Echo evaluation method and evaluation system for sea clutter equivalent simulation board

Abstract

The invention discloses an echo evaluation method and evaluation system for a sea clutter equivalent simulation board. The method comprises the following steps: collecting and preprocessing real sea surface clutter echo data and equivalent simulation board sea clutter data; effective data screening is carried out on the preprocessed real sea surface clutter echo data and the preprocessed equivalent simulation board sea clutter data; selecting a group of real sea clutter representative data from the real sea surface clutter echo data passing the stability test, selecting a group of simulated sea clutter representative data from the equivalent simulated board sea clutter data passing the stability test, and carrying out statistical analysis; and calculating the statistic fitting goodness of the real sea clutter statistical data result and the simulated sea clutter statistical data result to obtain an evaluation result. According to the invention, the echo simulation effect of the sea clutter equivalent simulation board device can be tested, the tested simulation board device is put into use, the cognition of sea clutter characteristics is deepened, the vacancy of actually measured data is made up, and the simulation of a real sea surface environment and the detection of a sea surface target are improved.

Description

Technical Field

[0001] The 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 the radio fuze detects and identifies targets at sea, the received echo signal contains not only the target information, but also the scattered echo of the sea background where the target is located - sea clutter. Sea clutter has a great influence on the target detection of the radio fuze. In order to improve the detection performance of the radio fuze to the target, it is necessary to analyze and study the characteristics of sea clutter in order to effectively suppress clutter interference.

[0003] The evaluation and analysis of the sea clutter equivalent simulation board is of great significance to the performance estimation of radio fuze, the design of radio fuze system, target detection and remote sensing. The statistical characteristics and spectral characteristics of sea clutter are more important. Usually, the probability density distribution function model describing the clutter backscatter coefficient is used to simulate the clutter, that is, the statistical model. In the realization of sea clutter simulation, the most important thing is to describe the mathematical model of the radio fuze environment. The modeling of the environment is often considered from the aspect of the amplitude probability density distribution function, that is, the radio fuze echo signal must conform to a certain amplitude probability distribution.

[0004] The sea clutter equivalent simulation board makes the sea clutter related tests more convenient by simulating the echo of sea clutter, but it is necessary to first evaluate the goodness of the simulated echo to ensure that the characteristics of the simulated echo are 85% equivalent to the echo characteristics of the real sea surface. Currently, there is little sea clutter test data, and the simulation of sea clutter mostly stays at the wave shape level. The simulation method of sea clutter echo is also mostly simple modeling simulation without physical simulation. Therefore, it is necessary to solve the problem that the existing technology cannot detect the echo simulation effect of the sea surface simulation device. 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 a sea surface simulation device, and proposes an echo evaluation method and an evaluation system for a sea clutter equivalent simulation board.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme: An echo evaluation method for a sea clutter equivalent simulation board comprises the following steps: 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; Perform stability test on effective data of real sea clutter echo to obtain real sea clutter echo data that passes stability test, perform stability test on effective data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes stability test; A group of real sea clutter representative data is selected from the real sea surface clutter echo data that have passed the stability test, and a group of simulated sea clutter representative data is selected from the equivalent simulation board sea clutter data that have passed the stability test, and statistical analysis is performed on the real sea clutter representative data and the simulated sea clutter representative data to obtain 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.

[0007] Furthermore, the performing of 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: S11, dividing the sequence of effective data of real sea surface clutter echoes 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 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 through the relationship between the Allan variance and the bilateral power spectral density; S15, calculating the random error of the Allen variance, and calibrating the random error of the Allen variance on the Allen variance standard curve to obtain an Allen variance graph; S16, calculating the cosine similarity of the Allan variance graphs of any two sets of effective data of real sea clutter echoes; S17. Count the values ​​of the overall Allan variance and the random error of the Allan variance respectively. If both are smaller than the overall mean value of the real sea surface clutter echo valid data, and the cosine similarity of the Allan variance graphs of any two groups of real sea surface clutter echo valid data is greater than a first preset value, then 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.

[0008] Furthermore, the mean value of several data points in each block is calculated as follows:

[0009] 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:

[0010] in, is the overall mean of the effective data of the real sea clutter echo, and m is the overall number of data points of the effective data of the real sea clutter echo; The overall Allan variance is calculated using the mean of several data points in each block as shown in the following formula:

[0011] in, is the overall 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.

[0012] Furthermore, the stability test of the effective sea clutter data of the equivalent simulation board is performed to obtain the equivalent sea clutter data that passes the stability test, which 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 there is no overlap between the blocks; S22, calculating the mean of several data points in each block and the overall mean of 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 through the relationship between the Allan variance and the bilateral power spectral density; S25, calculating the Allen variance random error, and calibrating the Allen variance random error on the Allen variance standard curve to obtain an Allen variance graph; S26, calculating the cosine similarity of the Allan variance graphs 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 respectively. If both are smaller than the overall mean of the effective data of the equivalent simulation plate sea clutter, and the cosine similarity of the Allan variance graphs of any two groups of effective data of the equivalent simulation plate sea clutter is greater than a second preset value, the equivalent simulation plate sea clutter data passes the stability test, and the equivalent simulation plate sea clutter data that passes the stability test is obtained.

[0013] Further, 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:

[0014] in, is the total Allan error, is the square of the quantization noise, is the square of the angle random walk, is the square of the zero-bias instability, is the square of the rate random walk, is the square of the angular rate slope; 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 slope.

[0015] Furthermore, the calculation of the statistical goodness of fit is as follows:

[0016] Among them, S is the statistical goodness of fit, is the data set after the statistical normalization of the actual sea clutter statistical data results. is the data set after the statistical normalization processing of the statistical data results of simulated sea clutter, and N is the number of statistical data result points; If the statistical goodness of fit is greater than 85%, the sea clutter equivalent simulation board has a good effect.

[0017] Furthermore, the preprocessing includes verification and correction, omission supplementation and unified data format, 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, and the statistical analysis includes calculation of probability density and calculation of cumulative probability density.

[0018] An echo evaluation system for a sea clutter equivalent simulation board, comprising: 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, and 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 clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain the real sea clutter echo effective data and the equivalent simulation board sea clutter effective data; A stability check module is used to perform stability check on effective data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability check, and to perform stability check on effective 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 Allen variance with cosine similarity algorithm; A statistical analysis module is used to select a group of real sea clutter representative data from the real sea surface clutter echo data that have passed the stability test, select a group of simulated sea clutter representative data from the equivalent simulation board sea clutter data that have passed the stability test, perform statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtain 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 module for calculating the goodness of fit is used to make an intuitive comparison using the real sea clutter statistical curve graph and the simulated sea clutter statistical curve graph, 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.

[0019] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the echo evaluation method of a sea clutter equivalent simulation board is implemented.

[0020] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the echo evaluation method of a sea clutter equivalent simulation board is implemented.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention proposes an echo evaluation method for a sea clutter equivalent simulation board. By studying the echo evaluation technology of the sea clutter equivalent simulation board, the stability and validity of the sea clutter test data are determined, the statistical characteristics of multiple groups of data are compared, and the simulation consistency is judged. The echo simulation effect of the sea clutter equivalent simulation board device can be tested. The simulation board device that has passed the test is put into use, which can deepen the understanding of the sea clutter characteristics, make up for the gaps in the measured data, improve the simulation of the real sea surface environment, detect sea surface targets, and optimize the performance of target detection and imaging algorithms. The sea clutter equivalent simulation board echo evaluation technology algorithm is simple, fast in calculation speed, and has strong universality. It can be promoted to detect the echo simulation effect of various sea surface simulation devices.

[0022] Furthermore, the stability of the sea clutter echo data measured multiple times is tested by combining the Allan variance and cosine similarity method. Furthermore, by comparing the statistical characteristic probability density and cumulative probability density of the two groups of data, a goodness of fit test is performed to achieve the purpose of testing the echo simulation effect of the sea clutter simulation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are for explanation 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 for illustration purposes 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: Figure 1 The present invention is a flow chart of an echo evaluation method of a sea clutter equivalent simulation board.

[0024] Figure 2 The present invention is a structural diagram of an echo evaluation system of a sea clutter equivalent simulation board.

[0025] Figure 3 The electronic device diagram of the echo evaluation method of the sea clutter equivalent simulation board of the present invention.

[0026] Figure 4 Schematic diagram of an echo evaluation method of a sea clutter equivalent simulation board in an embodiment of the present invention.

[0027] Figure 5 Schematic diagram of saturation abnormal data in an embodiment of the present invention.

[0028] Figure 6 Schematic diagram of Allan variance in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 described embodiments 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 creative work should fall within the scope of protection of the present invention.

[0030] Embodiment 1 See also Figure 1 , an echo evaluation method for a sea clutter equivalent simulation board comprises the following steps: 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; Perform stability test on effective data of real sea clutter echo to obtain real sea clutter echo data that passes stability test, perform stability test on effective data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes stability test; A group of real sea clutter representative data is selected from the real sea surface clutter echo data that have passed the stability test, and a group of simulated sea clutter representative data is selected from the equivalent simulation board sea clutter data that have passed the stability test, and statistical analysis is performed on the real sea clutter representative data and the simulated sea clutter representative data to obtain 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.

[0031] This embodiment collects and preprocesses real sea clutter echo data and sea clutter data of the equivalent simulation board, and performs effective data screening and stability test to ensure that the data used for evaluation is accurate and reliable, thereby improving the accuracy of the evaluation result. By using the real sea clutter statistical curve graph and the simulated sea clutter statistical curve graph for intuitive comparison, the differences and similarities between the two can be clearly seen. 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 results and the simulated sea clutter statistical data results, a quantitative evaluation result is obtained, which makes the evaluation process more objective and measurable, and helps to judge whether the effect of the sea clutter equivalent simulation board is good.

[0032] Performing stability test on valid data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability test includes the following steps: S11, dividing the sequence of effective data of real sea surface clutter echoes 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 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 through the relationship between the Allan variance and the bilateral power spectral density; S15, calculating the random error of the Allen variance, and calibrating the random error of the Allen variance on the Allen variance standard curve to obtain an Allen variance graph; S16, calculating the cosine similarity of the Allan variance graphs of any two sets of effective data of real sea clutter echoes; S17. Count the values ​​of the overall Allan variance and the random error of the Allan variance respectively. If both are smaller than the overall mean value of the real sea surface clutter echo valid data, and the cosine similarity of the Allan variance graphs of any two groups of real sea surface clutter echo valid data is greater than a first preset value, then 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.

[0033] The mean calculation of several data points in each block is as follows:

[0034] 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 real sea clutter echo is calculated as follows:

[0035] in, is the overall mean of the effective data of the real sea clutter echo, and m is the overall number of data points of the effective data of the real sea clutter echo; The overall Allan variance is calculated using the mean of several data points in each block as shown below:

[0036] in, is the overall 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.

[0037] Performing stability test on effective sea clutter data of equivalent simulation board to obtain sea clutter data of equivalent simulation board that passes stability test includes 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 there is no overlap between the blocks; S22, calculating the mean of several data points in each block and the overall mean of 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 through the relationship between the Allan variance and the bilateral power spectral density; S25, calculating the Allen variance random error, and calibrating the Allen variance random error on the Allen variance standard curve to obtain an Allen variance graph; S26, calculating the cosine similarity of the Allan variance graphs 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 respectively. If both are smaller than the overall mean of the effective data of the equivalent simulation plate sea clutter, and the cosine similarity of the Allan variance graphs of any two groups of effective data of the equivalent simulation plate sea clutter is greater than a second preset value, the equivalent simulation plate sea clutter data passes the stability test, and the equivalent simulation plate sea clutter data that passes the stability test is obtained.

[0038] Allan variance random errors include quantization noise, angle random walk, bias instability, angular rate random walk, and angular rate ramp; The total Allan error is the sum of the Allan variance and random error sources as shown below:

[0039] in, is the total Allan error, is the square of the quantization noise, is the square of the angle random walk, is the square of the zero-bias instability, is the square of the rate random walk, is the square of the angular rate slope; 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 slope.

[0040] The calculation of the goodness of fit statistic is as follows:

[0041] Among them, S is the statistical goodness of fit, is the data set after the statistical normalization of the actual sea clutter statistical data results. is the data set after the statistical normalization processing of the statistical data results of simulated sea clutter, and N is the number of statistical data result points; If the statistical goodness of fit is greater than 85%, the sea clutter equivalent simulation board has a good effect.

[0042] If the evaluation result shows that the statistical goodness of fit is lower than 85%, it means that the effect of the sea clutter equivalent simulation board is not good and needs to be optimized or improved. This provides an effective feedback mechanism, which helps to promote the continuous progress and improvement of the sea clutter equivalent simulation board technology. By accurately evaluating the effect of the sea clutter equivalent simulation board, 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.

[0043] 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.

[0044] Embodiment 2 See also Figure 2 , an echo evaluation system for a sea clutter equivalent simulation board, comprising: 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, and 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 clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain the real sea clutter echo effective data and the equivalent simulation board sea clutter effective data; A stability check module is used to perform stability check on effective data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability check, and to perform stability check on effective 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 Allen variance with cosine similarity algorithm; A statistical analysis module is used to select a group of real sea clutter representative data from the real sea surface clutter echo data that have passed the stability test, select a group of simulated sea clutter representative data from the equivalent simulation board sea clutter data that have passed the stability test, perform statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtain 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 module for calculating the goodness of fit is used to make an intuitive comparison using the real sea clutter statistical curve graph and the simulated sea clutter statistical curve graph, 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.

[0045] This embodiment realizes the automated process of the evaluation system from data preprocessing to the final evaluation results through modular design, improves the efficiency and accuracy of the evaluation, reduces the complexity and error rate of manual operation, and through the preprocessing data module and the effective data screening module, the system can ensure that the data used for evaluation is high-quality and effective, reduce the impact of noise and outliers on the evaluation results, and improve the reliability of the evaluation. The stability verification module evaluates the stability of the data more comprehensively, ensuring that the data used for statistical analysis is stable and reliable. The statistical analysis module generates a statistical curve chart, which provides rich information for the evaluation and understands the characteristics, differences and similarities of real sea clutter and simulated sea clutter. The module for calculating goodness of fit 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 judge whether the effect of the sea clutter equivalent simulation board is good, and provide a basis for subsequent optimization and improvement. The application of this evaluation system is helpful to promote the continuous progress and improvement of the technology of sea clutter equivalent simulation board. Through continuous evaluation and optimization, the performance of sea clutter equivalent simulation board can be improved, so that it can more accurately simulate the clutter characteristics of the real sea surface, and provide better support for the design and testing of radar systems.

[0046] Embodiment 3 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 a sea clutter equivalent simulation board described in Embodiment 1 is implemented.

[0047] Embodiment 4 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 described in the first embodiment is implemented.

[0048] Embodiment 5 A method for evaluating echoes of a sea clutter equivalent simulation board, the specific steps are as follows: The evaluation principle of this embodiment is to first study the scattering characteristics of the sea surface. The sea surface is a kind of random rough surface, and the research content of the electromagnetic scattering theory of random rough surfaces also includes the study of electromagnetic scattering of the sea surface. For a certain 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 a certain sea condition 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 change of the radio fuse echo of the sea surface scattering element within the coherence time must be considered, and the sea surface is accumulated and averaged over time.

[0049] 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, and 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 goodness of fit test is completed by comparing the calculation results.

[0050] Conduct multiple (3 or more) measurements in the target sea area on the same day through telemetry for at least three days 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 by telemetry; the measurement equipment, measurement method and measurement time of each set of data are consistent, and all data are recorded and saved.

[0051] Step 1: Data preprocessing.

[0052] The collected real sea surface clutter echo data and 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.

[0053] Step 2: Data screening The pre-processed data is screened to remove abnormal echo data such as electromagnetic interference, data sampling saturation, etc. Figure 5 As shown, the transmit pulse distance mismatch, IQ channel imbalance compensation, etc. are processed to ensure the validity of the data.

[0054] Step 3: Data stability test Sea surface fluctuations are mainly composed of gravity waves and capillary waves. The causes of sea clutter are complex and are affected by factors such as temperature, tides, and changes in the natural environment. In order to test whether the sea clutter data is stable under the influence of these factors and whether it can effectively represent the sea clutter characteristics of the real sea surface and the simulation board device, the present invention uses a method combining Allan variance and cosine similarity algorithm to perform the test.

[0055] The Allen variance method is a time domain analysis technique. By obtaining the difference sequence of two adjacent sets of data and finally obtaining the variance of all the differences, the Allen curve diagram is obtained to test the stability of the data or device. Compared with the classical variance, which can only analyze the error in general, the Allen variance can be used to analyze the mathematical characteristics of the potential random process that causes the error. This not only helps to identify the source of the known error terms in the observed data, but also helps to determine other internal sources of unknown errors. At the same time, the Allen variance removes short-term uncertainties by averaging within the block; and removes long-term uncertainties by taking differences between adjacent blocks. Therefore, this embodiment selects the Allen variance to test the stability of sea clutter data.

[0056] The specific method for stability testing of real sea clutter data includes the following steps: (1) Data segmentation By window length The processed sea clutter data sequence y is divided into Clusters, each containing n data points, with no overlap between clusters.

[0057] (2) Finding the average Calculate the mean of n data points in each block respectively, ; The mean value in each block is recorded as: , ,…… Find the overall mean of sea clutter data, a total of m points, ; (3) Calculate the Allan variance

[0058] Block Allan Variance :

[0059] Overall Allan variance:

[0060] (4) Draw the Allan variance standard curve The relationship between the Allan variance and the bilateral power spectral density is:

[0061] is the bilateral rate noise power spectral density, that is, the power spectral density of a stationary random process. For a non-stationary process, the time-averaged power spectral density needs to be used.

[0062] 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 present in the sea clutter data, which can then be used to The square root of the Allan variance The log-log double logarithmic curve plot was used for further analysis.

[0063] Changing block length , repeating the above steps (1) to (3), we can draw the double logarithmic curve of the Allan standard deviation versus block length, that is, the Allan variance curve, as shown in Figure 6 As shown in the figure, each time block corresponds to an Allen variance. Connecting all the different block times and the corresponding Allen variances will form the Allen standard curve.

[0064] (5) Calibration of the five random errors of the Allan variance a. Quantization noise (its error coefficient Q) Quantization noise is caused by the characteristics of the digital quantization encoding sampling output of electronic instruments, reflecting the minimum resolution. The angular power spectral density of quantization noise is:

[0065] in ; Q is the quantization noise coefficient, and its theoretical value is , S is the scale factor.

[0066] 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:

[0067] in

[0068]

[0069] The extended line of the line segment with a slope of -1 on the Allan variance double logarithmic curve is The vertical coordinate reading of the intersection point is ; b. Angle random walk (its error coefficient N) The 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 the angle random walk can be expressed as:

[0070] Where N is the angle random walk coefficient:

[0071] The extended line of the line segment with a slope of -1 / 2 on the Allan variance double logarithmic curve is The vertical coordinate reading of the intersection point is ; c. Bias instability (error coefficient B) Bias instability is also called Noise, that is, its power spectral density is inversely proportional to frequency. This noise is mainly caused by electronic devices. Since zero-bias instability has low-frequency characteristics, it manifests as deviation fluctuations in the data. The rate power spectral density of zero-bias instability is:

[0072] Where: B is the zero bias instability coefficient, is the cut-off frequency.

[0073]

[0074] The extended line of the line segment with a slope of 0 on the Allan variance double logarithmic curve is The vertical coordinate reading of the intersection point is , usually take the minimum value of the bottom flat area or or The value at; d. Angular rate random walk (its error coefficient K) 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:

[0075] Where K is the rate random walk coefficient.

[0076]

[0077] The extension of a line segment with a slope of 1 / 2 The vertical coordinate reading of the intersection point is

[0078] e. Angular rate slope (its error coefficient R) The rate ramp is not random noise, but more like deterministic noise.

[0079]

[0080] Where R is the rate ramp coefficient.

[0081]

[0082] The rate power spectral density of the rate ramp is

[0083] The extension of a line segment with a slope of 1 is The vertical coordinate reading of the intersection point is ; 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 angle random walk , the square of the zero bias instability , the square of the angular velocity random walk , the square of the angular rate slope The sum of .

[0084]

[0085] (6) Calculate cosine similarity

[0086] The cosine similarity was used to test the similarity of the Allan variance diagrams of multiple data sets and to characterize the stability of the sea clutter data.

[0087] Extract 30 data points at equal intervals from the Allen variance diagram of each group of data, and compare the ordinates of any two groups of data points Recorded as , calculate the cosine similarity :

[0088] (7) Stability test The total Allan variance and the values ​​of the five random errors obtained from each group of sea clutter data were statistically analyzed separately. , and the cosine similarity obtained from any two sets of data is ,satisfy , it is considered that the sea clutter on the real sea surface is stable and effective, and a set of sea clutter echo data representing the target sea area can be randomly selected.

[0089] 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 the sea clutter on the real sea surface.

[0090] Step 4: Statistical analysis From multiple groups of real sea clutter and simulated board device echo data that have passed the stability test, one group is selected to represent the real sea clutter and simulated sea clutter data for statistical analysis.

[0091] Calculate the probability density PDF and cumulative probability density CDF of two sets of data through Matlab, and get the statistical data results and statistical curve graphs; Step 5: Goodness of fit test 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; 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 sets of data to obtain the data set and (N is the number of data statistic result points).

[0092] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. 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 disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0093] 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 flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, 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 flowchart and / or block diagram. 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.

[0094] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0095] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions 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 solution of the present invention rather than to limit it. Although the present invention is described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation of the present invention can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not deviate from the spirit and scope of the present invention should be included in the protection scope 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; Perform stability test on effective data of real sea clutter echo to obtain real sea clutter echo data that passes stability test, perform stability test on effective data of equivalent simulation board sea clutter to obtain equivalent simulation board sea clutter data that passes stability test; A group of real sea clutter representative data is selected from the real sea surface clutter echo data that have passed the stability test, and a group of simulated sea clutter representative data is selected from the equivalent simulation board sea clutter data that have passed the stability test, and statistical analysis is performed on the real sea clutter representative data and the simulated sea clutter representative data to obtain 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 performing of stability test on the effective data of real sea clutter echo to obtain the real sea clutter echo data that passes the stability test comprises the following steps: S11, dividing the sequence of effective data of real sea surface clutter echo into a number of blocks according to the window length, each block includes 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 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 through the relationship between the Allan variance and the bilateral power spectral density; S15, calculating the random error of the Allen variance, and calibrating the random error of the Allen variance on the Allen variance standard curve to obtain an Allen variance graph; S16, calculating the cosine similarity of the Allan variance graphs of any two sets of effective data of real sea clutter echoes; S17. Count the values ​​of the overall Allan variance and the random error of the Allan variance respectively. If both are smaller than the overall mean value of the real sea surface clutter echo valid data, and the cosine similarity of the Allan variance graphs of any two groups of real sea surface clutter echo valid data is greater than a first preset value, then 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.

3. The echo evaluation method of a sea clutter equivalent simulation board according to claim 2, 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 overall number of data points of the effective data of the real sea clutter echo; The overall Allan variance is calculated using the mean of several data points in each block as shown in the following formula: in, is the overall 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.

4. 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 sea clutter data of the equivalent simulation board 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 there is no overlap between the blocks; S22, calculating the mean of several data points in each block and the overall mean of 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 through the relationship between the Allan variance and the bilateral power spectral density; S25, calculating the Allen variance random error, and calibrating the Allen variance random error on the Allen variance standard curve to obtain an Allen variance graph; S26, calculating the cosine similarity of the Allan variance graphs 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 respectively. If both are smaller than the overall mean of the effective data of the equivalent simulation plate sea clutter, and the cosine similarity of the Allan variance graphs of any two groups of effective data of the equivalent simulation plate sea clutter is greater than a second preset value, the equivalent simulation plate sea clutter data passes the stability test, and the equivalent simulation plate sea clutter data that passes the stability test is obtained.

5. The echo evaluation method of a sea clutter equivalent simulation board according to claim 2 or 4, 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 angle random walk, is the square of the zero-bias instability, is the square of the rate random walk, is the square of the angular rate slope; 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 slope.

6. The echo evaluation method of a sea clutter equivalent simulation board according to claim 1, characterized in that: The calculation of the goodness of fit statistic is as follows: Among them, S is the statistical goodness of fit, is the data set after the 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 result points; If the statistical goodness of fit is greater than 85%, the sea clutter equivalent simulation board has a good effect.

7. 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 unified data format, 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, and the statistical analysis includes calculation of probability density and calculation of cumulative probability density.

8. An echo evaluation system for a sea clutter equivalent simulation board, 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, and 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 clutter echo data and the pre-processed equivalent simulation board sea clutter data to obtain the real sea clutter echo effective data and the equivalent simulation board sea clutter effective data; A stability check module is used to perform stability check on effective data of real sea clutter echoes to obtain real sea clutter echo data that passes the stability check, and to perform stability check on effective 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 Allen variance with cosine similarity algorithm; A statistical analysis module is used to select a group of real sea clutter representative data from the real sea surface clutter echo data that have passed the stability test, select a group of simulated sea clutter representative data from the equivalent simulation board sea clutter data that have passed the stability test, perform statistical analysis on the real sea clutter representative data and the simulated sea clutter representative data, and obtain 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 module for calculating the goodness of fit is used to make an intuitive comparison using the real sea clutter statistical curve graph and the simulated sea clutter statistical curve graph, 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.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the echo evaluation method of a sea clutter equivalent simulation board as claimed in any one of claims 1 to 7 when executing the computer program.

10. 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 as claimed in any one of claims 1 to 7.

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