppler change rate after down-conversion and the local signal, specifically including:

[0097] The intermediate frequency signal in the navigation signal is transformed into zero intermediate frequency, and the Doppler change rate pre-compensation is performed on it and then coherent accumulation is performed to obtain:

[0098]

[0099] Among them, C L (k) is the local code, f L is the local reproduced carrier frequency, is the local Doppler change rate pre-compensation, L is the number of sampling points, is the initial phase of the local reproduced carrier, Δf=f IF +f d -f L and is the Doppler frequency offset and phase residual, is the residual Doppler change rate;

[0100] Autocorrelation function in the case of code alignment If the navigation message is stripped, D(k) = 1, and the coherent accumulation can be simplified to the following formula:

[0101] The local reproduced signal is coherently accumulated for m seconds and n segments are accumulated. By configuring different m and n, the coherent integration time and the number of integration segments can be changed.

[0102] In the above embodiment, preferably, performing segmented compensation of multiple groups of Doppler change rates on the coherent integration results specifically includes:

[0103] Doppler rate compensation coefficient for: Where ξ is the Doppler rate compensation coefficient index, Indicates the Doppler change rate search range, which can be customized according to the satellite dynamic situation. For compensation accuracy, the compensation accuracy can also be flexibly configured. The higher the compensation accuracy, the better the compensation effect. The lower the compensation accuracy, the lower the algorithm complexity. It can be customized according to the signal strength.

[0104] i is the number of coherent accumulation segments, φ(i, ξ) is the Doppler change rate compensation value The phase modulation value of the coherent accumulation of the i-th segment at time ;

[0105] g(i, ξ) = s(i)·φ(ξ), i = 0, 1, ..., n-1; g(i, ξ) is the Doppler change rate compensation value of the i-th segment The coherent accumulation value of .

[0106] In the above embodiment, preferably, an FFT operation is performed on each set of Doppler change rate compensation results, specifically including:

[0107] G(ω,ξ) represents the result of n-point FFT of g(i,ξ);

[0108] For different Doppler compensation value index ξ, we can get Group FFT results and record the following array Y(ω,ξ);

[0109]

[0110] [p max ,q max ]=arg max|Y(ω,ξ)|, where |Y(ω,ξ)| represents the modulus of the values ​​in the array Y(ω,ξ), p max is the maximum value in the array after Y(ω,ξ) is modulo, q max The index corresponding to the maximum value in the array after taking the modulus of Y(ω,ξ).

[0111] In the above embodiment, preferably, the expression of the threshold is: thresh = N × μ (G (ω, ξ)), N∈R + , μ(G(ω,ξ)) is the mean of the G(ω,ξ) array, that is, μ(G(ω,ξ)) is the mean of the noise G(x), N is the noise coefficient, and the noise coefficient N can be selected according to the actual situation, R + is represented as a set of positive real numbers;

[0112] Update the carrier step including: when the spectrum line index q max ≤H and p max >thresh, When q max >nH and p max >thresh,

[0113]

[0114] Among them, m is the coherent accumulation time in seconds, n is the number of coherent accumulation segments, f s is the sampling rate, H is a preset reasonable value, and the preset reasonable value H can be customized according to actual conditions;

[0115] Record the update times and updated carrier Doppler values ​​and record them in the corresponding matrix In , the first column is the update number, the second column is the carrier Doppler value, and λ is the number of updates before extrapolation. The carrier Doppler calculation method is as follows:

[0116] Enable the least squares extrapolation algorithm to update carrier parameters, including:

[0117] Introducing the mean and Obtain carrier parameters The carrier parameters a and b are the slope and intercept of the linear equation, so the estimated carrier Doppler frequency is:

[0118] Carrier_dop=a·(x λ +i)+b, where i is the number of unupdated times. When the number of unupdated times i is greater than or equal to the second threshold, it indicates that the loop is locked. If the number of unupdated times is greater than or equal to the first threshold, the previously recorded number of updates and carrier Doppler results are used for extrapolation.

[0119] like Figure 1 The figure shows a high-sensitivity signal tracking method using a multi-decision extrapolation strategy with dynamic compensation. This approach extends the coherent integration time by stripping the navigation message and provides a segmented Doppler rate compensation method. By selecting the compensation accuracy, segment duration, and number of segments, tracking sensitivity and accuracy are improved, while computational effort is reduced and acquisition efficiency is enhanced. Threshold selection, multiple decisions, and extrapolation methods are used to enhance the stability and continuity of satellite navigation signal tracking.

[0120] Figure 1 In the symbol FFT result, it means: under the preset compensation accuracy condition, for each Doppler compensation point, the result value array obtained after the FFT operation.

[0121] Figure 1 In the figure, the symbol MAX means the maximum value of the modulus value in the array after the FFT operation at each Doppler compensation point under the preset compensation accuracy conditions. This maximum value and the maximum FFT spectrum line index are recorded for subsequent carrier NCO updates.

[0122] Example 1:

[0123] Taking the GPS L1C / A signal as an example, the transmit signal configuration is as follows: the carrier-to-noise ratio (CN0) is 50 dBHz from 0 to 3 seconds, decreases to 30 dBHz from 3 to 6 seconds, drops to 10 dBHz from 6 to 30 seconds, and returns to 50 dBHz from 30 to 42 seconds. The Doppler is 20 Hz, with a Doppler variation rate of -2.6257 Hz / s.

[0124] When the signal strength is greater than or equal to 50dBHz, the phase-locked loop is used to update the local carrier. When the signal strength is less than 50dBHz, this solution is used to update the local carrier.

[0125] The local reception configuration is: coherent accumulation time m = 0.003, coherent accumulation segment number and FFT point number n = 1000, local Doppler change rate pre-compensation Doppler change rate search range f′ rate =3, Doppler change rate compensation accuracy f x ′=0.0001, number of times not updated α=2, number of times not updated β=5, threshold coefficient N=3.

[0126] Figure 4 This is the energy result diagram of the three branches of tracking advance, alignment and lag, namely EPL, under the conditions of this example. It can be seen that the energy is highest when aligned.

[0127] Figure 5 The following is a diagram of the carrier-to-noise ratio estimation under the conditions of this example. It shows that during the initial 0-3 seconds, the signal strength is high at 50dBHz, enabling good tracking using the phase-locked loop. From 3-6 seconds, the carrier-to-noise ratio drops to 30dBHz, and the carrier-to-noise ratio estimate is also at 30dBHz. From 6-30 seconds, the carrier-to-noise ratio drops to 10dBHz, making carrier-to-noise estimation impossible due to the extremely weak signal strength. However, after the carrier-to-noise ratio returns to a high 50dBHz from 30-42 seconds, the carrier-to-noise ratio estimate also rises to 50dBHz. Therefore, good tracking is maintained during the 3-30 seconds period of extremely weak signals.

[0128] Depend on Figure 6 and Figure 7 It can be seen that the local carrier is continuously updated and maintains the same slope and rate of change as the local transmit signal carrier-to-noise ratio.

[0129] The tracking sensitivity of the algorithm for GPS L1C / A under different parameters is shown in Table 1.

[0130] Table 1 Tracking sensitivity of the algorithm for GPS L1C / A under different parameters

[0131] Doppler rate of change FFT points Duration per point CN0 Tracking sensitivity 1000 points per second -5.2514Hz / s 1000 1ms 14dBHz -160dBm 2s1000 points -5.2514Hz / s 1000 2ms 12dBHz -162dBm 3s1000 points -5.2514Hz / s 1000 3ms 10dBHz -164dBm 3s1000 points -1.3129Hz / s 1000 3ms 8dBHz -166dBm 5s1000 points -1.3129Hz / s 1000 5ms 7dBHz -167dBm

[0132] In summary, the example of the present application provides a high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation. The scheme includes the following steps: generating a local intermediate frequency carrier, configuring a local reproduced signal, correlating the navigation signal after down-conversion with the local reproduced signal, obtaining a coherent integration result and storing it in an array, then performing carrier Doppler change rate compensation on the coherent integration result, performing FFT operation on the compensated result, performing modulo and selecting the maximum value on multiple groups of results of the FFT operation to obtain their energy value and index. Whether to update is determined by threshold selection and carrier deviation. If the number of updates does not reach the preset value, the extrapolation method is updated. This method improves tracking sensitivity and achieves continuous and stable tracking of highly dynamic weak signals.

[0133] like Figure 8 As shown, a high-sensitivity signal tracking system 1000 with a multi-decision extrapolation strategy under dynamic compensation according to another embodiment of the present invention includes:

[0134] The compensation module 10 is configured to perform segmented compensation on the correlation between the down-converted navigation signal with the Doppler variation rate and the local signal to obtain multiple sets of Doppler variation rate compensation results;

[0135] The FFT operation module 20 is configured to perform an FFT operation on each set of Doppler change rate compensation results to obtain multiple sets of FFT frequency domain data;

[0136] The modulus calculation module 30 is configured to perform modulus calculation on multiple sets of FFT frequency domain data, select the maximum modulus and its corresponding frequency domain index

[0137] a carrier deviation calculation module 40 configured to calculate the carrier deviation according to the frequency domain index corresponding to the maximum modulus value;

[0138] The comparison module 50 is configured to compare the carrier deviation and the maximum modulus with the noise mean multiplied by a coefficient as a threshold;

[0139] The carrier step update module 60 is configured to determine that the frequency domain peak is valid, update the carrier step, and record the number of updates and the carrier Doppler if the carrier deviation is within a preset reasonable value and the maximum modulus exceeds a threshold; and to add the number of unupdated times if the carrier deviation exceeds the preset reasonable value and the maximum modulus does not exceed the threshold for several consecutive times;

[0140] The carrier parameter updating module 70 is configured to enable a least squares extrapolation algorithm to update the carrier parameters if the number of unupdated times is greater than or equal to a first threshold;

[0141] The signal recapture module 80 is configured to determine that the loop is unlocked and perform signal recapture if the number of unupdated times is greater than or equal to a second threshold;

[0142] The second threshold is greater than the first threshold.

[0143] Based on the above Figures 1 to 7 The method shown, accordingly, an embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored, which, when executed by a processor, implements the steps of the high-sensitivity signal tracking method of the multi-decision extrapolation strategy under dynamic compensation of any of the above embodiments.

[0144] Based on this understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, USB flash drive, mobile hard disk, etc.), and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods of various implementation scenarios of the present application.

[0145] Based on the above Figures 1 to 7 The method shown, and Figure 8 The virtual device embodiment shown, in order to achieve the above-mentioned purpose, the embodiment of the present application also provides a computer device, including a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to implement the steps of the high-sensitivity signal tracking method of the multi-decision extrapolation strategy under dynamic compensation of any of the above embodiments.

[0146] Optionally, the computer device may further include a user interface, a network interface, a camera, a radio frequency (RF) circuit, a sensor, an audio circuit, a Wi-Fi module, etc. The user interface may include a display, an input unit such as a keyboard, etc., and the optional user interface may also include a USB interface, a card reader interface, etc. The network interface may optionally include a standard wired interface, a wireless interface (such as a Bluetooth interface, a Wi-Fi interface), etc.

[0147] Those skilled in the art will understand that the computer device structure provided in this embodiment does not constitute a limitation on the computer device, and may include more or fewer components, or a combination of certain components, or different component arrangements.

[0148] The storage medium may also include an operating system and a network communication module. An operating system is a program that manages and stores the hardware and software resources of a computer device, supporting the execution of information processing programs and other software and / or programs. The network communication module facilitates communication between components within the storage medium, as well as with other hardware and software within the physical device.

[0149] In the present invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless expressly limited otherwise. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; "connected" can mean a direct connection or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0150] In the description of the present invention, it should be understood that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0151] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0152] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation, characterized in that: include: Performing segmented compensation on the correlation results between the down-converted navigation signal with Doppler variation rate and the local signal to obtain multiple sets of Doppler variation rate compensation results; Performing an FFT operation on each set of Doppler change rate compensation results to obtain multiple sets of FFT frequency domain data; Performing modulus calculation on multiple sets of FFT frequency domain data, and selecting the maximum modulus and its corresponding frequency domain index; Calculating a carrier deviation according to a frequency domain index corresponding to the maximum modulus value; Comparing the carrier deviation and the maximum modulus with the noise mean multiplied by a coefficient as a threshold; If the carrier deviation is within a preset reasonable value and the maximum modulus exceeds the threshold, the frequency domain peak is determined to be valid, the carrier step is updated, and the update number and carrier Doppler are recorded; If the carrier deviation exceeds a preset reasonable value and the maximum modulus value does not exceed the threshold for several consecutive times, the number of unupdated times is added; If the number of unupdated times is greater than or equal to a first threshold, enabling a least squares extrapolation algorithm to update the carrier parameters; If the number of times the signal is not updated is greater than or equal to the second threshold, the loop is determined to be unlocked and signal recapture is performed; The second threshold is greater than the first threshold.

2. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to claim 1, characterized in that: The result of correlating the down-converted navigation signal with the Doppler variation rate with the local signal is compensated in sections, specifically including the following steps: receiving a navigation signal with a Doppler variation rate transmitted from a navigation satellite and performing down-conversion processing on the navigation signal; Pre-configure a local recurring signal and pre-compensate the local recurring signal for Doppler variation rate; The navigation signal with Doppler variation rate after down-conversion is correlated with the local signal to obtain the coherent integration result; Performing segmented compensation of multiple groups of Doppler change rates on the coherent integration results to obtain multiple groups of Doppler change rate compensation results.

3. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to claim 2, characterized in that: The expression of the navigation signal transmitted by the navigation satellite is: Where A is the signal amplitude, C(k) is the C / A code sequence value at time k, D(k) is the navigation message at time k, and f IF Indicates the intermediate frequency carrier frequency, f d represents the Doppler frequency deviation, represents the Doppler change rate, T is the sampling period, represents the initial phase of the carrier; n(k) is the center frequency at f IF Gaussian white noise.

4. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to claim 3, characterized in that: The down-converted navigation signal with Doppler variation rate is correlated with the local signal, specifically including: The intermediate frequency signal in the navigation signal is transformed into zero intermediate frequency, and the Doppler change rate pre-compensation is performed on it and then coherent accumulation is performed to obtain: Among them, C L (k) is the local code, f L is the local reproduced carrier frequency, is the local Doppler change rate pre-compensation, L is the number of sampling points, is the initial phase of the local reproduced carrier, Δf=f IF +f d -f L and is the Doppler frequency offset and phase residual, is the residual Doppler change rate; Autocorrelation function in the case of code alignment If the navigation message is stripped, D(k) = 1, and the coherent accumulation can be simplified to the following formula: The local reproduced signal is coherently accumulated for m seconds and n segments are accumulated. By configuring different m and n, the coherent integration time and the number of integration segments can be changed.

5. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to claim 4, characterized in that: Performing segmented compensation of multiple groups of Doppler change rates on the coherent integration results, specifically comprising: Doppler rate compensation coefficient for: Where ξ is the Doppler rate compensation coefficient index, Indicates the Doppler change rate search range, To compensate for accuracy; i is the number of coherent accumulation segments, φ(i, ξ) is the Doppler change rate compensation value The phase modulation value of the coherent accumulation of the i-th segment at time ; g(i, ξ) = s(i)·φ(ξ), i = 0, 1, ..., n-1; g(i, ξ) is the Doppler change rate compensation value of the i-th segment The coherent accumulation value of .

6. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to claim 5, characterized in that: Performing an FFT operation on each set of Doppler rate of change compensation results, specifically including: G(ω,ξ) represents the result of n-point FFT of g(i,ξ); For different Doppler compensation value index ξ, we can get Group FFT results and record the following array Y(ω,ξ); [p max ,q max ]=arg max|Y(ω,ξ)|, where |Y(ω,ξ)| represents the modulus of the values ​​in the array Y(ω,ξ), p max is the maximum value in the array after Y(ω,ξ) is modulo, q max The index corresponding to the maximum value in the array after taking the modulus of Y(ω,ξ).

7. The high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to claim 6, characterized in that: The threshold expression is: thrdsh = N × μ (G (ω, ξ)), N ∈ R + , μ(G(ω,ξ)) is the mean of the G(ω,ξ) array, that is, μ(G(ω,ξ)) is the mean of the noise G(x), N is the noise coefficient, R + is the set of positive real numbers; The updating of the carrier step comprises: when the spectral line index q max ≤H and p max > thresh, When q max >nH and p max > thresh, Among them, m is the coherent accumulation time in seconds, n is the number of coherent accumulation segments, f s is the sampling rate, H is a preset reasonable value; Record the update times and updated carrier Doppler values ​​and record them in the corresponding matrix In , the first column is the update number, the second column is the carrier Doppler value, and λ is the number of updates before extrapolation. The carrier Doppler calculation method is as follows: Enable the least squares extrapolation algorithm to update carrier parameters, including: Introducing the mean and Obtain carrier parameters The carrier parameters a and b are the slope and intercept of the linear equation, so the estimated carrier Doppler frequency is: Carrier_dop=a·(x λ +i)+b, where i is the number of times the link is not updated. When the number of times the link is not updated is greater than or equal to the second threshold, it indicates that the loop is locked.

8. A high-sensitivity signal tracking system with a multi-decision extrapolation strategy under dynamic compensation, characterized in that: include: The compensation module is configured to perform segmented compensation on the correlation between the down-converted navigation signal with the Doppler change rate and the local signal to obtain multiple sets of Doppler change rate compensation results; An FFT operation module is configured to perform an FFT operation on each set of Doppler change rate compensation results to obtain multiple sets of FFT frequency domain data; a modulus calculation module configured to perform modulus calculation on multiple sets of FFT frequency domain data and select a maximum modulus value and its corresponding frequency domain index; a carrier deviation calculation module, configured to calculate the carrier deviation according to the frequency domain index corresponding to the maximum modulus value; a comparison module configured to perform comparison based on the carrier deviation and the maximum modulus and the noise mean multiplied by a coefficient as a threshold; The carrier step update module is configured to determine that the frequency domain peak is valid, update the carrier step, and record the number of updates and the carrier Doppler if the carrier deviation is within a preset reasonable value and the maximum modulus exceeds a threshold; and if the carrier deviation exceeds the preset reasonable value and the maximum modulus does not exceed the threshold for several consecutive times, add the number of unupdated times; a carrier parameter updating module configured to enable a least squares extrapolation algorithm to update the carrier parameters if the number of unupdated times is greater than or equal to a first threshold; a signal recapture module configured to determine that the loop is unlocked and perform signal recapture if the number of unupdated times is greater than or equal to a second threshold; The second threshold is greater than the first threshold.

9. A readable storage medium, characterized in that: A computer program is stored thereon, which, when executed by a processor, implements the steps of the high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to any one of claims 1 to 7.

10. A computer device, characterized in that: The invention comprises a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to implement the steps of the high-sensitivity signal tracking method with a multi-decision extrapolation strategy under dynamic compensation according to any one of claims 1 to 7.

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