A satellite navigation signal processing system

Abstract

This invention relates to the field of signal processing technology, specifically a satellite navigation signal processing system, comprising: a multi-dimensional data acquisition module, a space-time modeling module, an interference suppression processing module, and a signal output module. The multi-dimensional data acquisition module is used to acquire satellite navigation signals under polar high-altitude environments. The space-time modeling module is used to establish a joint space-time model of the satellite navigation signals and divide the propagation paths of the satellite navigation signals into space-time units. The interference suppression processing module is used to extract the space-time unit division data and perform interference detection and suppression processing on ice crystal cloud coherent multipath interference in the satellite navigation signals through a signal receiving device. The signal output module is used to output the interference-suppressed satellite navigation signal. This invention solves the problem in the prior art where it is difficult to effectively identify and compensate for ice crystal cloud interference, leading to a decrease in the positioning accuracy of the navigation system.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, specifically a satellite navigation signal processing system. Background Technology

[0002] In the polar high-altitude satellite navigation signal reception environment, existing technologies face the following challenges: the numerous tiny, regularly shaped ice crystal clouds in the polar stratosphere exert unique interference mechanisms on satellite navigation signals. Unlike traditional ground-based multipath interference, ice crystal clouds, as non-uniformly distributed, highly dynamic reflectors in the air, trigger multiple coherent reflections and scatterings, resulting in complex and variable signal propagation paths with spatiotemporal variations. This leads to severe fluctuations in signal amplitude and phase, as well as coherent interference. This interference is characterized by non-stationarity and strong coherence, which can easily cause the receiver's phase-locked loop to lose lock or experience cycle slips due to rapid phase jitter. This reduces the effectiveness of existing multipath suppression techniques such as narrow correlation and double-difference filtering. Existing signal processing methods are insufficient to effectively identify and compensate for ice crystal cloud interference, severely impacting the positioning accuracy and continuity of satellite navigation systems in polar environments. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that it is difficult to effectively identify and compensate for ice crystal clouds in the prior art, which leads to a decrease in the positioning accuracy of the navigation system. The present invention proposes a satellite navigation signal processing system.

[0004] To achieve the above objectives, the present invention provides a satellite navigation signal processing system comprising the following modules:

[0005] Multidimensional data acquisition module, spatiotemporal modeling module, interference suppression and processing module, and signal output module;

[0006] The multidimensional data acquisition module is used to acquire satellite navigation signals in polar high-altitude environments and preprocess the received satellite navigation signals to obtain multidimensional feature data including signal strength, carrier phase, code phase and Doppler frequency shift.

[0007] The space-time modeling module is used to establish a joint space-time model of satellite navigation signals and to divide the propagation path of satellite navigation signals into space-time units. By constructing a multi-dimensional parameter space including azimuth, elevation, time delay and Doppler shift, it describes the propagation behavior of satellite navigation signals in the ice crystal cloud environment.

[0008] The interference suppression processing module is used to extract space-time unit partitioning data and perform interference detection and interference suppression processing on ice crystal cloud coherent multipath interference in satellite navigation signals through signal receiving equipment.

[0009] The signal output module is used to output the satellite navigation signal after interference suppression processing.

[0010] Preferably, in the strategy configured by the space-time modeling module, the space-time unit division of the satellite navigation signal propagation path specifically includes: based on the configuration of the antenna array of the satellite navigation signal receiving device and the signal propagation characteristics after iterative calibration, the signal propagation path in the space-time model is divided into multiple space-time units according to four-dimensional parameters of azimuth angle, elevation angle, time delay and Doppler frequency shift, wherein the unit volume of each space-time unit is adapted to the signal coherence volume.

[0011] Preferably, the interference suppression processing module is configured with the following strategy:

[0012] B11: Extract the space-time unit partitioning data and establish the signal space-time unit coordinate system, the interference source distribution coordinate system, and the array response coordinate system of the satellite navigation signal receiving equipment;

[0013] B12: Interference detection and suppression processing of ice crystal cloud coherent multipath interference in navigation signals through satellite navigation signal receiving equipment;

[0014] B13: Transmit the processed signal features to the satellite navigation signal processing platform. The signal features include: the set of time delay differences between direct signals and multipath signals {Δτ}. p}, the set of phase perturbations caused by multipath and the set of Doppler frequency shifts {Δf r};

[0015] The total time delay difference between direct paths and multi-path paths is P, Δτ1, Δτ2...Δτ P These represent the delay differences from the 1st to the Pth time interval, respectively.

[0016] The total number of phase disturbances caused by multipath is Q. These represent the first to the Qth phase perturbation values, respectively.

[0017] The total number of Doppler frequency shifts is R, Δf1, Δf2...Δf R These represent the first to the Rth frequency shift values, respectively.

[0018] B14: Repeat steps B11-B13, and use the satellite navigation signal receiving equipment to perform interference detection on the ice crystal cloud coherent multipath interference of different satellite navigation signals to obtain the processed feature data of all visible satellite navigation signals.

[0019] Preferably, step B12 includes:

[0020] B121: Point the satellite navigation signal receiving device at any satellite navigation signal, in the space-time unit Signal acquisition and processing are performed on the device, including: opening all receiving channels and performing initial beamforming.

[0021] B122: Extract satellite navigation signal data obtained in this space-time unit and perform multipath interference component detection, including:

[0022] First, calculate the spatiotemporal covariance matrix R of the received satellite navigation signal. xx ;

[0023] For the spacetime covariance matrix R xx Eigenvalue decomposition yields the eigenvalue sequence {λ1, λ2, ..., λ3}. M} and its corresponding salient feature vectors {v1, v2...v M}, where M is the number of receive channels;

[0024] Synchronously, the ice crystal cloud interference coherence factor κ is defined as a quantitative index of the interference intensity under this unit. The specific calculation strategy for the ice crystal cloud interference coherence factor κ is as follows:

[0025]

[0026] Where, λ i This represents the i-th eigenvalue in the eigenvalue sequence;

[0027] Then, the signal correlation function output by the correlator in the satellite navigation signal receiving device is extracted, and the interference level is determined based on the signal correlation function and the ice crystal cloud interference coherence factor κ. Specifically:

[0028] When the signal correlation function is the dominant peak and has no sidelobes, and the ice crystal cloud interference coherence factor κ is below the first threshold κ. th1 When the time interval is short, it indicates that the multipath interference in that space-time unit is relatively weak, and the unit should be moved to the next space-time unit. And keep all channel parameters unchanged;

[0029] When the signal correlation function exhibits sidelobes or peak distortion, or when ice crystal cloud interference occurs, the coherence factor κ exceeds the second threshold κ. th2 When it is determined that there is strong ice crystal cloud coherent interference in the satellite navigation signal, the main feature vector v1 and other significant feature vectors are extracted, and step B123 is executed.

[0030] Preferably, step B12 further includes:

[0031] B123: Based on the significant feature vectors {v1, v2...v...} extracted in step B122 K Construct a space-time projection matrix P to suppress coherent multipath interference in ice crystal clouds;

[0032] Simultaneously, based on the characteristics of each distortion component on the detected unit, the time delay difference Δτ of the scattering unit is obtained. e Phase shift and frequency shift change Δf e The total number of scattering units identified on the interference detection unit is G;

[0033] B124: Based on B123, calculate the interference intensity factor I for each scattering unit. e and coherence index C e ;

[0034] B125: Apply the spacetime projection matrix P to the next spacetime unit. The guide vector Above, generate pre-computed beamforming weights w pre .

[0035] Preferably, step B12 further includes:

[0036] B126: Based on steps B123-B124, calculate the interference trend factor T for each scattering unit. e ;

[0037] B127: The channel weighting coefficient W to be applied to each channel n of the satellite navigation signal receiving equipment in the next space-time cell. n ;

[0038] B128: Extract the pre-calculated beamforming weights w from step B125. pre and the channel weight coefficient W output in step B127 n The two are then coupled to obtain a comprehensive adaptive weight;

[0039] When the satellite navigation signal receiving equipment acquires signals for the next space-time unit, the signal processing platform performs beamforming based on the comprehensive adaptive weights and simultaneously adjusts the bandwidth of the phase-locked loop adaptively based on the ice crystal cloud interference coherence factor κ and the unit scaling bandwidth.

[0040] Preferably, step B12 further includes:

[0041] B129: Repeat steps B122 to B128 to perform interference suppression processing on each space-time unit in sequence;

[0042] B1210: While performing beamforming, the parameters of the satellite navigation signal tracking loop are dynamically adjusted based on the ice crystal cloud interference coherence factor κ of the current space-time cell. Specifically, this includes:

[0043] When the ice crystal cloud interference coherence factor κ exceeds the third threshold κ th3When this occurs, the strong interference mode is automatically activated, and an extended Kalman filter is used to replace the current phase-locked loop for carrier tracking.

[0044] Preferably, the satellite navigation signal receiving device specifically includes N antenna array elements, supports three navigation frequency bands L1, L2, and L5, and each array element is connected to a software-defined radio channel. The operating status and filtering parameters of each channel of the signal receiving device are adaptively controlled by the signal processing platform.

[0045] Compared with existing technologies, this invention comprehensively improves the positioning accuracy, continuity, and reliability of satellite navigation systems in complex electromagnetic environments in polar regions, and overcomes the shortcomings of traditional multipath suppression techniques in responding insufficiently to spatiotemporal non-stationary interference. The specific technical effects of this invention are as follows:

[0046] 1. This invention achieves accurate localization and feature extraction of coherent multipath interference in polar ice crystal clouds by constructing a spatiotemporal joint model and performing high-dimensional parameter partitioning on the signal propagation path, significantly improving the spatiotemporal identification accuracy of interference sources.

[0047] 2. This invention employs an interference detection mechanism based on feature structure analysis and a spatiotemporal projection matrix construction method, which effectively suppresses the distortion effect of strong coherent interference on the signal correlation peak shape and ensures the measurement stability of wave phase.

[0048] 3. This invention adopts an adaptive coupling strategy that integrates beamforming weights and channel reliability weights to synchronously and dynamically adjust the phase-locked loop bandwidth and tracking algorithm. The system can maintain stable tracking of the phase-locked loop under severe phase jitter environment and avoid loss of lock and cycle slip. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] in:

[0051] Figure 1 This is a schematic diagram of the structure of a satellite navigation signal processing system according to the present invention;

[0052] Figure 2 This is a schematic diagram of an interference detection and interference suppression process according to the present invention. Detailed Implementation

[0053] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0054] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0055] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0056] Example 1:

[0057] like Figure 1 As shown, a satellite navigation signal processing system according to an embodiment of the present invention includes the following modules:

[0058] Multidimensional data acquisition module, spatiotemporal modeling module, interference suppression and processing module, and signal output module;

[0059] The multidimensional data acquisition module is used to acquire satellite navigation signals in polar high-altitude environments and preprocess the received satellite navigation signals to obtain multidimensional feature data including signal strength, carrier phase, code phase and Doppler frequency shift.

[0060] The multidimensional data acquisition module is configured with the following strategies:

[0061] A11: Construct an environmental simulation system for polar stratospheric ice crystal clouds, and perform environmental simulation preprocessing on satellite navigation signal receiving equipment. The environmental simulation preprocessing includes atmospheric environmental parameter simulation and ice crystal cloud characteristic simulation.

[0062] The atmospheric environmental parameter simulation includes: simulating ionospheric delay, tropospheric refraction, and atmospheric attenuation parameters in the polar region within the environmental simulation system;

[0063] The simulation of ice crystal cloud characteristics includes: simulating the generation of ice crystal clouds with different shapes, densities and spatial distributions, and simulating the scattering, reflection and coherent interference effects of navigation signals in the ice crystal clouds. The spatial distribution settings of the ice crystal clouds include: uniform distribution and non-uniform distribution.

[0064] The uniform distribution specifically refers to the ice crystal cloud being uniformly distributed in the simulated space, with an ice crystal diameter of d and a number density of ρ.

[0065] For example, in this embodiment, it should be noted that the mode is used to simulate a large-scale uniform ice crystal cloud environment;

[0066] The non-uniform distribution specifically refers to the fact that the ice crystal cloud is distributed in a layered or clustered manner in the simulated space, and the ice crystal particle size distribution satisfies the Weibull distribution, with shape parameter k and scale parameter λ.

[0067] For example, in this embodiment, it should be noted that the mode is used to simulate the complex and ever-changing ice crystal cloud structure in the real environment;

[0068] A12: With a fixed iterative calibration time interval, 10 polar signal reception simulations were performed on the satellite navigation signal receiving equipment to verify the performance of the satellite navigation signal receiving equipment under different ice crystal cloud environments.

[0069] A13: Complete the iterative calibration of the satellite navigation signal receiving equipment.

[0070] For example, in this embodiment, an iterative calibration strategy is provided, specifically as follows:

[0071] In the environmental simulation system, a standard test signal with known power and phase is injected into all channels of the receiving device. The difference between the measured amplitude of each channel and the average amplitude of all channels is measured and calculated to obtain the relative gain difference. The difference between the measured phase of each channel and the average phase of all channels is measured and calculated simultaneously to obtain the relative phase difference.

[0072] By iteratively adjusting the parameters of each channel, the output amplitude and phase of all channels are kept consistent. For example, in this embodiment, an adaptive iterative method based on the least mean square (LMS) algorithm is used to adjust the gain weight and phase compensation value of each channel. That is, according to the magnitude and direction of the current relative gain difference and phase difference, the error is gradually reduced to zero by adjusting in reverse according to a preset ratio.

[0073] The space-time modeling module is used to establish a joint space-time model of satellite navigation signals and to divide the propagation path of satellite navigation signals into space-time units. By constructing a multi-dimensional parameter space including azimuth, elevation, time delay and Doppler shift, it describes the propagation behavior of satellite navigation signals in the ice crystal cloud environment.

[0074] The strategy configured in the space-time modeling module specifically includes dividing the propagation path of satellite navigation signals into space-time units: based on the configuration of the antenna array of the satellite navigation signal receiving device and the signal propagation characteristics after iterative calibration, the signal propagation path in the space-time model is divided into multiple space-time units according to four-dimensional parameters of azimuth angle, elevation angle, time delay and Doppler frequency shift, wherein the unit volume of each space-time unit is adapted to the signal coherence volume.

[0075] For example, in this embodiment, it should be noted that in the interference analysis of satellite navigation signals, the interference of ice crystal clouds is not uniform, but comes from specific directions and times. This division method can accurately capture the multipath interference characteristics caused by ice crystal clouds.

[0076] The interference suppression processing module is used to extract space-time unit partitioning data and perform interference detection and interference suppression processing on ice crystal cloud coherent multipath interference in satellite navigation signals through signal receiving equipment.

[0077] The interference suppression processing module is configured with the following strategies:

[0078] B11: Extract the space-time unit partitioning data and establish the signal space-time unit coordinate system, the interference source distribution coordinate system, and the array response coordinate system of the satellite navigation signal receiving equipment;

[0079] For example, in this embodiment, the coordinates of each space-time unit in the signal space-time unit coordinate system are: Used to accurately locate the propagation position of satellite navigation signals in the space-time domain, where θ i Indicates the direction of arrival of satellite navigation signals in the horizontal direction; Indicates the direction of arrival of satellite navigation signals in the vertical direction; τ k Indicates the time it takes for the satellite navigation signal to reach the receiving device; f d This indicates the Doppler shift in signal frequency caused by the relative motion between the satellite, the reflector (i.e., the ice crystal cloud in this embodiment), and the receiving device.

[0080] For example, in this embodiment, the coordinates of each interference source in the interference source distribution coordinate system are (x... m ,y m ,z m ,v m ), used to characterize the spatial distribution and motion state of ice crystal cloud reflective sources, where x m ,y m ,z m v represents the physical coordinates of the interference source in three-dimensional space. m It is the relative radial velocity of the interference source;

[0081] The coordinates of each antenna in the array response coordinate system of the satellite navigation signal receiving device are used to describe the spatial layout characteristics of the receiving antennas. For example, (X... n ,Y n Z n () represents the physical coordinates of the nth antenna element in three-dimensional space;

[0082] B12: Interference detection and suppression processing of ice crystal cloud coherent multipath interference in navigation signals through satellite navigation signal receiving equipment;

[0083] B13: Transmit the processed signal features to the satellite navigation signal processing platform. The signal features include: the set of time delay differences between direct signals and multipath signals {Δτ}. p}, the set of phase perturbations caused by multipath and the set of Doppler frequency shifts {Δf r};

[0084] It should be noted that the signal characteristics are used to comprehensively evaluate the interference suppression effect and signal quality;

[0085] For example, in this embodiment, it should be noted that each multipath interference source contains several scattering units;

[0086] The total time delay difference between direct paths and multi-path paths is P, Δτ1, Δτ2...Δτ P These represent the delay differences from the 1st to the Pth time delays, respectively. It should be noted that the delay difference reflects the difference in the signal propagation path, Δτ. p The larger the value, the longer the reflection path;

[0087] The total number of phase disturbances caused by multipath is Q. These represent the first to the Qth phase perturbation values, respectively. It should be noted that because ice crystal reflection is coherent, it will superimpose with the direct satellite navigation signal, causing a drastic phase jump in the received signal. Therefore, in this embodiment, the phase perturbation reflects the influence of ice crystal cloud on the phase of satellite navigation signal.

[0088] The total number of Doppler frequency shifts is R, Δf1, Δf2...Δf R These represent the first to the Rth frequency shift values, respectively. It should be noted that the frequency shift reflects the influence of the ice crystal cloud's movement on the satellite navigation signal frequency; the faster the movement, the greater the frequency shift. r The larger;

[0089] B14: Repeat steps B11-B13, and use the satellite navigation signal receiving equipment to perform interference detection on the ice crystal cloud coherent multipath interference of different satellite navigation signals to obtain the processed feature data of all visible satellite navigation signals.

[0090] like Figure 2 As shown, step B12 includes:

[0091] B121: Point the satellite navigation signal receiving device at any satellite navigation signal, in the space-time unit Signal acquisition and processing are performed on the device, including: opening all receiving channels and performing initial beamforming.

[0092] B122: Extract satellite navigation signal data obtained in this space-time unit and perform multipath interference component detection, including:

[0093] First, calculate the spatiotemporal covariance matrix R of the received satellite navigation signal. xx ;

[0094] For the spacetime covariance matrix R xx Eigenvalue decomposition yields the eigenvalue sequence {λ1, λ2, ..., λ3}. M} and its corresponding salient feature vectors {v1, v2...v M}, where M is the number of receive channels;

[0095] For example, it should be noted that in this embodiment, the feature value sequence {λ1,λ2...λ} M Sort in descending order;

[0096] Synchronously, the ice crystal cloud interference coherence factor κ is defined as a quantitative index of the interference intensity under this unit. The specific calculation strategy for the ice crystal cloud interference coherence factor κ is as follows:

[0097]

[0098] Where, λ i This represents the i-th eigenvalue in the eigenvalue sequence;

[0099] It should be noted that when the principal eigenvalue λ1 is much larger than the sum of other eigenvalues, the κ value is very large, indicating the existence of a strongly dominant coherent interference source.

[0100] When multiple eigenvalues ​​are significant, i.e. when the κ value decreases, it indicates that the interference environment of the satellite navigation signal is complex and there are multiple scattering sources or strong noise.

[0101] Then, the signal correlation function output by the correlator in the satellite navigation signal receiving device is extracted, and the interference level is determined based on the signal correlation function and the ice crystal cloud interference coherence factor κ. Specifically:

[0102] When the signal correlation function is the dominant peak and has no sidelobes, and the ice crystal cloud interference coherence factor κ is below the first threshold κ. th1 When the time interval is short, it indicates that the multipath interference in that space-time unit is relatively weak, and the unit should be moved to the next space-time unit. And keep all channel parameters unchanged;

[0103] When the signal correlation function exhibits sidelobes or peak distortion, or when ice crystal cloud interference occurs, the coherence factor κ exceeds the second threshold κ. th2When it is determined that there is strong ice crystal cloud coherent interference in the satellite navigation signal, the main feature vector v1 (which corresponds to the strongest interference source) and other significant feature vectors are extracted, and step B123 is executed.

[0104] For example, in this embodiment, peak distortion includes: widening of the main peak, asymmetry, or the appearance of steps;

[0105] B123: Based on the significant feature vectors {v1, v2...v...} extracted in step B122 K (which corresponds to K strong interference sources), construct a space-time projection matrix P to suppress coherent multipath interference in ice crystal clouds;

[0106] For example, in this embodiment, a strategy for constructing a space-time projection matrix P is provided, specifically as follows:

[0107]

[0108] Where I is the identity matrix, v k This represents the eigenvector corresponding to the k-th strong interference source; Represents the eigenvector v k The conjugate transpose of;

[0109] Simultaneously, based on the characteristics of each distortion component on the detected unit, the time delay difference Δτ of the scattering unit is obtained. e Phase shift and frequency shift change Δf e The total number of scattering units identified on the interference detection unit is G;

[0110] It should be noted that the time delay difference Δτ e The ratio of the signal propagation path difference to the speed of light reflects the time difference in signal propagation; the phase shift... The frequency shift Δf is a function of the carrier phase and the path difference, reflecting the relationship between phase change and propagation path; e The Doppler frequency shift caused by relative motion reflects the influence of ice crystal cloud motion on signal frequency;

[0111] B124: Based on B123, calculate the interference intensity factor I for each scattering unit. e and coherence index C e ;

[0112] For example, in this embodiment, the calculation strategy for the interference intensity factor is as follows:

[0113]

[0114] Among them, I eThis is the interference intensity factor. It should be noted that the interference intensity factor comprehensively reflects the intensity characteristics of the interference.

[0115] R n,e (Δτ,Δf d ) represents the mutual ambiguity function between the signal received by the nth channel and the signal of the eth scattering unit, where N is the total number of channels;

[0116] For example, in this embodiment, the calculation strategy for the coherence index is as follows:

[0117]

[0118] Among them, C e As a coherence index, it should be noted that the coherence index characterizes the coherence properties of the interference.

[0119] It should be noted that the molecular part The denominator represents the total power that can be obtained when the signals from all channels are in perfect phase (i.e., completely coherent) when they are superimposed; the denominator represents the total power that can be obtained when the signals from all channels are completely incoherent when they are superimposed.

[0120] It should also be noted that when C e When R is 1, it means complete coherence, indicating that R is coherent with respect to all N channels. n,e The maximum value is achieved when the (0,0) values ​​are completely identical, meaning the scattering source is an ideal point source, and its signal has only a fixed phase difference across different channels; when C e A value of 0 indicates complete irrelevance; C e When C is greater than 0 and less than 1, e The closer C is to 1, the stronger the spatial coherence of the scattering source. e The closer it is to 0, the weaker the coherence.

[0121] B125: Apply the spacetime projection matrix P to the next spacetime unit. The guide vector Above, generate pre-computed beamforming weights w pre .

[0122] In this embodiment, it should be noted that the guide vector Describes the direction Delay τ′ k Frequency shift f′ d The response of an ideal plane wave signal on different array elements;

[0123] For example, in this embodiment, pre-computed beamforming weights w are generated. pre Specifically:

[0124] B126: Based on steps B123-B124, calculate the interference trend factor T for each scattering unit. e ;

[0125] For example, in this embodiment, the interference trend factor T e The specific calculation strategy is as follows:

[0126]

[0127] Where γ is an adjustable warning weight coefficient, which determines the importance of the warning signal; H() is an indicator function with an output value of 0 or 1;

[0128] It should be noted that I e This represents the interference intensity factor of the current environment. It is an indicator function. If the coherence index continues to increase, it means that the scattering source is becoming more concentrated and its destructiveness is increasing, so the interference trend factor also increases. It should also be noted that the form of [1+()] is to ensure that the amplification factor is always greater than or equal to 1.

[0129] B127: The channel weighting coefficient W to be applied to each channel n of the satellite navigation signal receiving equipment in the next space-time cell. n ;

[0130] For example, in this embodiment, a channel weighting coefficient W is provided. n The acquisition strategy is as follows:

[0131]

[0132] Where, d n,e This represents the spatially normalized distance between the nth channel and the eth scattering unit, where σ is an adjustment parameter.

[0133] It should be noted that the use of the max form is intended to characterize the determination of channel weights based on the most severe interference sources near the channel.

[0134] B128: Extract the pre-calculated beamforming weights w from step B125. pre and the channel weight coefficient W output in step B127 n The two are then coupled to obtain a comprehensive adaptive weight;

[0135] For example, in this embodiment, a coupling processing implementation strategy is provided, specifically, a comprehensive adaptive weight is obtained by calculating the Hadamard product of the two.

[0136] It should also be noted that the pre-calculated beamforming weight w output in step B125...pre The purpose is to generate a beam pattern in the beamformer that has gain in the desired direction of the next space-time cell. The technical problem it addresses is the spatial domain issue, including: where to form the beam and where to perform interference suppression; for the channel weighting coefficient W output in step B127... n Its purpose is to reduce or shut down the contribution of channels that are physically very close to strong interference sources, and it aims to identify contaminated antenna channels.

[0137] It should also be noted that by coupling the two processes, it is possible to suppress interference from specific directions in the spatial domain, and at the channel level, the impact of unreliable channels that may have already received strong interference signals can be weakened.

[0138] When the satellite navigation signal receiving equipment acquires signals for the next space-time unit, the signal processing platform performs beamforming based on the comprehensive adaptive weights and simultaneously adjusts the bandwidth of the phase-locked loop adaptively based on the ice crystal cloud interference coherence factor κ and the unit scaling bandwidth.

[0139] For example, the adaptive adjustment of the phase-locked loop bandwidth includes: when the ice crystal cloud interference coherence factor κ increases, the loop bandwidth is automatically narrowed according to the unit scaling bandwidth, in order to enhance the filtering effect and suppress phase noise; conversely, when the ice crystal cloud interference coherence factor κ decreases, the bandwidth is automatically widened according to the unit scaling bandwidth, in order to improve the ability to track dynamic signals and the response speed.

[0140] B129: Repeat steps B122 to B128 to perform interference suppression processing on each space-time unit in sequence;

[0141] B1210: While performing beamforming, the parameters of the satellite navigation signal tracking loop are dynamically adjusted based on the ice crystal cloud interference coherence factor κ of the current space-time cell. Specifically, this includes:

[0142] When the ice crystal cloud interference coherence factor κ exceeds the third threshold κ th3 When this occurs, the strong interference mode is automatically activated, and an extended Kalman filter is used to replace the current phase-locked loop for carrier tracking.

[0143] The signal output module is used to output the satellite navigation signal after interference suppression processing. Example 2:

[0144] This embodiment provides an electronic device, including: a processor and a memory, wherein the memory stores a computer program that can be called by the processor;

[0145] The processor runs the aforementioned satellite navigation signal processing system by calling computer programs stored in memory.

[0146] The electronic device can vary considerably depending on its configuration or performance. It may include one or more Central Processing Units (CPUs) and one or more memories, wherein the memory stores at least one computer program, which is loaded and executed by the processor to run the satellite navigation signal processing system provided in the above embodiment. The electronic device may also include other components for implementing its functions; for example, it may have wired or wireless network interfaces and input / output interfaces for data input and output. Details will not be elaborated upon in this embodiment. Embodiment Three:

[0147] This embodiment proposes a computer-readable storage medium on which an erasable and rewritable computer program is stored.

[0148] When a computer program runs on a computer device, it causes the computer device to run one of the aforementioned satellite navigation signal processing systems.

[0149] For example, computer-readable storage media can be read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage devices.

[0150] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0151] It should be understood that determining B based on A does not mean determining B solely based on A; it also means determining B based on A and / or other information.

[0152] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the flow or function according to the embodiments of the present invention is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. Computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired network and / or wireless network. A computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. Available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media. Semiconductor media can be solid-state drives.

[0153] In the several embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only one method, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0154] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0155] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0156] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above 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 one or more embodiments or examples.

Claims

1. A satellite navigation signal processing system, characterized in that, The system includes the following modules: Multidimensional data acquisition module, spatiotemporal modeling module, interference suppression and processing module, and signal output module; The multidimensional data acquisition module is used to acquire satellite navigation signals in polar high-altitude environments and preprocess the received satellite navigation signals to obtain multidimensional feature data including signal strength, carrier phase, code phase and Doppler frequency shift. The space-time modeling module is used to establish a joint space-time model of satellite navigation signals and to divide the propagation path of satellite navigation signals into space-time units. By constructing a multi-dimensional parameter space including azimuth, elevation, time delay and Doppler shift, it describes the propagation behavior of satellite navigation signals in the ice crystal cloud environment. The interference suppression processing module is used to extract space-time unit partitioning data and perform interference detection and interference suppression processing on ice crystal cloud coherent multipath interference in satellite navigation signals through signal receiving equipment. The interference suppression processing module is configured with the following strategies: B11: Extract the space-time unit partitioning data and establish the signal space-time unit coordinate system, the interference source distribution coordinate system, and the array response coordinate system of the satellite navigation signal receiving equipment; B12: Interference detection and suppression processing of ice crystal cloud coherent multipath interference in navigation signals through satellite navigation signal receiving equipment; B13: Transmit the processed signal features to the satellite navigation signal processing platform. These signal features include the set of time delay differences between direct and multipath signals. The set of phase perturbations caused by multipath and Doppler frequency shift variation set ; The total time delay difference between direct paths and multi-path paths is P. These represent the delay differences from the 1st to the Pth time interval, respectively. The total number of phase disturbances caused by multipath is Q. These represent the first to the Qth phase perturbation values, respectively. The total Doppler frequency shift is R. These represent the first to the Rth frequency shift values, respectively. B14: Repeat steps B11-B13, and use the satellite navigation signal receiving equipment to perform interference detection on the ice crystal cloud coherent multipath interference of different satellite navigation signals to obtain the processed feature data of all visible satellite navigation signals. The signal output module is used to output the satellite navigation signal after interference suppression processing.

2. The satellite navigation signal processing system according to claim 1, characterized in that, The strategy configured in the space-time modeling module specifically includes dividing the propagation path of satellite navigation signals into space-time units: based on the configuration of the antenna array of the satellite navigation signal receiving device and the signal propagation characteristics after iterative calibration, the signal propagation path in the space-time model is divided into multiple space-time units according to four-dimensional parameters of azimuth angle, elevation angle, time delay and Doppler frequency shift, wherein the unit volume of each space-time unit is adapted to the signal coherence volume.

3. A satellite navigation signal processing system according to claim 2, characterized in that, Step B12 includes: B121: Point the satellite navigation signal receiving device at any satellite navigation signal, in the space-time unit Signal acquisition and processing are performed on the device, including: opening all receiving channels and performing initial beamforming; in, Indicates the direction of arrival of satellite navigation signals in the horizontal direction; Indicates the direction of arrival of satellite navigation signals in the vertical direction; Indicates the time it takes for the satellite navigation signal to reach the receiving device; This indicates the Doppler shift in signal frequency caused by the relative motion between the satellite, the reflector, and the receiving equipment. B122: Extract satellite navigation signal data obtained in this space-time unit and perform multipath interference component detection, including: First, calculate the spatiotemporal covariance matrix of the received satellite navigation signal. ; spatiotemporal covariance matrix Perform eigenvalue decomposition to obtain the eigenvalue sequence. and its corresponding salient feature vectors , where M is the number of receiving channels; Synchronization, defining the ice crystal cloud interference coherence factor The ice crystal cloud interference coherence factor is a quantitative index of the interference intensity in this unit. The specific calculation strategy is as follows: ； in, This represents the i-th eigenvalue in the eigenvalue sequence; Then, the signal correlation function output by the correlator in the satellite navigation signal receiving device is extracted, and based on the signal correlation function and the ice crystal cloud interference coherence factor... The degree of interference is determined as follows: When the signal correlation function is the main peak and has no sidelobes, and ice crystal clouds interfere with the coherence factor Below the first threshold When the time interval is short, it indicates that the multipath interference in that space-time unit is relatively weak, and the unit should be moved to the next space-time unit. And keep all channel parameters unchanged; When the signal correlation function exhibits sidelobes or peak distortion, or ice crystal cloud interference with the coherence factor... Above the second threshold At that time, it was determined that the satellite navigation signal was subject to strong ice crystal cloud coherent interference, and the main feature vector was extracted. And other significant eigenvectors.

4. A satellite navigation signal processing system according to claim 3, characterized in that, Step B12 also includes: B123: Based on the significant feature vector extracted in step B122 Construct a space-time projection matrix P to suppress coherent multipath interference in ice crystal clouds; Simultaneously, based on the characteristics of each distortion component on the detected unit, the time delay difference of the scattering unit is obtained. Phase shift and frequency shift variation The total number of scattering units identified on the interference detection unit is G; B124: Based on B123, calculate the interference intensity factor for each scattering unit. and coherence indicators ; B125: Projecting the spacetime matrix Applied to the next spacetime unit The guide vector Above, generate pre-computed beamforming weights. .

5. A satellite navigation signal processing system according to claim 4, characterized in that, Step B12 also includes: B126: Based on steps B123-B124, calculate the interference trend factor for each scattering unit. ; B127: Predict the channel weighting coefficients that the satellite navigation signal receiving equipment needs to apply to each channel n in the next space-time cell. ; B128: Extract the pre-calculated beamforming weights output from step B125. and the channel weight coefficients output in step B127 The two are then coupled to obtain a comprehensive adaptive weight; While the satellite navigation signal receiving equipment acquires signals for the next space-time unit, the signal processing platform performs beamforming based on integrated adaptive weights and simultaneously adjusts the coherence factor based on ice crystal cloud interference. And the bandwidth of the phase-locked loop is adaptively adjusted by unit scaling bandwidth.

6. A satellite navigation signal processing system according to claim 5, characterized in that, Step B12 also includes: B129: Repeat steps B122 to B128 to perform interference suppression processing on each space-time unit in sequence; B1210: While performing beamforming, based on the ice crystal cloud interference coherence factor of the current space-time cell. Dynamically adjust the parameters of the satellite navigation signal tracking loop, specifically including: When ice crystal clouds interfere with coherence factors Exceeding the third threshold When this occurs, the strong interference mode is automatically activated, and an extended Kalman filter is used to replace the current phase-locked loop for carrier tracking.

7. A satellite navigation signal processing system according to claim 6, characterized in that, The satellite navigation signal receiving device specifically includes N antenna array elements, supports three navigation frequency bands: L1, L2, and L5, and each array element is connected to a software-defined radio channel. The operating status and filtering parameters of each channel of the signal receiving device are adaptively controlled by the signal processing platform.

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