Echo evaluation method and system for sea clutter equivalent simulation board

Abstract

The present invention discloses an echo evaluation method and system for a sea clutter equivalent simulation board. The method collects and preprocesses real sea clutter echo data and equivalent simulation board sea clutter data; performs effective data screening on the preprocessed real sea clutter echo data and the preprocessed equivalent simulation board sea clutter data; selects a set of real sea clutter representative data from the real sea clutter echo data that has passed the stability test, and selects a set of simulated sea clutter representative data from the equivalent simulation board sea clutter data that has passed the stability test; performs statistical analysis, calculates the statistical goodness of fit between the real sea clutter statistical data results and the simulated sea clutter statistical data results, and obtains an evaluation result. The present invention can test the echo simulation effect of the sea clutter equivalent simulation board device, and put the tested simulation board device into use to deepen the understanding of sea clutter characteristics, fill the gaps in measured data, and improve the simulation of real sea surface environments and the detection of sea surface targets.

Description

Technical Field

[0001] The present invention belongs to the technical field of sea clutter equivalent simulation, and in particular relates to an echo evaluation method and an evaluation system for a sea clutter equivalent simulation board. Background Art

[0002] When a radio fuze detects and identifies targets at sea, the received echo signal contains not only target information but also scattered echoes from the ocean background—sea clutter. Sea clutter significantly impacts target detection. To improve the radio fuze's target detection performance, it is necessary to analyze and study the characteristics of sea clutter to effectively suppress clutter interference.

[0003] The evaluation and analysis of sea clutter equivalent simulation boards is of great significance for radio fuze performance estimation, radio fuze system design, target detection, and remote sensing applications. The statistical and spectral characteristics of sea clutter are particularly important, and clutter is typically simulated using a probability density distribution function (PDF) model that describes the clutter backscatter coefficient, or statistical model. The most important aspect of sea clutter simulation is the mathematical model that describes the radio fuze environment. This environment is often modeled from the perspective of the amplitude probability density distribution function (APD), meaning that the radio fuze echo signal must conform to a certain amplitude probability distribution.

[0004] The Sea Clutter Equivalent Simulator facilitates sea clutter testing by simulating echoes. However, the simulated echoes must first be evaluated for quality, ensuring 85% consistency between the simulated echo characteristics and those of the actual sea surface. Currently, there is limited sea clutter test data, and sea clutter simulations often focus on wave shape. Simulation methods for sea clutter echoes often rely solely on modeling, without physical simulation. Therefore, there is a need to address the inability of existing technologies to verify the echo simulation performance of sea surface simulation devices. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problem that the prior art cannot detect the echo simulation effect of the sea surface simulation device, and proposes an echo evaluation method and evaluation system for a sea clutter equivalent simulation board.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for evaluating echoes of a sea clutter equivalent simulation board comprises the following steps:

[0008] Collecting and preprocessing real sea surface clutter echo data and equivalent simulation board sea clutter data to obtain preprocessed real sea surface clutter echo data and preprocessed equivalent simulation board sea clutter data;

[0009] Performing effective data screening on the pre-processed real sea clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain effective data, wherein the effective data includes the real sea clutter echo effective data and the equivalent simulation board sea clutter effective data;

[0010] Perform stability testing on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability test; perform stability testing on valid data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes the stability test;

[0011] Selecting a set of real sea clutter representative data from the real sea surface clutter echo data that has passed the stability test, and selecting a set of simulated sea clutter representative data from the equivalent simulation board sea clutter data that has passed the stability test, performing statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtaining real sea clutter statistical data results, real sea clutter statistical curve graphs, simulated sea clutter statistical data results, and simulated sea clutter statistical curve graphs;

[0012] The statistical curves of real sea clutter and simulated sea clutter are used for intuitive comparison, and the statistical goodness of fit between the statistical data of real sea clutter and the statistical data of simulated sea clutter is calculated to obtain the evaluation results.

[0013] Furthermore, performing a stability test on the effective data of the real sea surface clutter echo to obtain the real sea surface clutter echo data that passes the stability test comprises the following steps:

[0014] S11, dividing the sequence of valid data of the real sea surface clutter echo into a number of blocks according to the window length, each block including a number of data points, and there is no overlap between the blocks;

[0015] S12, calculating the mean of several data points in each block and the overall mean of the effective data of the real sea surface clutter echo;

[0016] S13, calculating the overall Allan variance using the means of several data points in each block;

[0017] S14, changing the window length and repeating S11-S13, and drawing the Allan variance standard curve according to the relationship between the Allan variance and the bilateral power spectral density;

[0018] S15, calculating the Allan variance random error, and calibrating the Allan variance random error on the Allan variance standard curve to obtain an Allan variance graph;

[0019] S16, calculating the cosine similarity of the Allan variance graphs of any two sets of real sea clutter echo valid data;

[0020] S17. Statistically analyze the values ​​of the overall Allan variance and the random error of the Allan variance. If both are smaller than the overall mean of the valid data of the real sea surface clutter echoes, and the cosine similarity of the Allan variance graphs of any two groups of valid data of the real sea surface clutter echoes is greater than a first preset value, the real sea surface clutter echo data passes the stability test, and the real sea surface clutter echo data that passes the stability test is obtained.

[0021] Furthermore, the mean of several data points in each block is calculated as follows:

[0022]

[0023] in, is the mean of several data points in each block, k is the block number, y is the sequence of valid data of real sea clutter echo, n is the number of data points in each block, and i is the number of data points; the mean value in each block is recorded as: , ...;

[0024] The overall mean value of the effective data of the real sea clutter echo is calculated as follows:

[0025]

[0026] in, is the overall mean of the effective data of the real sea clutter echo, and m is the total number of data points of the effective data of the real sea clutter echo;

[0027] The calculation of the overall Allan variance using the mean of several data points in each block is shown in the following formula:

[0028]

[0029] in, is the population Allan variance, is the mean of several data points in the k+1th block, is the mean of several data points in the kth block, is the total number of blocks.

[0030] Furthermore, performing a stability test on the effective sea clutter data of the equivalent simulation board to obtain the equivalent simulation board sea clutter data that passes the stability test comprises the following steps:

[0031] S21, dividing the sequence of effective sea clutter data of the equivalent simulation board into a number of blocks according to the window length, each block including a number of data points, and no overlap between blocks;

[0032] S22, calculating the mean of several data points in each block and the overall mean of the effective sea clutter data of the equivalent simulation board;

[0033] S23, calculating the overall Allan variance using the means of several data points in each block;

[0034] S24, changing the window length and repeating S21-S23, and drawing the Allan variance standard curve using the relationship between the Allan variance and the bilateral power spectral density;

[0035] S25, calculating the Allan variance random error, and calibrating the Allan variance random error on an Allan variance standard curve to obtain an Allan variance graph;

[0036] S26, calculating the cosine similarity of the Allan variance diagrams of any two sets of equivalent simulation board sea clutter effective data;

[0037] S27. Statistically analyze the values ​​of the overall Allan variance and the random error of the Allan variance. If both values ​​are smaller than the overall mean value of the effective sea clutter data of the equivalent simulation board, and the cosine similarity of the Allan variance graphs of any two groups of effective sea clutter data of the equivalent simulation board is greater than a second preset value, the equivalent simulation board sea clutter data passes the stability test, and equivalent simulation board sea clutter data that passes the stability test is obtained.

[0038] Furthermore, the Allan variance random error includes quantization noise, angle random walk, zero bias instability, angular rate random walk and angular rate slope;

[0039] The total Allan error is the sum of the Allan variance and random error sources as shown below:

[0040]

[0041] in, is the total Allan error, is the square of the quantization noise, is the square of the random walk angle, is the square of the zero-bias instability, is the square of the random walk rate, is the square of the angular rate ramp; Q is the error coefficient of quantization noise, N is the error coefficient of angle random walk, B is the error coefficient of zero bias instability, K is the error coefficient of angular rate random walk, and R is the error coefficient of angular rate ramp.

[0042] Furthermore, the calculation of the statistical goodness of fit is as follows:

[0043]

[0044] Among them, S is the statistical goodness of fit, is the data set after statistical normalization of the actual sea clutter statistical data results, is the data set after statistical normalization of the statistical data results of simulated sea clutter, and N is the number of statistical data points;

[0045] If the statistical goodness of fit is greater than 85%, the sea clutter equivalent simulation board is effective.

[0046] Furthermore, the preprocessing includes verification and correction, omission supplementation and unified data format, the valid data screening includes elimination of abnormal echo data, transmission pulse distance mismatch processing and IQ channel imbalance compensation processing, the abnormal echo data includes electromagnetic interference and data sampling saturation, and the statistical analysis includes calculation of probability density and calculation of cumulative probability density.

[0047] An echo evaluation system for a sea clutter equivalent simulation board, comprising:

[0048] A preprocessing data module is obtained, which is used to collect and preprocess the real sea surface clutter echo data and the equivalent simulation board sea clutter data to obtain the preprocessed real sea surface clutter echo data and the preprocessed equivalent simulation board sea clutter data;

[0049] The effective data screening module is used to screen the pre-processed real sea surface clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain the real sea surface clutter echo effective data and the equivalent simulation board sea clutter effective data;

[0050] a stability check module, configured to perform a stability check on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability check, and to perform a stability check on valid data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes the stability check, wherein the stability check adopts a stability check method combining Allan variance and cosine similarity algorithms;

[0051] a statistical analysis module for selecting a group of real sea clutter representative data from the real sea clutter echo data that has passed the stability test, and selecting a group of simulated sea clutter representative data from the equivalent simulation board sea clutter data that has passed the stability test, performing statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtaining real sea clutter statistical data results, real sea clutter statistical curve graphs, simulated sea clutter statistical data results, and simulated sea clutter statistical curve graphs;

[0052] The goodness of fit calculation module is used to make an intuitive comparison between the real sea clutter statistical curve and the simulated sea clutter statistical curve, and calculate the statistical goodness of fit between the real sea clutter statistical data results and the simulated sea clutter statistical data results to obtain the evaluation results.

[0053] An electronic device comprises a memory, a processor and a computer program stored in the memory and runnable on the processor. When the processor executes the computer program, the echo evaluation method of the sea clutter equivalent simulation board is implemented.

[0054] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for evaluating the echo of a sea clutter equivalent simulation board is implemented.

[0055] Compared with the prior art, the present invention has the following beneficial technical effects:

[0056] This invention proposes a method for evaluating the echo of a sea clutter equivalent simulation board. By studying the echo evaluation technology, the stability and validity of sea clutter test data are determined, the statistical characteristics of multiple data sets are compared, and simulation consistency is judged. This method can verify the echo simulation performance of the sea clutter equivalent simulation board device. Putting the verified simulation board device into use can deepen understanding of sea clutter characteristics, fill gaps in measured data, and improve the performance of simulating real sea environments, detecting sea targets, and optimizing target detection and imaging algorithms. The sea clutter equivalent simulation board echo evaluation technology has a simple algorithm, fast calculation speed, and strong universality, making it suitable for testing the echo simulation performance of various sea surface simulation devices.

[0057] Furthermore, the stability of the sea clutter echo data measured multiple times is tested by combining the Allan variance and cosine similarity method.

[0058] Furthermore, by comparing the statistical characteristic probability density and cumulative probability density of the two sets of data, a goodness of fit test is performed to achieve the purpose of testing the echo simulation effect of the sea clutter simulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings:

[0060] Figure 1 The present invention is a flow chart of an echo evaluation method for a sea clutter equivalent simulation board.

[0061] Figure 2 This is a structural diagram of an echo evaluation system of a sea clutter equivalent simulation board of the present invention.

[0062] Figure 3 This is an electronic device diagram of an echo evaluation method for a sea clutter equivalent simulation board according to the present invention.

[0063] Figure 4 Schematic diagram of the echo evaluation method of the sea clutter equivalent simulation board in an embodiment of the present invention.

[0064] Figure 5 Schematic diagram of saturation abnormal data in an embodiment of the present invention.

[0065] Figure 6 Schematic diagram of Allan variance in an embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0067] Example 1

[0068] See also Figure 1 , a method for evaluating echoes of a sea clutter equivalent simulation board, comprising the following steps:

[0069] Collecting and preprocessing real sea surface clutter echo data and equivalent simulation board sea clutter data to obtain preprocessed real sea surface clutter echo data and preprocessed equivalent simulation board sea clutter data;

[0070] Performing effective data screening on the pre-processed real sea clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain effective data, wherein the effective data includes the real sea clutter echo effective data and the equivalent simulation board sea clutter effective data;

[0071] Perform stability testing on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability test; perform stability testing on valid data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes the stability test;

[0072] Selecting a set of real sea clutter representative data from the real sea surface clutter echo data that has passed the stability test, and selecting a set of simulated sea clutter representative data from the equivalent simulation board sea clutter data that has passed the stability test, performing statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtaining real sea clutter statistical data results, real sea clutter statistical curve graphs, simulated sea clutter statistical data results, and simulated sea clutter statistical curve graphs;

[0073] The statistical curves of real sea clutter and simulated sea clutter are used for intuitive comparison, and the statistical goodness of fit between the statistical data of real sea clutter and the statistical data of simulated sea clutter is calculated to obtain the evaluation results.

[0074] This embodiment collects and preprocesses real sea clutter echo data and sea clutter data from an equivalent simulation board, and performs effective data screening and stability testing to ensure that the data used for evaluation is accurate and reliable, thereby improving the accuracy of the evaluation results. A visual comparison of the real sea clutter statistical curve and the simulated sea clutter statistical curve clearly reveals the differences and similarities between the two. This intuitiveness makes the evaluation process easier to understand and operate. By calculating the statistical goodness of fit between the real sea clutter statistical data and the simulated sea clutter statistical data, a quantitative evaluation result is obtained, making the evaluation process more objective and measurable, and helping to determine whether the sea clutter equivalent simulation board is effective.

[0075] Performing a stability test on valid data of real sea surface clutter echoes to obtain real sea surface clutter echo data that passes the stability test includes the following steps:

[0076] S11, dividing the sequence of valid data of the real sea surface clutter echo into a number of blocks according to the window length, each block including a number of data points, and there is no overlap between the blocks;

[0077] S12, calculating the mean of several data points in each block and the overall mean of the effective data of the real sea surface clutter echo;

[0078] S13, calculating the overall Allan variance using the means of several data points in each block;

[0079] S14, changing the window length and repeating S11-S13, and drawing the Allan variance standard curve according to the relationship between the Allan variance and the bilateral power spectral density;

[0080] S15, calculating the Allan variance random error, and calibrating the Allan variance random error on the Allan variance standard curve to obtain an Allan variance graph;

[0081] S16, calculating the cosine similarity of the Allan variance graphs of any two sets of real sea clutter echo valid data;

[0082] S17. Statistically analyze the values ​​of the overall Allan variance and the random error of the Allan variance. If both are smaller than the overall mean of the valid data of the real sea surface clutter echoes, and the cosine similarity of the Allan variance graphs of any two groups of valid data of the real sea surface clutter echoes is greater than a first preset value, the real sea surface clutter echo data passes the stability test, and the real sea surface clutter echo data that passes the stability test is obtained.

[0083] The mean of several data points within each block is calculated as follows:

[0084]

[0085] in, is the mean of several data points in each block, k is the block number, y is the sequence of valid data of real sea clutter echo, n is the number of data points in each block, and i is the number of data points; the mean value in each block is recorded as: , ...;

[0086] The overall mean value of the effective data of real sea surface clutter echo is calculated as follows:

[0087]

[0088] in, is the overall mean of the effective data of the real sea clutter echo, and m is the total number of data points of the effective data of the real sea clutter echo;

[0089] The overall Allan variance is calculated using the mean of several data points in each block as shown below:

[0090]

[0091] in, is the population Allan variance, is the mean of several data points in the k+1th block, is the mean of several data points in the kth block, is the total number of blocks.

[0092] Performing a stability test on the effective sea clutter data of the equivalent simulation board to obtain the equivalent simulation board sea clutter data that passes the stability test includes the following steps:

[0093] S21, dividing the sequence of effective sea clutter data of the equivalent simulation board into a number of blocks according to the window length, each block including a number of data points, and no overlap between blocks;

[0094] S22, calculating the mean of several data points in each block and the overall mean of the effective sea clutter data of the equivalent simulation board;

[0095] S23, calculating the overall Allan variance using the means of several data points in each block;

[0096] S24, changing the window length and repeating S21-S23, and drawing the Allan variance standard curve using the relationship between the Allan variance and the bilateral power spectral density;

[0097] S25, calculating the Allan variance random error, and calibrating the Allan variance random error on an Allan variance standard curve to obtain an Allan variance graph;

[0098] S26, calculating the cosine similarity of the Allan variance diagrams of any two sets of equivalent simulation board sea clutter effective data;

[0099] S27. Statistically analyze the values ​​of the overall Allan variance and the random error of the Allan variance. If both values ​​are smaller than the overall mean value of the effective sea clutter data of the equivalent simulation board, and the cosine similarity of the Allan variance graphs of any two groups of effective sea clutter data of the equivalent simulation board is greater than a second preset value, the equivalent simulation board sea clutter data passes the stability test, and equivalent simulation board sea clutter data that passes the stability test is obtained.

[0100] Allan variance random errors include quantization noise, angle random walk, bias instability, angular rate random walk, and angular rate ramp;

[0101] The total Allan error is the sum of the Allan variance and random error sources as shown below:

[0102]

[0103] in, is the total Allan error, is the square of the quantization noise, is the square of the random walk angle, is the square of the zero-bias instability, is the square of the random walk rate, is the square of the angular rate ramp; Q is the error coefficient of quantization noise, N is the error coefficient of angle random walk, B is the error coefficient of zero bias instability, K is the error coefficient of angular rate random walk, and R is the error coefficient of angular rate ramp.

[0104] The goodness of fit statistic is calculated as follows:

[0105]

[0106] Among them, S is the statistical goodness of fit, is the data set after statistical normalization of the actual sea clutter statistical data results, is the data set after statistical normalization of the statistical data results of simulated sea clutter, and N is the number of statistical data points;

[0107] If the statistical goodness of fit is greater than 85%, the sea clutter equivalent simulation board is effective.

[0108] If the evaluation results show that the statistical goodness of fit is less than 85%, it indicates that the sea clutter equivalent simulation board is not effective and needs to be optimized or improved. This provides an effective feedback mechanism, which helps promote the continuous advancement and improvement of sea clutter equivalent simulation board technology. By accurately evaluating the effectiveness of sea clutter equivalent simulation boards, it can ensure that the radar system can accurately identify and track targets in actual applications, thereby improving the performance and reliability of the radar system.

[0109] Preprocessing includes verification and correction, supplementation of omissions and unification of data format. Effective data screening includes elimination of abnormal echo data, transmission pulse distance mismatch processing and IQ channel imbalance compensation processing. Abnormal echo data includes electromagnetic interference and data sampling saturation. Statistical analysis includes calculation of probability density and calculation of cumulative probability density.

[0110] Example 2

[0111] See also Figure 2 , an echo evaluation system for a sea clutter equivalent simulation board, comprising:

[0112] A preprocessing data module is obtained, which is used to collect and preprocess the real sea surface clutter echo data and the equivalent simulation board sea clutter data to obtain the preprocessed real sea surface clutter echo data and the preprocessed equivalent simulation board sea clutter data;

[0113] The effective data screening module is used to screen the pre-processed real sea surface clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain the real sea surface clutter echo effective data and the equivalent simulation board sea clutter effective data;

[0114] a stability check module, configured to perform a stability check on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability check, and to perform a stability check on valid data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes the stability check, wherein the stability check adopts a stability check method combining Allan variance and cosine similarity algorithms;

[0115] a statistical analysis module for selecting a group of real sea clutter representative data from the real sea clutter echo data that has passed the stability test, and selecting a group of simulated sea clutter representative data from the equivalent simulation board sea clutter data that has passed the stability test, performing statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtaining real sea clutter statistical data results, real sea clutter statistical curve graphs, simulated sea clutter statistical data results, and simulated sea clutter statistical curve graphs;

[0116] The goodness of fit calculation module is used to make an intuitive comparison between the real sea clutter statistical curve and the simulated sea clutter statistical curve, and calculate the statistical goodness of fit between the real sea clutter statistical data results and the simulated sea clutter statistical data results to obtain the evaluation results.

[0117] This embodiment, through a modular design, automates the entire evaluation process from data preprocessing to final evaluation results, improving evaluation efficiency and accuracy while reducing the complexity and error rate of manual operations. Through the data preprocessing module and the valid data screening module, the system ensures the high quality and validity of the data used for evaluation, reduces the impact of noise and outliers on the evaluation results, and improves the reliability of the evaluation. The stability verification module comprehensively assesses data stability, ensuring that the data used for statistical analysis is stable and reliable. The statistical analysis module generates statistical curves and graphs, providing rich information for the evaluation, understanding the characteristics, differences, and similarities between real and simulated sea clutter. The goodness of fit calculation module provides intuitive and quantitative results for evaluation by visually comparing the statistical curves of real sea clutter and simulated sea clutter, and calculating the statistical goodness of fit. It can quickly determine whether the sea clutter equivalent simulation board is effective and provide a basis for subsequent optimization and improvement. The application of this evaluation system helps to promote the continuous progress and improvement of sea clutter equivalent simulation board technology. Through continuous evaluation and optimization, the performance of the sea clutter equivalent simulation board can be improved, making it more accurately simulate the clutter characteristics of the real sea surface, providing better support for the design and testing of radar systems.

[0118] Example 3

[0119] See also Figure 3 , an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the echo evaluation method of the sea clutter equivalent simulation board described in the first embodiment is implemented.

[0120] Example 4

[0121] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the echo evaluation method for a sea clutter equivalent simulation board described in embodiment 1.

[0122] Example 5

[0123] A method for evaluating the echo of a sea clutter equivalent simulation board includes the following steps:

[0124] The evaluation principle of this embodiment is to first study the scattering characteristics of the sea surface. The sea surface is a type of random rough surface, and the research content of the electromagnetic scattering theory of random rough surfaces also includes the study of electromagnetic scattering from the sea surface. For a specific extended target (such as the sea surface), the radio fuse scattering cross section or radio fuse scattering coefficient is often used to characterize the strength of its electromagnetic wave scattering ability, which is a dimensionless parameter. Due to the randomness of the sea surface, the electromagnetic scattering characteristics of a large number of rough sea surfaces under certain sea conditions are usually studied from a statistical perspective to analyze the distribution characteristics of sea clutter. In the process of simulating the sea surface radio fuse echo, the changes in the radio fuse echo of the sea surface scattering element within the coherence time must be considered, and the sea surface is cumulatively averaged over time.

[0125] See also Figure 4 The echo evaluation method of the sea clutter equivalent simulation board mainly includes five steps. First, the multiple groups of data obtained from the real sea clutter echo and the simulation board device echo test are preprocessed. Then, the preprocessed data are screened to ensure the validity of the data. Then, the stability of each group of data is tested by Allan variance and cosine similarity to make the data representative and valid. Finally, the probability density PDF and cumulative probability density CDF of the data are statistically analyzed and calculated, and the calculation results are compared to complete the goodness of fit test.

[0126] Conduct multiple (3 or more) measurements in the target sea area on the same day for at least three days using telemetry to obtain multiple (at least 9) sets of sea clutter echo data. Conduct the same test on the installed sea clutter equivalent simulation board to obtain multiple (at least 9) sets of sea clutter echo data using telemetry. The measurement equipment, method, and time for each set of data are consistent, and all data are recorded and stored.

[0127] Step 1: Data preprocessing.

[0128] The collected real sea surface clutter echo data and the equivalent simulation board sea clutter data are preprocessed, including verifying and correcting the recorded data and supplementing omissions, organizing all experimental data, unifying the data format, and ensuring data integrity.

[0129] Step 2: Data screening

[0130] The pre-processed data is screened to remove abnormal echo data such as electromagnetic interference, data sampling saturation, etc. Figure 5 As shown, the transmission pulse distance mismatch, IQ channel imbalance compensation, etc. are processed to ensure the validity of the data.

[0131] Step 3: Data stability test

[0132] Sea surface fluctuations are primarily composed of gravity waves and capillary waves. The causes of sea clutter are complex and can be affected by factors such as temperature, tides, and changes in the natural environment. To verify the stability of sea clutter data under these factors and whether it effectively represents the sea clutter characteristics of the real sea surface and the simulation board device, this paper uses a method combining the Allan variance and cosine similarity algorithms to conduct the test.

[0133] The Allan variance method is a time-domain analysis technique that uses a sequence of differences between two adjacent sets of data, ultimately calculating the variance of all these differences to produce an Allan curve, which can be used to verify the stability of the data or device. While the classic variance method can only analyze errors at a global level, the Allan variance method can be used to analyze the mathematical characteristics of the underlying random processes that cause the errors. This not only helps identify the sources of known error terms in the observed data, but also helps determine other internal sources of error with unknown causes. Furthermore, the Allan variance method removes short-term uncertainties by averaging within blocks and removes long-term uncertainties by taking differences between adjacent blocks. Therefore, this embodiment uses the Allan variance method to verify the stability of sea clutter data.

[0134] The specific method for stability testing of real sea clutter data includes the following steps:

[0135] (1) Data segmentation

[0136] By window length The processed sea clutter data sequence y is divided into Clusters, each containing n data points, with no overlap between clusters.

[0137] (2) Find the average

[0138] Calculate the mean of n data points in each block respectively, ;

[0139] The mean value in each block is recorded as: , ,……

[0140] Find the overall mean of sea clutter data, a total of m points, ;

[0141] (3) Calculate the Allan variance

[0142] Blocked Allan Variance :

[0143]

[0144] Overall Allan variance:

[0145]

[0146] (4) Draw the Allan variance standard curve

[0147] The relationship between the Allan variance and the bilateral power spectral density is:

[0148]

[0149] is the power spectral density of the bilateral rate noise, that is, the power spectral density of the stationary random process. For non-stationary processes, the time-averaged power spectral density needs to be used.

[0150] The sea clutter random process can be tested for stability by varying τ. The Allan variance can be used to identify and quantify the various noise terms in the sea clutter data, which can then be used to determine the stability of the sea clutter data. and the square root of the Allan variance The log-log double logarithmic curve was used for further analysis.

[0151] Changing block length , repeat the above steps (1) to (3) to draw the double logarithmic curve of the Allan standard deviation changing with the block length, that is, the Allan variance curve, as shown in Figure 6 As shown in the figure, each time block corresponds to an Allan variance. Connecting all the different block times and the corresponding Allan variances will form the Allan standard curve.

[0152] (5) Calibration of the five random errors of the Allan variance

[0153] a. Quantization noise (its error coefficient Q)

[0154] Quantization noise is caused by the characteristics of the digital quantization coding sampling output of electronic instruments and reflects the minimum resolution. The angular power spectral density of quantization noise is:

[0155]

[0156] in ; Q is the quantization noise coefficient, and its theoretical value is , S is the scale factor.

[0157] The relationship between the rate power spectral density and the angle power spectral density of quantization noise is: , then the rate power spectral density of quantization noise is:

[0158]

[0159] in

[0160]

[0161] The extended line of the line segment with a slope of -1 on the double logarithmic curve of the Allan variance is The vertical coordinate reading of the intersection point is ;

[0162] b. Angle random walk (its error coefficient N)

[0163] Angle random walk is mainly caused by high-frequency noise with time correlation much shorter than the sampling time, and most of them can be eliminated. These noise terms all appear as white noise spectra in the rate output. The rate power spectral density of angle random walk can be expressed as:

[0164]

[0165] Where N is the angular random walk coefficient:

[0166]

[0167] The extended line of the line segment with a slope of -1 / 2 on the double logarithmic curve of the Allan variance is The vertical coordinate reading of the intersection point is ;

[0168] c. Bias instability (error coefficient B)

[0169] Bias instability is also known as Noise, meaning its power spectral density is inversely proportional to frequency. This noise is primarily caused by electronic devices. Since bias instability has low-frequency characteristics, it manifests as deviation fluctuations in the data. The rate power spectral density of bias instability is:

[0170]

[0171] Where: B is the zero-bias instability coefficient, is the cutoff frequency.

[0172]

[0173] The extension of the line segment with a slope of 0 on the double logarithmic curve of the Allan variance is The vertical coordinate reading of the intersection point is , usually take the minimum value of the bottom flat area or take or The value at;

[0174] d. Angular rate random walk (its error coefficient K)

[0175] The rate random walk is a random process of uncertain origin, which may be the limiting case of exponentially correlated noise with long correlation time. The rate power spectral density of the rate random walk is:

[0176]

[0177] Where K is the rate random walk coefficient.

[0178]

[0179] The extension of a line segment with a slope of 1 / 2 The vertical coordinate reading of the intersection point is

[0180] e. Angular rate slope (its error coefficient R)

[0181] The rate ramp is not random noise, but more like deterministic noise.

[0182]

[0183] Where R is the rate ramp coefficient.

[0184]

[0185] The rate power spectral density of the rate ramp is

[0186]

[0187] The extension of a line segment with a slope of 1 The vertical coordinate reading of the intersection point is ;

[0188] This embodiment assumes that the various error sources of the sea clutter test data are statistically independent, and the total Allan variance is the sum of the various error sources, that is, the square of the quantization noise , the square of the angular random walk , the square of the bias instability , the square of the angular rate random walk , the square of the angular rate slope The sum of .

[0189]

[0190] (6) Calculate cosine similarity

[0191] The cosine similarity test is used to test the similarity of the Allan variance diagrams of multiple data sets to characterize the stability of the sea clutter data.

[0192] Extract 30 data points at equal intervals from the Allan variance diagram of each group of data, and compare the vertical coordinates of any two groups of data points. Recorded as , calculate the cosine similarity :

[0193]

[0194] (7) Stability test

[0195] The total Allan variance and the five random errors obtained from each group of sea clutter data were statistically analyzed. , and the cosine similarity obtained from any two sets of data ,satisfy , then the sea clutter of the real sea surface is considered to be stable and effective, and any set of sea clutter echo data representing the target sea area can be selected from it.

[0196] The stability test method of the echo data of the sea clutter equivalent simulation board device is consistent with the above-mentioned test method of the stability of sea clutter on the real sea surface.

[0197] Step 4: Statistical analysis

[0198] From multiple sets of real sea clutter data and simulation board device echo data that have passed the stability test, one set is selected to represent the real sea clutter data and the simulated sea clutter data for statistical analysis.

[0199] Use Matlab to calculate the probability density PDF and cumulative probability density CDF of two sets of data, and obtain statistical data results and statistical curves;

[0200] Step 5: Goodness of fit test

[0201] By comparing the statistical result curves, we can intuitively find the consistency of the two sets of data results; and perform quantitative analysis on the obtained data to calculate the statistical goodness of fit S, S , indicating that the sea clutter equivalent simulation board works well;

[0202] Calculation method of statistical goodness of fit S: The statistics of real sea clutter echo data is ; The statistics of the equivalent analog board echo data are , respectively, normalize the two groups of data to obtain the data group and (N is the number of data statistic result points).

[0203] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0204] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0205] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0206] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific implementations of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating echoes of a sea clutter equivalent simulation board, characterized in that: The following steps are involved: Collecting and preprocessing real sea surface clutter echo data and equivalent simulation board sea clutter data to obtain preprocessed real sea surface clutter echo data and preprocessed equivalent simulation board sea clutter data; Performing effective data screening on the pre-processed real sea clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain effective data, wherein the effective data includes the real sea clutter echo effective data and the equivalent simulation board sea clutter effective data; Performing a stability test on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability test, and performing a stability test on valid data of sea clutter on an equivalent simulation board to obtain equivalent sea clutter data that passes the stability test; performing a stability test on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability test comprises the following steps: S11, dividing the sequence of valid data of the real sea surface clutter echo into a number of blocks according to the window length, each block including a number of data points, and there is no overlap between the blocks; S12, calculating the mean of several data points in each block and the overall mean of the effective data of the real sea surface clutter echo; S13, calculating the overall Allan variance using the means of several data points in each block; S14, changing the window length and repeating S11-S13, and drawing the Allan variance standard curve according to the relationship between the Allan variance and the bilateral power spectral density; S15, calculating the Allan variance random error, and calibrating the Allan variance random error on the Allan variance standard curve to obtain an Allan variance graph; S16, calculating the cosine similarity of the Allan variance graphs of any two sets of real sea clutter echo valid data; S17. Statistically analyzing the values ​​of the overall Allan variance and the random error of the Allan variance, if both are smaller than the overall mean of the valid data of the real sea surface clutter echoes, and the cosine similarity of the Allan variance graphs of any two groups of valid data of the real sea surface clutter echoes is greater than a first preset value, the real sea surface clutter echo data passes the stability test, and the real sea surface clutter echo data that passes the stability test is obtained; Selecting a set of real sea clutter representative data from the real sea surface clutter echo data that has passed the stability test, and selecting a set of simulated sea clutter representative data from the equivalent simulation board sea clutter data that has passed the stability test, performing statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtaining real sea clutter statistical data results, real sea clutter statistical curve graphs, simulated sea clutter statistical data results, and simulated sea clutter statistical curve graphs; The statistical curves of real sea clutter and simulated sea clutter are used for intuitive comparison, and the statistical goodness of fit between the statistical data of real sea clutter and the statistical data of simulated sea clutter is calculated to obtain the evaluation results.

2. The echo evaluation method of a sea clutter equivalent simulation board according to claim 1, characterized in that: The mean value of several data points in each block is calculated as follows: in, is the mean of several data points in each block, k is the block number, y is the sequence of valid data of real sea clutter echo, n is the number of data points in each block, and i is the number of data points; the mean value in each block is recorded as: , ...; The overall mean value of the effective data of the real sea clutter echo is calculated as follows: in, is the overall mean of the effective data of the real sea clutter echo, and m is the total number of data points of the effective data of the real sea clutter echo; The calculation of the overall Allan variance using the mean of several data points in each block is shown in the following formula: in, is the population Allan variance, is the mean of several data points in the k+1th block, is the mean of several data points in the kth block, is the total number of blocks.

3. The echo evaluation method of a sea clutter equivalent simulation board according to claim 1, characterized in that: The performing of stability test on the effective sea clutter data of the equivalent simulation board to obtain the equivalent sea clutter data that passes the stability test comprises the following steps: S21, dividing the sequence of effective sea clutter data of the equivalent simulation board into a number of blocks according to the window length, each block including a number of data points, and no overlap between blocks; S22, calculating the mean of several data points in each block and the overall mean of the effective sea clutter data of the equivalent simulation board; S23, calculating the overall Allan variance using the means of several data points in each block; S24, changing the window length and repeating S21-S23, and drawing the Allan variance standard curve using the relationship between the Allan variance and the bilateral power spectral density; S25, calculating the Allan variance random error, and calibrating the Allan variance random error on an Allan variance standard curve to obtain an Allan variance graph; S26, calculating the cosine similarity of the Allan variance diagrams of any two sets of equivalent simulation board sea clutter effective data; S27. Statistically analyze the values ​​of the overall Allan variance and the random error of the Allan variance. If both values ​​are smaller than the overall mean value of the effective sea clutter data of the equivalent simulation board, and the cosine similarity of the Allan variance graphs of any two groups of effective sea clutter data of the equivalent simulation board is greater than a second preset value, the equivalent simulation board sea clutter data passes the stability test, and equivalent simulation board sea clutter data that passes the stability test is obtained.

4. The echo evaluation method of a sea clutter equivalent simulation board according to claim 1 or 3, characterized in that: The Allan variance random error includes quantization noise, angle random walk, zero bias instability, angular rate random walk and angular rate slope; The total Allan error is the sum of the Allan variance and random error sources as shown below: in, is the total Allan error, is the square of the quantization noise, is the square of the random walk angle, is the square of the zero-bias instability, is the square of the random walk rate, is the square of the angular rate ramp; Q is the error coefficient of quantization noise, N is the error coefficient of angle random walk, B is the error coefficient of zero bias instability, K is the error coefficient of angular rate random walk, and R is the error coefficient of angular rate ramp.

5. The echo evaluation method of a sea clutter equivalent simulation board according to claim 1, characterized in that: The calculation of the statistical goodness of fit is as follows: Among them, S is the statistical goodness of fit, is the data set after statistical normalization of the actual sea clutter statistical data results, is the data set after statistical normalization of the statistical data results of simulated sea clutter, and N is the number of statistical data points; If the statistical goodness of fit is greater than 85%, the sea clutter equivalent simulation board is effective.

6. The echo evaluation method of a sea clutter equivalent simulation board according to claim 1, characterized in that: The preprocessing includes verification and correction, omission supplementation and data format unification. The effective data screening includes elimination of abnormal echo data, transmission pulse distance mismatch processing and IQ channel imbalance compensation processing. The abnormal echo data includes electromagnetic interference and data sampling saturation. The statistical analysis includes calculation of probability density and calculation of cumulative probability density.

7. A sea clutter equivalent simulation board echo evaluation system, using a sea clutter equivalent simulation board echo evaluation method according to any one of claims 1 to 6, characterized in that: include: A preprocessing data module is obtained, which is used to collect and preprocess the real sea surface clutter echo data and the equivalent simulation board sea clutter data to obtain the preprocessed real sea surface clutter echo data and the preprocessed equivalent simulation board sea clutter data; The effective data screening module is used to screen the pre-processed real sea surface clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain the real sea surface clutter echo effective data and the equivalent simulation board sea clutter effective data; a stability check module, configured to perform a stability check on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability check, and to perform a stability check on valid data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes the stability check, wherein the stability check adopts a stability check method combining Allan variance and cosine similarity algorithms; a statistical analysis module for selecting a group of real sea clutter representative data from the real sea clutter echo data that has passed the stability test, and selecting a group of simulated sea clutter representative data from the equivalent simulation board sea clutter data that has passed the stability test, performing statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtaining real sea clutter statistical data results, real sea clutter statistical curve graphs, simulated sea clutter statistical data results, and simulated sea clutter statistical curve graphs; The goodness of fit calculation module is used to make an intuitive comparison between the real sea clutter statistical curve and the simulated sea clutter statistical curve, and calculate the statistical goodness of fit between the real sea clutter statistical data results and the simulated sea clutter statistical data results to obtain the evaluation results.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for evaluating an echo of a sea clutter equivalent simulation board as claimed in any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the echo evaluation method of a sea clutter equivalent simulation board according to any one of claims 1 to 6.

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