Multipath signal identification method and related device

Abstract

This application discloses a multipath signal identification method and related apparatus, wherein the method comprises: selecting a target interval from N multipath delay intervals in a preset order, wherein the multipath delay ranges of the N multipath delay intervals do not overlap, and N is an integer greater than or equal to 2; performing multipath signal identification on each target interval when the target interval is selected to obtain an identification result; and if the identification result indicates that the target interval does not include a multipath signal, continuously selecting the next target interval from the N multipath delay intervals until the selected target interval includes a multipath signal, completing a single multipath signal identification process. This application can improve the problem of existing multipath signal identification methods that, while improving accuracy, consume a large amount of additional correlator resources.

Description

Technical Field

[0001] The present invention belongs to the field of satellite positioning technology, and in particular relates to a multipath signal recognition method, system, equipment and computer storage medium. Background Art

[0002] The Global Navigation Satellite System (GNSS) is a satellite-based radio navigation and positioning system that includes satellite navigation receivers. The receivers receive radio navigation signals and use them to perform navigation and positioning.

[0003] When satellite navigation receivers receive radio navigation signals, multipath effects can cause signal distortion. Therefore, it is necessary to estimate the components of the multipath signals to correct the pseudoranges in the original observations. Multipath signal component estimation, in turn, involves multipath signal identification. Related technologies for multipath signal identification require the use of a significant amount of additional correlator resources to improve the accuracy of the estimated multipath parameters. Summary of the Invention

[0004] The embodiments of the present invention provide a multipath signal identification method and related apparatus, which can improve the problem of the multipath signal identification method in the prior art that the accuracy is improved while the additional correlator resources are consumed more.

[0005] In a first aspect, a multipath signal identification method is provided, comprising:

[0006] Selecting a target interval from N multipath delay intervals in a preset order, wherein the multipath delay ranges of the N multipath delay intervals do not overlap, and N is an integer greater than or equal to 2;

[0007] Every time a target interval is selected, multipath signal recognition is performed on the target interval to obtain a recognition result;

[0008] When the identification result indicates that the target interval does not include the multipath signal, the next target interval is selected from the N multipath delay intervals until the selected target interval includes the multipath signal, thereby completing the single multipath signal identification process.

[0009] The embodiment of the present application divides the multipath delay interval into N intervals with different signal delays, and then sequentially performs multipath signal identification in the N intervals in a time-sharing manner. As a result, multipath signal identification can be completed using a small amount of correlator resources. Compared with related technologies, the number of additional correlators is reduced, thereby alleviating the problem of the existing multipath signal identification method consuming a large amount of additional correlator resources while improving accuracy.

[0010] Optionally, performing multipath signal identification on the target interval to obtain an identification result includes:

[0011] Starting a counter and repeatedly performing the multipath signal identification operation in a target interval;

[0012] Each time a recognition operation is completed, the corresponding operation result is obtained;

[0013] If the operation result indicates that a multipath signal is identified, the identification operation in the target interval is stopped, and multipath verification is performed on the target interval;

[0014] When the multipath verification of the target interval passes, the identification result indicates that the target interval includes a multipath signal;

[0015] If the operation result indicates that the multipath signal is not identified, the counter is incremented by one, and the identification operation is repeatedly performed in the target interval until the cumulative count of the counter reaches the number threshold. Then, it is determined whether the number of all the accumulated operation results indicating that the multipath signal is not identified exceeds the number threshold, and the number threshold is less than or equal to the number threshold.

[0016] If so, the identification result indicates that the target interval does not include multipath signals.

[0017] In this example, by repeatedly performing the multipath signal identification operation multiple times, and then based on the results of multiple times of not identifying the multipath signal, combining the multipath signal verification operation after identifying the multipath signal, the accuracy of multipath identification in a single target interval can be improved, and flexible switching of the target interval can be achieved.

[0018] Optionally, performing an identification operation on a multipath signal includes:

[0019] Receive navigation signals and convert them into digital intermediate frequency signals;

[0020] Signal processing is performed on the digital intermediate frequency signal through multiple correlators to obtain signal accumulation values ​​corresponding to the multiple correlators, and the identification intervals of the multiple correlators correspond to the target interval;

[0021] Obtaining a first function through signal accumulation, where the first function is an autocorrelation function of the navigation signal received within a target interval;

[0022] estimating the parameters of the multipath signal using the first function to obtain estimated multipath signal parameters;

[0023] The multipath signal parameters are used to identify the multipath signal in the target interval to obtain the operation result.

[0024] This example demonstrates the process of performing a single multipath signal identification operation and obtaining the result. It provides a feasible solution for setting up and operating a correlator for a single target interval. It ensures accurate estimation of multipath signal parameters while minimizing hardware correlator resources, thus reducing base station maintenance costs.

[0025] Optionally, estimating the parameters of the multipath signal by using the first function to obtain the estimated multipath signal parameters includes:

[0026] The main path signal parameters are estimated through the first function;

[0027] The first reconstruction function corresponding to the main path signal is obtained by fitting the main path signal parameters, where the first reconstruction function is the autocorrelation function of the reconstructed main path signal;

[0028] Subtracting the first function from the first reconstruction function to obtain a second function, where the second function is an autocorrelation function of the multipath signal to be estimated;

[0029] The multipath signal parameters are estimated through the second function.

[0030] In these examples, a process of estimating multipath signal parameters using the first function is given, which provides a parameter basis for identifying multipath signals in a target interval.

[0031] Optionally, after obtaining the second function, the method further includes:

[0032] When it is determined based on the curve shape of the second function that the multipath signal delay to be estimated exceeds the multipath delay range of the target interval, the operation result indicates that the multipath signal is not identified, and the multipath signal parameters include the multipath signal delay;

[0033] When it is determined by the curve shape of the second function that the multipath signal delay to be estimated does not exceed the multipath delay range of the target interval, calculating the target residual of the first function;

[0034] When the target residual amount does not exceed the multipath threshold, the operation result indicates that no multipath signal is identified;

[0035] When the target residual exceeds the multipath threshold, the step of estimating and obtaining multipath signal parameters is performed using a second function.

[0036] In addition to using multipath signal parameters to identify multipath signals in the target interval, this example also adds two auxiliary identification methods. The target residual of the first function and the curve shape of the second function can be used to quickly obtain the multipath identification operation results.

[0037] Optionally, performing multipath signal identification on the target interval using the multipath signal parameters to obtain an operation result includes:

[0038] A second reconstruction function corresponding to the multipath signal is obtained by fitting the multipath signal parameters, where the second reconstruction function is an autocorrelation function of the reconstructed multipath signal;

[0039] Iterate the first reconstruction function and the second reconstruction function until the parameters of the iterative loop satisfy the iteration condition, terminating the iterative loop, and obtaining the latest first reconstruction function and the latest second reconstruction function at the time of the termination of the iterative loop, as well as target multipath signal parameters corresponding to the latest first reconstruction function and the latest second reconstruction function;

[0040] Calculating a first residual using the latest first reconstruction function and the first function, and calculating a second residual using the latest first reconstruction function, the latest second reconstruction function, and the first function;

[0041] An effective determination of the multipath signal parameters is performed using the first residual amount, the second residual amount, and the target multipath parameter to obtain an operation result.

[0042] In this embodiment, multipath signal recognition is achieved with the help of the final result of the loop iteration, which helps to achieve accurate identification of multipath signals, thereby enabling real-time monitoring of the radio signal environment in which the reference station is located, reducing the manual maintenance cost of the reference station, and also reducing power consumption and saving costs.

[0043] Optionally, performing signal processing on the digital intermediate frequency signal to obtain signal accumulation values ​​corresponding to multiple correlators includes:

[0044] After mixing the digital intermediate frequency signal with the local carrier, loop tracking is performed to obtain the coherent integration values ​​of multiple correlators. The coherent integration values ​​of multiple correlators are as follows:

[0045]

[0046] Among them, X i is the coherent integration value of correlator i after stripping the secondary modulation code, I i For X i The in-phase signal, Q i is the orthogonal signal, A is the signal amplitude, M is the total number of sampling points within the coherent integration time, d i is the navigation message in the coherent integration value, τ is the phase difference between the satellite pseudo code and the local pseudo code, sinc(π·f Δ ·T I ) is the coherent integration loss caused by Doppler frequency offset, f Δ is the Doppler shift, T I is the coherent integration time, is the complex Gaussian white noise sequence output by the correlator, T Cis the length of one pseudo-random chip, R(τ) is the autocorrelation function of the spreading code;

[0047] The message symbols of the navigation message are stripped from the coherent integration values ​​of the multiple correlators, so that the multiple correlators respectively accumulate the coherent integration values ​​after stripping the message symbols, and obtain the signal accumulation values ​​corresponding to the multiple correlators. The signal accumulation values ​​are as follows

[0048]

[0049] in, is the cumulative value of the signal corresponding to correlator i, N is the cumulative number of messages for which a single correlator makes message symbol decisions, It is the complex Gaussian white noise sequence output by correlator i after stripping the message symbols.

[0050] In this example, a process of performing signal accumulation within a single target interval to obtain the signal accumulation value required for constructing the first function is given, which provides a reference for subsequent multipath signal parameter estimation.

[0051] In a second aspect, a multipath identification system is provided, the system comprising:

[0052] A first selection module is configured to select a target interval from N multipath delay intervals in a preset order, wherein the multipath delay ranges of the N multipath delay intervals do not overlap, and N is an integer greater than or equal to 2;

[0053] The identification module is used to identify the multipath signal of the target interval and obtain the identification result each time the target interval is selected;

[0054] The second selection module is configured to, when the identification result indicates that the target interval does not include a multipath signal, continue to select the next target interval from the N multipath delay intervals, and complete the single multipath signal identification process until the selected target interval includes a multipath signal.

[0055] In a third aspect, a multipath identification device is provided. The multipath identification device includes a memory, a processor, and a multipath identification program stored in the memory and running on the processor. The multipath identification program implements the steps of the multipath signal identification method of the first aspect.

[0056] In a fourth aspect, a computer storage medium is provided, which, when executed by a processor, implements the steps of the multipath signal identification method of the first aspect.

[0057] In a fifth aspect, a computer program product is provided. The computer program product includes a computer program. When the computer program is executed by a processor, the steps of the multipath signal identification method in the first aspect are implemented.

[0058] Compared to the prior art, the multipath signal identification method and related apparatus provided in the embodiments of the present application select a target interval from N multipath delay intervals in a preset order during a single multipath signal identification process. The multipath delay ranges of the N multipath delay intervals do not overlap, and N is an integer greater than or equal to 2. Each time a target interval is selected, multipath signal identification is performed on the target interval to obtain an identification result. If the identification result indicates that the target interval does not include a multipath signal, the next target interval is selected from the N multipath delay intervals, and the single multipath signal identification process is completed when the selected target interval includes a multipath signal. The multipath delay interval is divided into N intervals with different signal delays, and multipath signal identification is then performed in each of the N intervals in a time-sharing manner. This allows multipath signal identification to be completed using a small number of correlator resources. Compared to related technologies, this reduces the number of additional correlators, thereby alleviating the problem of prior art multipath signal identification methods consuming a large amount of additional correlator resources while improving accuracy, thereby reducing power consumption and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0060] Figure 1 This is a schematic flowchart of a multipath signal identification method according to an embodiment of the present invention.

[0061] Figure 2 This is a detailed schematic flow chart of performing multipath signal recognition on a target interval and obtaining a recognition result in a multipath signal recognition method according to an embodiment of the present invention.

[0062] Figure 3 This is a detailed schematic flow chart of performing the multipath signal identification operation in the multipath signal identification method according to an embodiment of the present invention.

[0063] Figure 4 FIG. 4 is a schematic block diagram of a multipath identification system according to an embodiment of the present invention.

[0064] Figure 5 It is a schematic block diagram of a multipath signal identification device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0065] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention.

[0066] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The embodiments will be described in detail below with reference to the accompanying drawings.

[0067] Multipath is caused by reflection and diffraction. When satellite signals travel through multiple paths to the receiving antenna, they are superimposed, distorting the RF signal. This can lead to code phase lock errors in the satellite receiver's signal tracking module. Digital signal processing can be used to suppress and eliminate multipath interference (also known as multipath interference).

[0068] Digital signal processing techniques for combating multipath interference are generally divided into two categories. The first category estimates the parameters of each multipath signal component (including attenuation amplitude, delay, and phase), and then uses these estimated parameters to correct the pseudoranges in the original observations, thereby identifying multipath interference. The second category does not use parameter estimation algorithms, but instead directly achieves multipath suppression and elimination by improving the loop code discriminator and correlator code spacing.

[0069] The first type of solution mentioned above includes the Multipath Estimating DelayLock Loop (MEDLL) solution. The MEDLL solution uses a multipath signal parameter estimation method that combines software and hardware. It usually sets up a group of narrow-spacing correlators (more than 10) on the receiving channel to sample and measure the main peak of the correlation function curve.

[0070] The MEDLL scheme uses the maximum likelihood estimation criterion to estimate the parameters of the main peak of the correlation function curve. The decision factor is the mean square error between the fitted autocorrelation function and the received autocorrelation function. When the mean square error is minimized, the multipath signal is estimated.

[0071] The inventors of this application have discovered that, in the case of multipath, under the minimum mean square error (MSE) criterion, the accuracy of the MSE largely determines the accuracy of parameter estimation. Further analysis reveals that the accuracy of the MSE is determined by the accuracy of the received autocorrelation function. Therefore, in related art, the accuracy of the received autocorrelation function curve is typically improved by increasing the number of sampling points of the autocorrelation function, that is, by increasing the number of correlators, thereby enhancing the accuracy of multipath signal parameter estimation.

[0072] In summary, in order to make the estimated multipath parameters more accurate, the related technology needs to use a large amount of additional correlator resources. Therefore, there is an objective problem that the multipath signal recognition method consumes a lot of additional correlator resources while improving the accuracy.

[0073] To address the above-mentioned problems, the present application proposes a multipath identification method and related apparatus, thereby utilizing the characteristics that the reference station position is fixed and the multipath in the received signal changes slowly. By adopting the concept of "time division multiplexing", on the basis of ensuring a narrow correlator spacing, the number of correlators is not blindly increased. Instead, N multipath delay intervals with non-overlapping multipath delay ranges are set. Multipath signal search and identification are performed serially between the intervals, thereby completing the estimation of multipath parameters with a small amount of additional correlator resources, helping to achieve accurate identification of multipath signals, thereby enabling real-time monitoring of the radio signal environment in which the reference station is located, playing a role in reducing the manual maintenance cost of the reference station, and also reducing power consumption and saving costs.

[0074] The following first introduces the multipath signal identification method of the present application.

[0075] See Figure 1 In one embodiment of the multipath signal identification method of the present application, the method includes:

[0076] S110 , selecting a target interval from N multipath delay intervals according to a preset order.

[0077] The multipath delay ranges of the N multipath delay intervals do not overlap, and N may be an integer greater than or equal to 2. For example, N may be equal to 3.

[0078] S120: Whenever a target interval is selected, multipath signal recognition is performed on the target interval to obtain a recognition result.

[0079] S130 , when the identification result indicates that the target interval does not include a multipath signal, continue selecting the next target interval from the N multipath delay intervals until the selected target interval includes a multipath signal, thereby completing the single multipath signal identification process.

[0080] The embodiment of the present application divides the multipath delay interval into N intervals with different signal delays, and then sequentially performs multipath signal identification in the N intervals in a time-sharing manner. As a result, multipath signal identification can be completed using a small amount of correlator resources. Compared with related technologies, the number of additional correlators is reduced, thereby alleviating the problem of the existing multipath signal identification method consuming a large amount of additional correlator resources while improving accuracy.

[0081] In some optional examples, in S110, before the receiver receives the navigation signal, the distribution [d0,1] of the correlator on the autocorrelation function curve (i.e., the identification interval of the multipath delay) can be divided into N multipath delay intervals according to the length of the multipath interference.

[0082] It should be noted that each multipath delay interval consists of two parts: one is the basic correlator in the receiver, and the other is an additional correlator used for multipath identification (i.e., the additional correlator). The basic correlators are distributed on both sides of the zero point, and the additional correlators correspond to the multipath identification part. Therefore, each multipath delay interval can be expressed as follows:

[0083] [d i,start ,d i,end ]={[d0,·d1,0,d2,d3],[d i,1 ,···,d i,n-1 ]} (1)

[0084] Taking N=3 as an example, the three multipath delay intervals may include a short delay interval, a medium delay interval, and a long delay interval. For example, the short delay interval can be expressed by the following formula (2). During initialization, multipath signal identification can be performed from the short delay interval.

[0085] [d short,start ,d short,end ]={[d0,·d1,0,d2,d3],[d short,1 ,···,d short,n-1 ]} (2)

[0086] The above-mentioned preset order can be: starting from the kth (k∈N)th multipath delay interval, sequentially selecting the target interval, or it can be in reverse order. It can also be that when it is determined that there is no multipath signal in a certain target interval, the next target interval is selected in a preferential manner according to the parameters involved in the multipath signal identification process. For example, according to the parameters involved, the next multipath delay interval of the current target interval is used as the next target interval.

[0087] In this example, by selecting target intervals one by one in a preset order, time-sharing selection of multipath delay intervals is achieved, which helps to subsequently use a smaller number of correlators to achieve identification of far more than N multipath delay ranges.

[0088] In some optional examples, in S120, the multipath signal identification of a single target interval can be implemented with reference to existing technologies. Figure 2 , you can also perform the following steps:

[0089] S210, starting a counter and repeatedly performing an operation of identifying multipath signals in a target interval;

[0090] S220, each time a recognition operation is completed, a corresponding operation result is obtained;

[0091] S230, if the operation result indicates that a multipath signal is identified, stopping the identification operation in the target interval and performing multipath verification on the target interval;

[0092] S240, when the multipath verification of the target interval passes, the identification result indicates that the target interval includes a multipath signal;

[0093] S250: If the operation result indicates that no multipath signal is identified, a counter is incremented by one, and the identification operation is repeatedly performed in the target interval until the accumulated count of the counter reaches a number threshold. Then, it is determined whether the number of all accumulated operation results indicating that no multipath signal is identified exceeds a number threshold, and the number threshold is less than or equal to the number threshold.

[0094] S260: When the number of all the accumulated operation results indicating that the multipath signal is not identified exceeds the number threshold, the identification result indicates that the target interval does not include the multipath signal.

[0095] During the multipath signal identification process for a single target interval, the multipath signal identification operation is repeated multiple times, with a counter counting the number of identification operations. If no multipath signal is detected during the identification operation within a set threshold, a check is performed to determine whether the total number of times a multipath signal was not identified during the identification operation exceeds a threshold. If so, it is determined that no multipath signal was identified, and the target interval can be switched. Conversely, if it is determined that the total number of times a multipath signal was not identified during the identification operation does not exceed the threshold, an error has been detected, the counter can be cleared, and multipath identification for the target interval can be repeated.

[0096] If a multipath signal is detected during a multipath signal identification operation within the set threshold, the identification operation is stopped and multipath verification is performed on the target interval. Only when a multipath signal is identified and the multipath verification passes is the multipath signal detected confirmed. If the multipath verification fails, the next multipath identification operation for the target interval can be continued.

[0097] For example, the multipath signal identification operation may be repeated ten times (a threshold number of times). If a multipath signal is identified in one of the identification operations during the identification process and the multipath verification of the target interval passes, the target interval is considered to include a multipath signal. If more than eight (a threshold number of times) of the ten identification operation results indicate that a multipath signal is not identified, the target interval is considered to include no multipath signal.

[0098] Optionally, the verification status of the verification strategy can also be set. Initially, the verification status can be set to zero. If a multipath signal is detected in a certain identification operation, the verification status can be set to one. If the subsequent multipath verification fails, the verification status can be reset to zero, thereby helping to timely understand the real-time multipath identification status of a single target interval.

[0099] Optionally, the multipath verification process for the target interval may include: performing multipath identification again based on the result of the current identification operation; if the two results are consistent, the multipath verification is determined to be passed; if the two results are inconsistent, the multipath verification is determined to be failed, thereby improving the accuracy of multipath identification.

[0100] In this example, by repeatedly performing the multipath signal identification operation multiple times, and then based on the results of multiple times of not identifying the multipath signal, combining the multipath signal verification operation after identifying the multipath signal, the accuracy of multipath identification in a single target interval can be improved, and flexible switching of the target interval can be achieved.

[0101] In other optional examples, the number threshold may not be set. When the operation result indicating that the multipath signal is not identified reaches the number threshold, the repetitive execution of the multipath signal identification operation is directly stopped, thereby confirming that the identification result of the target interval indicates that the target interval does not include a multipath signal.

[0102] This example provides another flexible and diverse solution for multipath signal identification in a target interval, which can improve the accuracy of multipath identification within a single target interval and realize flexible switching of target intervals.

[0103] In some alternative examples, see Figure 3 In the above S210, the process of performing the multipath signal identification operation may include:

[0104] S310, receiving a navigation signal and converting the navigation signal into a digital intermediate frequency signal;

[0105] S320, performing signal processing on the digital intermediate frequency signal through multiple correlators to obtain signal accumulation values ​​corresponding to the multiple correlators, wherein the identification intervals of the multiple correlators correspond to the target interval;

[0106] S330, obtaining a first function through signal accumulation, where the first function is an autocorrelation function of the navigation signal received within the target interval;

[0107] S340, estimating parameters of the multipath signal using the first function to obtain estimated multipath signal parameters;

[0108] S350: Perform multipath signal identification on the target interval using the multipath signal parameters to obtain an operation result.

[0109] This example demonstrates the process of performing a single multipath signal identification operation and obtaining the result. It provides a feasible solution for setting up and operating a correlator for a single target interval. It ensures accurate estimation of multipath signal parameters while minimizing hardware correlator resources, thus reducing base station maintenance costs.

[0110] In the above process, after the receiver receives the navigation signal, it can enter the loop tracking stage, mix the digital intermediate frequency signal converted from the navigation signal with the local carrier, and then multiply it with multiple leading, lagging and one timely local codes at the same time, thereby realizing loop tracking.

[0111] The local carrier includes the Doppler frequency estimated by the carrier loop, and the local code has the code phase estimated by the delay loop. The signal accumulation values ​​corresponding to multiple correlators can be obtained based on the coherent integration results during the loop tracking process.

[0112] The first function R can be fitted based on the signal accumulation values ​​of multiple correlators with an accumulation time of several seconds. rcv (τ) or the first function R rcv (τ), for example, the signal accumulation value of the accumulation time of 1 second is obtained, and then the function curve of the first function is obtained according to the signal accumulation value of each correlator. Finally, the first function R rcv (τ) is sent to the parameter estimation module of the multipath signal to estimate the multipath signal parameters, and determine whether the multipath signal is recognized in a single target interval based on the multipath signal parameters.

[0113] In some optional examples, performing signal processing on the digital intermediate frequency signal in S320 to obtain signal accumulation values ​​corresponding to multiple correlators may include:

[0114] S321, after mixing the digital intermediate frequency signal with the local carrier, loop tracking is performed to obtain the coherent integration values ​​of multiple correlators. The coherent integration values ​​of the multiple correlators are as follows:

[0115]

[0116] Among them, X iis the coherent integration value of correlator i after stripping the secondary modulation code, I i For X i The in-phase signal, Q i is the orthogonal signal, A is the signal amplitude, M is the total number of sampling points within the coherent integration time, d i is the navigation message in the coherent integration value, τ is the phase difference between the satellite pseudo code and the local pseudo code, sinc(π·f Δ ·T I ) is the coherent integration loss caused by Doppler frequency offset, f Δ is the Doppler shift, T I is the coherent integration time, is the complex Gaussian white noise sequence output by the correlator, T C is the length of one pseudo-random chip, and R(τ) is the autocorrelation function of the spreading code.

[0117] S322, stripping the message symbols of the navigation message from the coherent integration values ​​of the multiple correlators, so that the multiple correlators respectively accumulate the coherent integration values ​​after stripping the message symbols, and obtain the signal accumulation values ​​corresponding to the multiple correlators. The signal accumulation values ​​are as follows:

[0118]

[0119] in, is the cumulative value of the signal corresponding to correlator i, N is the cumulative number of messages for which a single correlator makes message symbol decisions, It is the complex Gaussian white noise sequence output by correlator i after stripping the message symbols.

[0120] It should be noted that after the digital intermediate frequency signal obtained by converting the navigation signal is mixed with the local carrier and then multiplied by multiple leading, lagging and one timely local codes respectively, the coherent integration result can be referred to the following formula (5).

[0121]

[0122] Where A is the signal amplitude, T s is the sampling period, d[kT s ] is the modulation data, v[kT s ] is the secondary modulation code, c[kT s ] is a pseudo code sequence, c[kT s +τ] is the local pseudo code sequence, τ is the phase difference between the input pseudo code and the local code, f Δ is the Doppler tracking error, n k is a complex white Gaussian noise sequence.

[0123] On this basis, x[k] can be integrated to complete bit synchronization. After stripping off the secondary modulation code, the coherent integration result at this time can be output, which can be expressed as the above formula (3). Since it is necessary to obtain the signal accumulation value, the navigation message symbol can be judged, thereby stripping off the message symbol, so that the correlator accumulates the complex Gaussian white noise sequence output, and the above formula (4) is obtained.

[0124] In this example, a process of performing signal accumulation within a single target interval to obtain the signal accumulation value required for constructing the first function is given, which provides a reference for subsequent multipath signal parameter estimation.

[0125] In some optional examples, the above-mentioned process of estimating multipath signal parameters through the first function may include: estimating the main path signal parameters through the first function; fitting the first reconstruction function corresponding to the main path signal through the main path signal parameters, the first reconstruction function being the autocorrelation function of the reconstructed main path signal; subtracting the first function from the first reconstruction function to obtain a second function, the second function being the autocorrelation function of the multipath signal to be estimated; and estimating the multipath signal parameters through the second function.

[0126] It should be noted that the first function R rcv (τ) is the autocorrelation function after the multipath signal is superimposed. The correlator can be used to sample and measure the main peak of the first function curve to estimate the main path signal X LOS (t) (or called the attenuation amplitude of the direct path signal) Delay and phase The attenuation amplitude of the main path signal Delay and phase That is the main path signal parameter.

[0127] After obtaining the main path signal parameters, the reconstructed main path signal X can be obtained by fitting LOS (t) is the autocorrelation function, i.e. the first reconstruction function The autocorrelation function R of the actual received navigation signal rcv (τ) minus the reconstructed main path signal X LOS Autocorrelation function of (t) The difference result is the multipath signal X to be estimated MP Autocorrelation function of (t) The second function (i.e. the multipath signal X to be estimated) can be correlated by a correlator. MP (t) autocorrelation function) R MPThe main peak waveform of the (τ) curve is sampled and measured, and then the maximum likelihood method is used for reverse deduction and estimation to obtain the attenuation amplitude, delay, and phase of each multipath signal. The attenuation amplitude, delay, and phase of the multipath signal are the multipath signal parameters.

[0128] In these examples, a process of estimating multipath signal parameters using the first function is given, which provides a parameter basis for identifying multipath signals in a target interval.

[0129] In some other optional examples, after obtaining the second function, the above method may further include:

[0130] When it is determined based on the curve shape of the second function that the multipath signal delay to be estimated exceeds the multipath delay range of the target interval, the operation result indicates that the multipath signal is not identified, and the multipath signal parameters include the multipath signal delay;

[0131] When it is determined by the curve shape of the second function that the multipath signal delay to be estimated does not exceed the multipath delay range of the target interval, calculating the target residual of the first function;

[0132] When the target residual amount does not exceed the multipath threshold, the operation result indicates that no multipath signal is identified;

[0133] When the target residual exceeds the multipath threshold, the step of estimating and obtaining multipath signal parameters is performed using a second function.

[0134] In addition to using multipath signal parameters to identify multipath signals in the target interval, this example also adds two auxiliary identification methods. The target residual of the first function and the curve shape of the second function can be used to quickly obtain the multipath identification operation results.

[0135] Among them, using the second function R MP The curve shape of (τ) can quickly identify the situation where the multipath signal is obviously not in the multipath signal delay interval. If the curve shape cannot clearly identify the multipath signal is not in the multipath signal delay interval, the residual estimation method can be used to determine whether there is a multipath signal. The target residual of the actual autocorrelation function (i.e., the first function) can be calculated using the following formula (6).

[0136]

[0137] Where N is the number of correlators, R x (τ) represents the actual autocorrelation function curve, R(τ) represents the reference autocorrelation function, τ k Represents R x The kth sampling point of (τ), represents the amplitude of the i-th signal, represents the delay of the i-th signal, represents the phase of the i-th signal, where

[0138]

[0139] If the target residual amount does not exceed the multipath threshold, it can be confirmed that the operation result indicates that no multipath signal is identified. Otherwise, the process enters the second function to estimate the multipath signal parameters and then realize the multipath identification process.

[0140] It should also be noted that in this process, the target residual amount and / or the shape of the second function curve can be evaluated to determine whether the multipath signal is in the multipath delay interval on the front side of the target interval or the multipath delay interval on the next side. This can achieve a preferential selection of the multipath delay interval and ensure that the target interval configuration corresponding to the correlator can be switched to the expected sampling position, thereby realizing regional multipath signal identification.

[0141] Still taking the multipath delay interval including the short delay interval, the medium delay interval and the long delay interval as an example, for example, when the target interval is the long delay interval, it can be determined based on the curve shape of the second function that the current target interval does not identify the multipath signal, but the curve shape can determine that the multipath count does not meet the short multipath condition, and the target interval can be switched to the medium delay interval.

[0142] In some further optional examples, the multipath signal identification of the target interval using the multipath signal parameters to obtain the operation result may include:

[0143] A second reconstruction function corresponding to the multipath signal is obtained by fitting the multipath signal parameters, where the second reconstruction function is an autocorrelation function of the reconstructed multipath signal;

[0144] Iterate the first reconstruction function and the second reconstruction function until the parameters of the iterative loop satisfy the iteration condition, terminating the iterative loop, and obtaining the latest first reconstruction function and the latest second reconstruction function at the time of the termination of the iterative loop, as well as target multipath signal parameters corresponding to the latest first reconstruction function and the latest second reconstruction function;

[0145] Calculating a first residual using the latest first reconstruction function and the first function, and calculating a second residual using the latest first reconstruction function, the latest second reconstruction function, and the first function;

[0146] An effective determination of the multipath signal parameters is performed using the first residual amount, the second residual amount, and the target multipath parameter to obtain an operation result.

[0147] In this embodiment, multipath signal recognition is achieved with the help of the final result of the loop iteration, which helps to achieve accurate identification of multipath signals, thereby enabling real-time monitoring of the radio signal environment in which the reference station is located, reducing the manual maintenance cost of the reference station, and also reducing power consumption and saving costs.

[0148] The above-mentioned iteration condition may include at least one of the following: the number of iterations reaches an iteration threshold, and the multipath signal parameters to be estimated corresponding to the first reconstruction function and the second reconstruction function meet the convergence condition.

[0149] Exemplarily, the iteration condition is that the difference between the multipath parameters (multipath delay, multipath phase, and multipath attenuation amplitude) of two previous iterations is less than a threshold value of 0.001.

[0150] The main path signal and one multipath signal parameter can be estimated in a loop iteration manner until the loop iteration condition is met, and then the loop is exited. At this time, the latest first reconstruction function and the latest second reconstruction function at the termination of the loop iteration can be output, as well as the target multipath signal parameters corresponding to the latest first reconstruction function and the latest second reconstruction function.

[0151] The iterative process may include: subtracting the autocorrelation function of the reconstructed multipath signal (i.e., the second reconstruction function) from the autocorrelation function of the received navigation signal to obtain the main path signal X to be estimated. LOS (t) autocorrelation function R LOS (τ). Then use the main path signal X to be estimated LOS (t) autocorrelation function R LOS (τ), estimate the main path signal X LOS Signal parameters of (t) Then, the first reconstruction function and the second reconstruction function are continuously reconstructed until the loop iteration is terminated.

[0152] At the end of the loop iteration, residual estimation and quality control methods can be used to determine the presence of multipath signals and calculate confidence. In this example, when making a valid determination, the residual, short-term statistics of multipath delay, and the relationship between the residual and multipath delay distribution can be used to perform quality control and confidence estimation of the estimation results.

[0153] The residual is calculated as SSR(n) = 1 / V(n), where the first residual SSR(1) represents the residual after estimating the main path signal (i.e., the first residual), and SSR(2) represents the residual after estimating the main path signal and one multipath signal (i.e., the second residual).

[0154] When calculating the first residual, the parameter V(1) involved is the sum of the differences between the latest first reconstruction function and each point of the first function. When calculating the second residual, the parameter V(2) involved is the sum of the differences between the latest second reconstruction function and the latest first reconstruction function and each point of the first function.

[0155] The above-mentioned conditions for effective determination can be set according to actual needs. For example, effective determination of multipath parameters can be achieved using at least one of the following reference conditions and / or parameters, ultimately obtaining an operation result. The at least one reference condition can include whether the first residual amount and the second residual amount exceed a set threshold. The at least one parameter can include the proportional relationship between the first residual amount and the second residual amount, the statistical value of the target multipath delay, and the multipath delay distribution relationship.

[0156] In other optional examples, the process of using the parameter estimation module to complete the attenuation amplitude, phase and delay estimation can refer to the following steps.

[0157] You can traverse the autocorrelation function fed into the parameter estimation module to find the maximum energy value τ max , and then use the inverse tangent method to obtain the phase of the signal to be estimated The obtained phase can be used Phase rotation is performed to concentrate the energy on the I branch, making it easier to estimate the delay and attenuation amplitude.

[0158] It should be noted that when performing delay estimation, a code phase detector is usually used. Using two sampling points on the autocorrelation function, the energy value maximum point τ can be calculated. max The deviation τ from the true peak position τ0 of the signal to be estimated Δ The multipath delay to be estimated is The code phase discriminator is calculated as follows (7).

[0159]

[0160] It should be noted that when searching in the sub-target interval, the distribution of the correlators is non-uniform. max When the points are unevenly distributed, the sampling interval d needs to be adjusted to ensure that the interval between the two sampling points is τ max The spacing is the same.

[0161] After the delay estimation is completed, the peak value related to the signal to be estimated can be obtained τ Δ The relevant sampling value at , which is proportional to the corresponding position of the reference correlation function, satisfies the following formula (8).

[0162]

[0163] From this, we can derive formula (9) and calculate the attenuation amplitude

[0164]

[0165] In the above example, the signal parameter estimation process of the parameter estimation module is given. Compared with related technologies, the correlator in this example adopts the non-uniformly distributed MEDLL algorithm, which is different from the traditional MEDLL algorithm. It can be applied to multipath delay intervals and solve the dependence of a single interval on all intervals.

[0166] Combined with the above Figures 1 to 3 , describes in detail the multipath signal identification method according to the embodiment of the present invention, and will be combined with Figure 4 , describes in detail the multipath identification system of an embodiment of the present invention.

[0167] See Figure 4 In one embodiment, the multipath identification system includes:

[0168] A first selection module 410 is configured to select a target interval from N multipath delay intervals in a preset order, wherein the multipath delay ranges of the N multipath delay intervals do not overlap, and N is an integer greater than or equal to 2;

[0169] The identification module 420 is configured to perform multipath signal identification on the target interval and obtain an identification result each time the target interval is selected;

[0170] The second selection module 430 is configured to, when the identification result indicates that the target interval does not include a multipath signal, continue to select the next target interval from the N multipath delay intervals, and complete the single multipath signal identification process until the selected target interval includes a multipath signal.

[0171] Optionally, the identification module may include:

[0172] an identification unit, configured to start a counter and repeatedly perform an identification operation on a multipath signal in a target interval;

[0173] An acquisition unit, configured to acquire a corresponding operation result each time a recognition operation is completed;

[0174] a verification unit configured to, if the operation result indicates that a multipath signal is identified, stop performing the identification operation in the target interval and perform multipath verification on the target interval; wherein, when the multipath verification on the target interval passes, the identification result indicates that the target interval includes a multipath signal;

[0175] The self-incrementing unit is configured to, if the operation result indicates that a multipath signal is not identified, increment a counter by one, and continue to repeatedly perform the identification operation in the target interval until the cumulative count of the counter reaches a number threshold, and then determine whether the number of all accumulated operation results indicating that the multipath signal is not identified exceeds the number threshold, and the number threshold is less than or equal to the number threshold; if so, the identification result indicates that the target interval does not include a multipath signal.

[0176] Optionally, the identification unit may include:

[0177] A receiving subunit, configured to receive a navigation signal and convert the navigation signal into a digital intermediate frequency signal;

[0178] a signal processing subunit, configured to perform signal processing on the digital intermediate frequency signal through a plurality of correlators to obtain signal accumulation values ​​corresponding to the plurality of correlators, wherein the identification intervals of the plurality of correlators correspond to the target interval;

[0179] an obtaining subunit, configured to obtain a first function through a signal accumulation value, where the first function is an autocorrelation function of the navigation signal received within a target interval;

[0180] an estimating subunit, configured to estimate the parameters of the multipath signal using a first function to obtain estimated multipath signal parameters;

[0181] The multipath identification subunit is used to perform multipath signal identification on the target interval through the multipath signal parameters to obtain an operation result.

[0182] Optionally, the estimation subunit is specifically used to estimate the main path signal parameters through a first function; fit a first reconstruction function corresponding to the main path signal through the main path signal parameters, and the first reconstruction function is the autocorrelation function of the reconstructed main path signal; subtract the first function from the first reconstruction function to obtain a second function, and the second function is the autocorrelation function of the multipath signal to be estimated; and estimate the multipath signal parameters through the second function.

[0183] Optionally, the estimation subunit is further specifically configured to, after obtaining the second function, when it is determined through the curve shape of the second function that the multipath signal delay to be estimated exceeds the multipath delay range of the target interval, the operation result indicates that the multipath signal is not identified, and the multipath signal parameters include the multipath signal delay; when it is determined through the curve shape of the second function that the multipath signal delay to be estimated does not exceed the multipath delay range of the target interval, calculate the target residual amount of the first function; when the target residual amount does not exceed the multipath threshold value, the operation result indicates that the multipath signal is not identified; when the target residual amount exceeds the multipath threshold value, estimate the multipath signal parameters through the second function.

[0184] Optionally, the multipath identification subunit is specifically used to fit a second reconstruction function corresponding to the multipath signal through the multipath signal parameters, where the second reconstruction function is the autocorrelation function of the reconstructed multipath signal; the first reconstruction function and the second reconstruction function are iterated in a loop until the parameters of the loop iteration meet the iteration conditions, the loop iteration terminates, and the latest first reconstruction function and the latest second reconstruction function at the time of the loop iteration termination are obtained, as well as the target multipath signal parameters corresponding to the latest first reconstruction function and the latest second reconstruction function; the first residual is calculated through the latest first reconstruction function and the first function, and the second residual is calculated through the latest first reconstruction function, the latest second reconstruction function and the first function; the multipath signal parameters are effectively determined through the first residual, the second residual and the target multipath parameters to obtain the operation result.

[0185] Optionally, the signal processing subunit is specifically used to perform loop tracking after mixing the digital intermediate frequency signal with the local carrier to obtain the coherent integration values ​​of multiple correlators. The coherent integration values ​​of the multiple correlators are as follows:

[0186]

[0187] Among them, X i is the coherent integration value of correlator i after stripping the secondary modulation code, I i For X i The in-phase signal, Q i is the orthogonal signal, A is the signal amplitude, M is the total number of sampling points within the coherent integration time, d i is the navigation message in the coherent integration value, τ is the phase difference between the satellite pseudo code and the local pseudo code, sinc(π·f Δ ·T I ) is the coherent integration loss caused by Doppler frequency offset, f Δ is the Doppler shift, T I is the coherent integration time, is the complex Gaussian white noise sequence output by the correlator, T C is the length of one pseudo-random chip, R(τ) is the autocorrelation function of the spreading code;

[0188] The signal processing subunit is further specifically used to strip the message symbols of the navigation message from the coherent integration values ​​of multiple correlators, so that multiple correlators respectively accumulate the coherent integration values ​​after stripping the message symbols to obtain the signal accumulation values ​​corresponding to the multiple correlators. The signal accumulation values ​​are as follows:

[0189]

[0190] in, is the cumulative value of the signal corresponding to correlator i, N is the cumulative number of messages for which a single correlator makes message symbol decisions, It is the complex Gaussian white noise sequence output by correlator i after stripping the message symbols.

[0191] Figure 5 The hardware structure diagram of the multipath signal identification device provided in the embodiment of the present application is shown, wherein the multipath signal identification device may include a processor 501 and a memory 502 storing computer program instructions.

[0192] Specifically, the processor 501 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0193] The memory 502 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 502 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 502 may include removable or non-removable (or fixed) media. Where appropriate, the memory 502 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 502 is a non-volatile solid-state memory.

[0194] The memory 502 may include read-only memory (ROM), flash memory devices, random access memory (RAM), magnetic disk storage media devices, optical storage media devices, electrical, optical, or other physical / tangible memory storage devices. Thus, generally, the memory 502 includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the methods according to the above aspects of the present disclosure.

[0195] The processor 501 reads and executes computer program instructions stored in the memory 502 to implement any one of the multipath signal identification methods in the above embodiments.

[0196] In one example, the multipath signal identification device may further include a communication interface 503 and a bus 510. Figure 5 As shown, the processor 501, the memory 502, and the communication interface 503 are connected via a bus 510 and communicate with each other.

[0197] The communication interface 503 is mainly used to implement communication between various modules, systems, devices, units and / or equipment in the embodiments of the present application.

[0198] Bus 510 comprises hardware, software or both, and the parts of multipath signal identification equipment are coupled to each other.For example, and not limitation, bus can comprise accelerated graphics port (AGP) or other graphics bus, enhanced industry standard architecture (EISA) bus, front side bus (FSB), hypertransport (HT) interconnection, industry standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations.In suitable cases, bus 510 can comprise one or more buses.Although the present application embodiment describes and shows specific bus, the application considers any suitable bus or interconnection.

[0199] The multipath signal recognition device can be based on the multipath signal recognition method to achieve the combination Figures 1 to 4 Described is a multipath signal identification method and system.

[0200] In conjunction with the multipath signal identification method in the above embodiments, embodiments of the present application may provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any of the multipath signal identification methods in the above embodiments is implemented.

[0201] In addition, in conjunction with the multipath signal identification method in the above embodiments, embodiments of the present application may provide a computer program product for implementation. The computer program product stores computer program instructions; when the computer program instructions are executed by a processor, any of the multipath signal identification methods in the above embodiments is implemented.

[0202] In this document, the term "and / or" simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0203] It should be understood that in the embodiments of the present invention, "B corresponding to A" means that B is associated with A and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B based solely on A; B can also be determined based on A and / or other information.

[0204] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A multipath signal identification method, characterized in that: include: Selecting a target interval from N multipath delay intervals in a preset order, wherein the multipath delay ranges of the N multipath delay intervals do not overlap, and N is an integer greater than or equal to 2; Whenever the target interval is selected, multipath signal recognition is performed on the target interval to obtain a recognition result; If the identification result indicates that the target interval does not include the multipath signal, continue selecting the next target interval from the N multipath delay intervals until the selected target interval includes the multipath signal, completing the single multipath signal identification process; The performing multipath signal identification on the target interval to obtain an identification result includes: Starting a counter and repeatedly performing an operation of identifying multipath signals in the target interval; Each time the identification operation is completed, a corresponding operation result is obtained; If the operation result indicates that the multipath signal is identified, stopping the identification operation in the target interval and performing multipath verification on the target interval; When the multipath verification of the target interval passes, the identification result indicates that the target interval includes the multipath signal; The performing of the identification operation of the multipath signal includes: receiving a navigation signal and converting the navigation signal into a digital intermediate frequency signal; performing signal processing on the digital intermediate frequency signal through a plurality of correlators to obtain signal accumulation values ​​corresponding to the plurality of correlators, wherein the identification intervals of the plurality of correlators correspond to the target interval; Obtaining a first function through the signal accumulation value, where the first function is an autocorrelation function of the navigation signal received within the target interval; estimating the parameters of the multipath signal using the first function to obtain estimated multipath signal parameters; Multipath signal identification is performed on the target interval using the multipath signal parameters to obtain the operation result.

2. The method according to claim 1, characterized in that The performing multipath signal identification on the target interval to obtain an identification result includes: If the operation result indicates that the multipath signal is not identified, incrementing the counter by one, and continuously repeating the identification operation in the target interval until the accumulated count of the counter reaches a number threshold, and determining whether the number of all accumulated operation results indicating that the multipath signal is not identified exceeds a number threshold, where the number threshold is less than or equal to the number threshold; If so, the identification result indicates that the target interval does not include the multipath signal.

3. The method according to claim 1, characterized in that The estimating the parameters of the multipath signal by using the first function to obtain the estimated multipath signal parameters includes: By using the first function, the main path signal parameters are estimated; fitting a first reconstruction function corresponding to the main path signal using the main path signal parameters, where the first reconstruction function is an autocorrelation function of the reconstructed main path signal; Subtracting the first function from the first reconstruction function to obtain a second function, where the second function is an autocorrelation function of the multipath signal to be estimated; The multipath signal parameters are estimated and obtained through the second function.

4. The method according to claim 3, characterized in that After obtaining the second function, the method further includes: When it is determined, based on the curve shape of the second function, that the multipath signal delay to be estimated exceeds the multipath delay range of the target interval, the operation result indicates that the multipath signal is not identified, and the multipath signal parameters include the multipath signal delay; When it is determined by the curve shape of the second function that the multipath signal delay to be estimated does not exceed the multipath delay range of the target interval, calculating the target residual of the first function; When the target residual amount does not exceed the multipath threshold, the operation result indicates that the multipath signal is not identified; When the target residual exceeds the multipath threshold, the step of estimating the multipath signal parameter by using the second function is executed.

5. The method according to claim 3, characterized in that The performing multipath signal identification on the target interval by using the multipath signal parameter to obtain the operation result includes: fitting a second reconstruction function corresponding to the multipath signal using the multipath signal parameters, where the second reconstruction function is an autocorrelation function of the reconstructed multipath signal; Iterating the first reconstruction function and the second reconstruction function until parameters of the iterative loop satisfy an iteration condition, terminating the iterative loop, and obtaining the latest first reconstruction function and the latest second reconstruction function at the time of the termination of the iterative loop, as well as target multipath signal parameters corresponding to the latest first reconstruction function and the latest second reconstruction function; Calculating a first residual using a latest first reconstruction function and the first function, and calculating a second residual using a latest first reconstruction function, a latest second reconstruction function, and the first function; The operation result is obtained by performing effective determination of the multipath signal parameters through the first residual amount, the second residual amount and the target multipath signal parameters.

6. The method according to claim 2, characterized in that The performing signal processing on the digital intermediate frequency signal to obtain signal accumulation values ​​corresponding to the plurality of correlators includes: The digital intermediate frequency signal is mixed with the local carrier and then loop tracking is performed to obtain the coherent integration values ​​of multiple correlators. The coherent integration values ​​of the multiple correlators are as follows: Among them, X i is the coherent integration value of correlator i after stripping the secondary modulation code, I i For X i The in-phase signal, Q i is the orthogonal signal, A is the signal amplitude, M is the total number of sampling points within the coherent integration time, d i is the navigation message in the coherent integration value, τ is the phase difference between the satellite pseudo code and the local pseudo code, sinc(π·f Δ ·T I ) is the coherent integration loss caused by Doppler frequency offset, f Δ is the Doppler shift, T I is the coherent integration time, is the complex Gaussian white noise sequence output by the correlator, R(τ) is the autocorrelation function of the spreading code; Stripping the message symbols of the navigation message from the coherent integration values ​​of the plurality of correlators, so that the plurality of correlators respectively accumulate the coherent integration values ​​after stripping the message symbols, and obtaining the signal accumulation values ​​corresponding to the plurality of correlators, the signal accumulation values ​​are as follows in, is the cumulative value of the signal corresponding to correlator i, N is the cumulative number of messages for which a single correlator makes message symbol decisions, It is the complex Gaussian white noise sequence output by correlator i after stripping the message symbols.

7. A multipath signal identification system, characterized in that: The multipath signal identification system includes: A first selection module is configured to select a target interval from N multipath delay intervals in a preset order, wherein the multipath delay ranges of the N multipath delay intervals do not overlap, and N is an integer greater than or equal to 2; an identification module, configured to perform multipath signal identification on the target interval each time the target interval is selected, and obtain an identification result; a second selection module configured to, if the identification result indicates that the target interval does not include the multipath signal, continue to select a next target interval from the N multipath delay intervals until the selected target interval includes the multipath signal, completing the single multipath signal identification process; The identification module is specifically used to: Starting a counter and repeatedly performing an operation of identifying multipath signals in the target interval; Each time the identification operation is completed, a corresponding operation result is obtained; If the operation result indicates that the multipath signal is identified, stopping the identification operation in the target interval and performing multipath verification on the target interval; When the multipath verification of the target interval passes, the identification result indicates that the target interval includes the multipath signal; The performing of the identification operation of the multipath signal includes: receiving a navigation signal and converting the navigation signal into a digital intermediate frequency signal; performing signal processing on the digital intermediate frequency signal through a plurality of correlators to obtain signal accumulation values ​​corresponding to the plurality of correlators, wherein the identification intervals of the plurality of correlators correspond to the target interval; Obtaining a first function through the signal accumulation value, where the first function is an autocorrelation function of the navigation signal received within the target interval; estimating the parameters of the multipath signal using the first function to obtain estimated multipath signal parameters; Multipath signal identification is performed on the target interval using the multipath signal parameters to obtain the operation result.

8. A multipath signal identification device, characterized in that: The multipath signal identification device includes a memory, a processor, and a multipath signal identification program stored in the memory and running on the processor. The multipath signal identification program executes the steps of the multipath signal identification method according to any one of claims 1 to 6.

9. A computer storage medium, characterized in that When the computer storage medium is executed by a processor, the steps of the multipath signal identification method according to any one of claims 1 to 6 are implemented.

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