Distance extension target detection method and system based on correlation coefficient

Abstract

The invention discloses a distance extension target detection method based on a correlation coefficient. The method comprises the following steps: estimating the initial position and the number of continuous Doppler channels occupied by distance extension targets and the reference Doppler channel of the distance extension targets through preliminary calculation based on an echo distance Doppler spectrum; based on the reference Doppler channel signal sequence of the distance extension target, distance units of partial scattering points of the distance extension target and corresponding background clutter power estimation values are obtained through CA-CFAR detection; respectively constructing a scattering point distribution set and a background clutter power set of the distance expansion target based on the distance units of the partial scattering points and the corresponding background clutter power estimation values; based on the scattering point distribution set, the background clutter power set and the reference Doppler channel signal sequence, the initial position and the end position of the continuous distance unit occupied by the distance extension target are estimated through sliding window operation, and the number of the continuous distance unit occupied by the distance extension target is obtained based on the initial position and the end position.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar target detection, and in particular relates to a range-extended target detection method and system based on correlation coefficient. Background Art

[0002] Wideband high-resolution radars improve range resolution as bandwidth increases. The electromagnetic scattering echoes from targets with complex geometric structures (such as aircraft and ships) in the high-frequency region can be considered the superposition of multiple independent scattering center echoes. Due to the improved range resolution, the multiple scattering centers of the target are distributed radially within multiple range resolution bins, refining the signal from a point target into a range-extended target signal. Traditional detection methods fail to fully utilize the full target echo energy, resulting in reduced detection performance and, in turn, missed target detection or increased false alarm rates. Existing range-extended target CFAR detection methods based on window parameter estimation using the maximum generalized signal-to-noise ratio criterion perform a two-dimensional grid search using the range dimension data corresponding to each Doppler channel as the basic unit. The computational complexity of this criterion increases exponentially with the number of range bins, consuming significant computational resources. Furthermore, if multiple range-extended targets with varying signal-to-noise ratios exist within a Doppler channel, the maximum generalized signal-to-noise ratio criterion only outputs the starting position and number of consecutive range bins occupied by the range-extended target with the highest signal-to-noise ratio, resulting in missed detection of other targets with smaller signal-to-noise ratios. Summary of the Invention

[0003] To address these issues, the present invention proposes a method and system for detecting range-extended targets based on correlation coefficients. This method utilizes the strong correlation of range-extended target echoes in the Doppler dimension and a sliding window operation to effectively estimate the starting position and number of consecutive Doppler channels and range bins occupied by range-extended targets. Simulation results demonstrate that, compared with existing two-dimensional grid search methods based on the maximum generalized signal-to-noise ratio criterion, the proposed method avoids the problem of missed detection of targets with low signal-to-noise ratios, significantly reduces computational complexity, and improves the accuracy of estimating the number of consecutive range bins occupied by range-extended targets.

[0004] A first aspect of the present invention provides a method for detecting a range-extended target based on a correlation coefficient, comprising the following steps: estimating the starting position and number of continuous Doppler channels occupied by the range-extended target and the reference Doppler channel of the range-extended target through preliminary calculation based on the echo range Doppler spectrum; Acquire the range units and background clutter powers of the scattering points of the range extended target through CA-CFAR detection based on the reference Doppler channel of the range extended target, and construct the scattering point distribution set and the background clutter power set based on the range units and the background clutter powers, respectively; Based on the scattering point distribution set, the background clutter power set, and the reference Doppler channel signal sequence, a starting position and an ending position of consecutive range units occupied by the range-extended target are estimated through a left sliding window operation and a right sliding window operation, respectively, and the number of consecutive range units occupied by the range-extended target is obtained based on the starting position and the ending position.

[0005] Preferably, the step of estimating the starting position and number of continuous Doppler channels occupied by the range-extended target and the reference Doppler channel of the range-extended target by preliminary calculation based on the echo range Doppler spectrum further comprises: The correlation coefficient between adjacent Doppler channel signal sequences is obtained based on the echo range Doppler spectrum. The calculation expression is: Where c i represents the i-th Doppler channel of the RD spectrum, is the correlation coefficient between the i-th Doppler channel and the i+1-th Doppler channel, K is the number of distance sampling points, x i (˙) is the echo signal sequence of the i-th Doppler channel of the echo range Doppler spectrum, and L is the total number of Doppler channels; The correlation coefficient vector is obtained based on the correlation coefficient between adjacent Doppler channel signal sequences. The calculation expression is: In the formula is the preset correlation coefficient threshold, The correlation coefficient between adjacent Doppler channels is greater than The correlation coefficient vector of The specific logic of obtaining the starting position of the continuous Doppler channel occupied by the range-extended target based on the value in the correlation coefficient vector is as follows: based on the Doppler channel index values ​​corresponding to the elements in the correlation coefficient vector being multiple groups of continuous values, the starting position of the continuous Doppler channel occupied by the range-extended target is the minimum value of each group of continuous Doppler channel index values; obtaining a correlation coefficient between the starting Doppler channel and non-adjacent Doppler channels based on the echo range Doppler spectrum and the starting Doppler channel occupied by the range extended target, and further estimating the number of consecutive Doppler channels occupied by the range extended target; A reference Doppler channel of the range-extended target is acquired based on a starting position and a number of consecutive Doppler channels occupied by the range-extended target.

[0006] Preferably, the steps of acquiring the range units and background clutter powers of the scattering points of the range extended target through CA-CFAR detection based on the reference Doppler channel of the range extended target, and constructing the scattering point distribution set and the background clutter power set based on the range units and the background clutter powers, respectively, further include: Each distance unit of the reference Doppler channel is obtained as a unit to be detected. A preset number of protection units are respectively provided at both ends of the unit to be detected. A preset number of reference units are obtained based on the two ends of the protection units. The background clutter power Z of the unit to be detected is obtained based on the preset number of reference units. The calculation expression is: Where x i and y i They represent the reference unit samples at both ends of the unit to be detected, and n is the number of reference unit samples at either end of the unit to be detected; Construct the normalization factor, and the calculation expression is: Where P fa is the preset false alarm probability; Based on the background clutter power Z and the normalization factor T of the unit to be detected, an adaptive decision criterion is used to determine whether the unit to be detected is a target. The calculation expression is: Where D is the unit to be detected, TZ is the detection threshold, H1 represents the hypothesis that the target exists, and H0 represents the hypothesis that the target does not exist; Based on the unit to be detected where the target exists, the corresponding distance unit and background clutter power are obtained. The screening rule is: if the adaptive decision result of the unit to be detected is H1, the distance unit d of the unit to be detected is obtained. i and background clutter power Z i ; Based on the range unit and background clutter power, the scattering point distribution set and background clutter power set of the range extended target are obtained respectively, and the calculation expressions are: Where M represents the total number of scattering points detected.

[0007] Preferably, the step of estimating the starting position of the range-extended target occupying consecutive range units through a left sliding window operation based on the scattering point distribution set, the background clutter power set and the reference Doppler channel signal sequence further comprises: S310: Obtaining a true power value of each scattering point in the scattering point distribution set; S320: Based on the scatter point distribution, each distance unit x is concentrated i , take the true power value of the m range units on its left to construct the corresponding range window w L1 , based on the distance window w L1 Construct the test statistic and detection threshold, where the distance window w L1 The expression is: In the formula, m is a preset constant, p i is the true value of the power at the scattering point with extended range target; S330: Compare the test statistic with the detection threshold. If the test statistic is greater than the detection threshold, determine the distance window w. L1 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -m, the true value of the power p of the scattering point at the extended target i Update to the distance window w L1 The average power is obtained and the process jumps to S320 for loop iteration; otherwise, S340 is executed; S340: with p i-m Take the true power value of m distance units on the left of the starting point to construct the distance window w L2 , based on the distance window w L2 Construct the test statistic and detection threshold, where the distance window w L2 The expression is: S350: If the test statistic is greater than the detection threshold, determine the distance window w L1 and w L2 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -2m, the true value of the power p at the scattering point at the extended target i Update to the distance window w L2 The average power is obtained and the process jumps to S320 for loop iteration; otherwise, S360 is executed; S360: with p i-2m Take the true power value of the 2m distance unit on the left side of the starting point to construct the distance window w L3 , based on the distance window w L3 Construct the test statistic and detection threshold; the expression of the distance window is: ; S370: If the test statistic is greater than the detection threshold, determine the distance window w L1 、w L2 and wL3 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -4m, the true power value p of the scattering point at the extended target i Update to the distance window w L3 The average power of the range window w is determined and the process jumps to S320 for loop iteration; otherwise, the range window w is determined. L1 、w L2 and w L3 is background clutter, and the starting position of the range extension target occupying the continuous range unit is x i .

[0008] Preferably, the step of obtaining a correlation coefficient between the starting Doppler channel and non-adjacent Doppler channels based on the echo range Doppler spectrum and the starting Doppler channel occupied by the range extended target, and further estimating the number of consecutive Doppler channels occupied by the range extended target further comprises: Based on the echo range Doppler spectrum and the start Doppler channel occupied by the range extended target, the correlation coefficient between the start Doppler channel and the non-adjacent Doppler channels is calculated, and a correlation coefficient matrix is ​​constructed, which is expressed as follows: Where N is the correlation coefficient vector The number of elements in the , the subscript c of the correlation coefficient ρ j 、c j+1 、c j+2 、c j+3 、c j+4 represent the jth, j+1th, j+2th, j+3th, and j+4th Doppler channels respectively; The first-order difference Δr is calculated based on the correlation coefficient matrix, and the calculation expression is: Where r i (˙) is the correlation coefficient vector of the i-th row in the correlation coefficient matrix; The number of continuous Doppler channels occupied by the range-extended target is obtained based on the first-order difference matrix Δr, and the value is the maximum value index of each row of the first-order difference matrix.

[0009] Preferably, the step of acquiring the reference Doppler channel of the range-extended target based on the starting position and number of continuous Doppler channels occupied by the range-extended target further comprises: The calculation expression of the reference Doppler channel of the range extended target is: Where floor (˙) represents the rounding down operation, j represents the starting Doppler channel occupied by the range-extended target, and q represents the number of consecutive Doppler channels occupied by the range-extended target.

[0010] Preferably, the step of constructing a test statistic and a detection threshold based on the distance window further comprises: Calculate the average power decibel value in the distance window. The calculation expression is: In the formula, mean (˙) represents the mean operation, w L is the distance window; The detection threshold is constructed based on the average power decibel value of the distance window and the true power value of the scattering point, and its expression is: A test statistic is constructed based on the range window average power decibel value and the background clutter power set, and its expression is: Where Z i The background clutter power of the scattering point of the current range extension target.

[0011] A second aspect of the present invention provides a range-extended target detection system based on correlation coefficient, comprising: A data preprocessing module is used to estimate the starting position and number of continuous Doppler channels occupied by the range-extended target based on the echo range Doppler spectrum, and obtain the reference Doppler channel of the range-extended target; CA-CFAR detection module, used to obtain the scattering point distribution set and background clutter power set of the range-extended target; The range window parameter estimation module is used to estimate the starting position and number of continuous range cells occupied by the range extension target.

[0012] A third aspect of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor. When the computer program is executed by the processor, the method for detecting a distance-extended target based on a correlation coefficient as described in any one of the above items is implemented.

[0013] A fourth aspect of the present invention provides a computer-readable storage medium having instructions stored thereon, which, when executed by a processor, implement any of the above-mentioned methods for detecting range-extended targets based on correlation coefficients.

[0014] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: Based on the range Doppler spectrum of the echo signal, the starting position and number of the continuous Doppler channels occupied by the range-extended target are estimated, and the target reference Doppler channel is determined. The Doppler channel positions of all target objects are preliminarily determined. The starting position and number of the continuous range units occupied by the target are estimated only on the reference Doppler channel occupied by the target, which greatly reduces the amount of calculation.

[0015] The present invention obtains the potential distribution set of the target's partial scattering points in the range dimension by performing CA-CFAR detection based on the baseline Doppler channel of the range-extended target, thereby achieving preliminary acquisition of the scattering points of the range-extended target and effectively avoiding the problem of missed detection of targets with small signal-to-noise ratio caused by the window parameter estimation method based on the maximum generalized signal-to-noise ratio criterion.

[0016] Based on the target scattering point distribution set and the corresponding background noise power set, a sliding window operation is used to estimate the starting position and number of continuous distance units occupied by range-extended targets. Compared with the window parameter estimation method based on the maximum generalized signal-to-noise ratio criterion, the computational complexity is significantly reduced and the estimation accuracy of the number of continuous distance units occupied by range-extended targets is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein: Figure 1 Schematic diagram of a flow chart of a range-extended target detection method based on correlation coefficient in the present invention; Figure 2 Schematic diagram of an embodiment of S100 in a range-extended target detection method based on correlation coefficient in the present invention; Figure 3 Detection performance curve of a scene simulation experiment of a range-extended target detection method based on correlation coefficient in the present invention; Figure 4 This is a comparison result of the time consumption of the Monte-Carlo simulation experiment output algorithm of the range extension target detection method of the present invention and the window parameter estimation method based on the generalized maximum signal-to-noise ratio criterion; Figure 5 This is a comparison result of the estimation error of the number of distance units of the target object output by the range expansion target detection method of the present invention and the Monte-Carlo simulation experiment based on the generalized maximum signal-to-noise ratio criterion window parameter estimation method; Figure 6 These are one-dimensional range images of two ship targets with the same speed but different physical sizes and signal-to-noise ratios. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact ratios, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0019] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] First embodiment See also Figures 1 to 6 The first aspect of the present invention provides a method for detecting a range-extended target based on a correlation coefficient, comprising the following steps: S100: estimating the starting position and number of continuous Doppler channels occupied by the range-extended target and the reference Doppler channel of the range-extended target through preliminary calculation based on the echo range Doppler spectrum; S200: obtaining the range units and background clutter powers of the scattering points of the range-extended target through CA-CFAR detection based on the reference Doppler channel of the range-extended target, and constructing a scattering point distribution set and a background clutter power set based on the range units and the background clutter powers, respectively; S300: Estimate the starting position and ending position of the range-extended target occupying consecutive range units based on the scattering point distribution set, the background clutter power set, and the reference Doppler channel signal sequence through left sliding window operations and right sliding window operations, respectively, and obtain the number of consecutive range units occupied by the range-extended target based on the starting position and the ending position.

[0021] The estimation in steps S100 and S300 is a calculation term in this field. For specific calculation steps, please refer to the description of this embodiment.

[0022] The starting position and number of continuous Doppler channels occupied by the range-extended target and the reference Doppler channel of the range-extended target are estimated through preliminary calculation based on the echo range Doppler spectrum. The specific steps include: Calculate the correlation coefficient between adjacent Doppler channels of the range-Doppler spectrum. The expression is: Where c i represents the i-th Doppler channel of the RD spectrum, is the correlation coefficient between the i-th Doppler channel and the i+1-th Doppler channel, K is the number of distance sampling points, x i (˙) is the echo signal sequence of the i-th Doppler channel, is the total number of Doppler channels; The starting Doppler channel occupied by the range-extended target is estimated based on the correlation coefficient between adjacent Doppler channel signal sequences. The calculation expression is: In the formula is the preset correlation coefficient threshold. The strong correlation definition threshold is preset to 0.7, and may be other values ​​without limitation. The correlation coefficient between adjacent Doppler channels is greater than vector of Based on the echo range Doppler spectrum and the signal sequence of the range-extended target occupying the starting Doppler channel, the correlation coefficient between the starting Doppler channel and the non-adjacent Doppler channels is obtained, and the correlation coefficient matrix is ​​constructed, which is expressed as follows: Where N is the correlation coefficient vector The number of elements in the , the subscript c of the correlation coefficient ρ j 、c j+1 、c j+2 、c j+3 、c j+4 represent the jth, j+1th, j+2th, j+3th, and j+4th Doppler channels respectively; The first-order difference △r is calculated based on the correlation coefficient matrix. The calculation expression is: Where r i (˙) is the correlation coefficient vector of the i-th row in the correlation coefficient matrix; The number of continuous Doppler channels occupied by the range-extended target is obtained based on the first-order difference matrix △r, and the value is the maximum index of each row of the first-order difference matrix.

[0023] The calculation expression of the reference Doppler channel of the range extended target is: Where floor (˙) represents the rounding down operation, and j represents the starting Doppler channel occupied by the range-extended target.

[0024] This method uses Figure 2 Take this calculation process as an example: Each column in the figure represents a Doppler channel. Figure 2There are 6 target objects in the . Further, take target 3 as an example: it occupies the 9th to 11th Doppler channels and the 8th to 10th range units, then the starting Doppler channel of the target is the 9th, and the number of Doppler channels it occupies is 3, namely the 9th, 10th and 11th Doppler channels. The reference Doppler channel of target 3 is determined to be the 10th through the above method. In addition, due to Figure 2 Target 1 and target 2 occupy the same Doppler unit, and the total number of Doppler units occupied by all potential range-extended targets is 5.

[0025] CA-CFAR detection is performed on the reference Doppler channel of the range-extended target along the range dimension to obtain some scattering points of the range-extended target in the range dimension and the corresponding background clutter power estimates. The target scattering point distribution set and background clutter power set are constructed. The specific steps include: Each distance unit of the reference Doppler channel is taken as a unit to be detected. A preset number of protection units are respectively provided at both ends of the unit to be detected. A preset number of reference units are obtained based on the two ends of the protection units. The background clutter power Z of the unit to be detected is obtained based on the preset number of reference units. The expression is: Among them, x i and y i Represents the reference unit samples on both sides of the unit to be tested; Construct the normalization factor, which is expressed as: Where P fa is the preset false alarm probability; In this embodiment, 100 protection units are set on both sides of the unit sample to be detected, the reference window length 2n is 64, and the false alarm probability P fa Set to 10 -6 ; Based on the background clutter power Z of the unit to be detected and the normalization factor T, it is determined whether the unit sample to be detected is a target. The adaptive decision expression is: Where D is the unit sample to be detected, TZ is the detection threshold, H1 represents the hypothesis that the target exists, and H0 represents the hypothesis that the target does not exist; For each unit sample D to be detected that is greater than the detection threshold i , record the corresponding distance unit d at this time i and background clutter power Z i , construct the scattering point distribution set and background clutter power set under the range-extended target benchmark Doppler channel, and their expressions are: Where M represents the total number of detected target scattering points.

[0026] The starting position of the range-extended target occupying continuous range cells is estimated by a left sliding window operation based on the target scattering point distribution set, the background clutter power set, and the reference Doppler channel signal sequence. The specific steps are as follows: S310: Obtaining the true power value of each scattering point in the scattering point distribution set; S320: Based on the scatter point distribution, each distance unit x is concentrated i , take the true power value of the m range units on its left to construct the corresponding range window w L1 , based on the distance window w L1 Construct the test statistic and detection threshold, where the distance window w L1 The expression is: In the formula, m is a preset constant, p i is the true value of the power at the scattering point with extended range target; S330: Compare the test statistic and the detection threshold. If the test statistic is greater than the detection threshold, determine the distance window w. L1 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -m, the true value of the power p of the scattering point at the extended target i Update to the distance window w L1 The average power is obtained and the process jumps to S320 for loop iteration; otherwise, S340 is executed; S340: with p i-m Take the true power value of m distance units on the left of the starting point to construct the distance window w L2 , based on the distance window w L2 Construct the test statistic and detection threshold, where the distance window w L2 The expression is: S350: If the test statistic is greater than the detection threshold, determine the distance window w L1 and w L2 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -2m, the true value of the power p at the scattering point at the extended target i Update to the distance window w L2 The average power is obtained and the process jumps to S320 for loop iteration; otherwise, S360 is executed; S360: with p i-2m Take the true power value of the 2m distance unit on the left side of the starting point to construct the distance window w L3, based on the distance window w L3 Construct the test statistic and detection threshold; the expression of the distance window is: ; S370: If the test statistic is greater than the detection threshold, determine the distance window w L1 、w L2 and w L3 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -4m, the true power value p of the scattering point at the extended target i Update to the distance window w L3 The average power of the range window w is determined and the process jumps to S320 for loop iteration; otherwise, the range window w is determined. L1 、w L2 and w L3 is background clutter, and the starting position of the range extension target occupying the continuous range unit is x i .

[0027] The estimation of the end position of the distance extension target occupied by the continuous distance unit adopts the step logic of S310~S370 and adopts the right sliding window operation based on the distance window constructed in S310~S370, and estimates the number of continuous distance units occupied by the distance extension target based on the starting position and the end position.

[0028] In this embodiment, m is set to 5 based on the radar system resolution and detection scenario.

[0029] The simulation experiment of the above-mentioned distance extended target detection method based on correlation coefficient is carried out as follows: Set the simulation parameters as shown in the following table: First, a single-target simulation experiment was carried out. The target parameters are shown in Table 2 for target 1. The signal-to-noise ratio was set to 20 values ​​evenly distributed from -11dB to -7dB. 10 simulations were performed for each signal-to-noise ratio level. 5 The Monte-Carlo experiment was repeated independently, and the curve of target detection probability changing with signal-to-noise ratio was obtained as follows: Figure 3 See Figure 3 It can be obtained that when the target signal-to-noise ratio reaches -9.1dB, the detection probability can reach 87.7%.

[0030] To compare the time and error in estimating target range window parameters using the proposed method and a detection method based on the generalized maximum signal-to-noise ratio criterion, a multi-target simulation experiment was conducted. The parameters of six range-extended targets were set as shown in Table 2 above. 1000 independent Monte-Carlo simulations were repeated for each target. The target detection time and target length estimation error for the two different methods were calculated for each experiment. The average of the estimated errors from each experiment was used as the estimated error for the experiment. Figure 4 The time taken by the two methods for the first 100 Monte-Carlo experiments is shown. The horizontal axis represents the number of experiments and the vertical axis represents the time taken. After 1000 Monte-Carlo experiments, the average time taken by the method proposed in this invention is 0.0033s, while the average time taken by the generalized maximum signal-to-noise ratio criterion detection method to estimate the target parameters is 1.0112s. The processing efficiency of the distance expansion target detection method based on correlation coefficient proposed in this invention is better than that of the generalized maximum signal-to-noise ratio criterion detection method. At the same time, Figure 5 The estimation error histograms of the two methods, based on 1000 Monte-Carlo experiments, are presented. The horizontal axis represents the target length estimation error range, and the vertical axis represents the frequency of data within the estimation error range. Verified by 1000 Monte-Carlo experiments, the proposed method has an average estimation error of 3.971m, while the average estimation error of the generalized maximum signal-to-noise ratio (GSNR) criterion detection method is 6.7906m. The proposed method for distance-expanded target detection based on correlation coefficients outperforms the generalized maximum signal-to-noise ratio (GSNR) criterion in estimating the number of target distance units.

[0031] In order to illustrate the problem of missed detection of targets with small signal-to-noise ratios caused by the detection method based on the generalized maximum signal-to-noise ratio criterion, a dual-target simulation experiment was carried out. The radar bandwidth and sampling frequency were set to 15MHz, and only targets 2 and 4 were retained, with signal-to-noise ratios of 20 and 15dB respectively. The length of target 4 was set to 120m and the speed to 8m / s, while other parameters remained unchanged. The one-dimensional distance image of the two targets is as follows: Figure 6 As shown in Figure 4, the two targets occupy different continuous range units in the same Doppler channel. Simulation experiments were conducted using both the range-extended target detection method based on correlation coefficients and the detection method based on the generalized maximum signal-to-noise ratio criterion proposed in this patent. The detection results are shown in Table 4 below. The simulation results show that the method proposed in this patent can effectively avoid the problem of missed detection of targets with low signal-to-noise ratios caused by the detection method based on the generalized maximum signal-to-noise ratio criterion.

[0032] Based on simulation experiments, the proposed method for detecting extended-range targets based on correlation coefficients can effectively detect extended-range targets under certain signal-to-noise ratio conditions. Compared to detection methods based on the generalized maximum signal-to-noise ratio criterion, the proposed method offers higher estimation accuracy and faster processing speed, meeting the specific needs of real-time computing and providing strong support for efficient detection of extended-range targets.

[0033] Second embodiment A second aspect of the present invention provides a range-extended target detection system based on correlation coefficient, comprising: A data preprocessing module is used to estimate the starting position and number of continuous Doppler channels occupied by the range-extended target based on the echo range Doppler spectrum, and obtain the reference Doppler channel of the range-extended target; CA-CFAR detection module, used to obtain the scattering point distribution set and background clutter power set of the range-extended target; The range window parameter estimation module is used to estimate the starting position and number of continuous range cells occupied by the range extension target.

[0034] Third embodiment The third aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and runnable on the processor. When the computer program is executed by the processor, any one of the above-mentioned distance-extended target detection methods based on correlation coefficient is implemented.

[0035] Fourth embodiment A fourth aspect of the present invention provides a computer-readable storage medium having instructions stored thereon, which, when executed by a processor, implement any of the above-mentioned methods for detecting range-extended targets based on correlation coefficients.

[0036] In the description of this application, it should be noted that the terms "inner" and "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0037] It should also be noted that, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0038] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the identification content specifically executed by the above-described system and device can refer to the corresponding process in the aforementioned method embodiment.

[0039] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. A range-extended target detection method based on correlation coefficient, characterized in that: The steps include: estimating the starting position and number of continuous Doppler channels occupied by the range-extended target and the reference Doppler channel of the range-extended target through preliminary calculation based on the echo range Doppler spectrum; Acquire the range units and background clutter powers of the scattering points of the range extended target through CA-CFAR detection based on the reference Doppler channel of the range extended target, and construct the scattering point distribution set and the background clutter power set based on the range units and the background clutter powers, respectively; Based on the scattering point distribution set, the background clutter power set, and the reference Doppler channel signal sequence, a starting position and an ending position of consecutive range units occupied by the range-extended target are estimated through a left sliding window operation and a right sliding window operation, respectively, and the number of consecutive range units occupied by the range-extended target is obtained based on the starting position and the ending position.

2. The method for detecting extended range targets based on correlation coefficient according to claim 1, wherein: The step of estimating the starting position and number of continuous Doppler channels occupied by the range-extended target and the reference Doppler channel of the range-extended target by preliminary calculation based on the echo range Doppler spectrum further comprises: The correlation coefficient between adjacent Doppler channel signal sequences is obtained based on the echo range Doppler spectrum. The calculation expression is: Where c i represents the i-th Doppler channel of the RD spectrum, is the correlation coefficient between the i-th Doppler channel and the i+1-th Doppler channel, K is the number of distance sampling points, x i (˙) is the echo signal sequence of the i-th Doppler channel of the echo range Doppler spectrum, and L is the total number of Doppler channels; The correlation coefficient vector is obtained based on the correlation coefficient between adjacent Doppler channel signal sequences. The calculation expression is: In the formula is the preset correlation coefficient threshold, The correlation coefficient between adjacent Doppler channels is greater than The correlation coefficient vector of The specific logic of obtaining the starting position of the continuous Doppler channel occupied by the range-extended target based on the value in the correlation coefficient vector is as follows: based on the Doppler channel index values ​​corresponding to the elements in the correlation coefficient vector being multiple groups of continuous values, the starting position of the continuous Doppler channel occupied by the range-extended target is the minimum value of each group of continuous Doppler channel index values; obtaining a correlation coefficient between the starting Doppler channel and non-adjacent Doppler channels based on the echo range Doppler spectrum and the starting Doppler channel occupied by the range extended target, and further estimating the number of consecutive Doppler channels occupied by the range extended target; A reference Doppler channel of the range-extended target is acquired based on a starting position and a number of consecutive Doppler channels occupied by the range-extended target.

3. The method for detecting extended range targets based on correlation coefficient according to claim 1, wherein: The steps of acquiring the range units and background clutter powers of the scattering points of the range extended target through CA-CFAR detection based on the reference Doppler channel of the range extended target, and constructing the scattering point distribution set and the background clutter power set based on the range units and the background clutter powers respectively further include: Each distance unit of the reference Doppler channel is obtained as a unit to be detected. A preset number of protection units are respectively provided at both ends of the unit to be detected. A preset number of reference units are obtained based on the two ends of the protection units. The background clutter power Z of the unit to be detected is obtained based on the preset number of reference units. The calculation expression is: Where x i and y i They represent the reference unit samples at both ends of the unit to be detected, and n is the number of reference unit samples at either end of the unit to be detected; Construct the normalization factor, and the calculation expression is: Where P fa is the preset false alarm probability; Based on the background clutter power Z and the normalization factor T of the unit to be detected, an adaptive decision criterion is used to determine whether the unit to be detected is a target. The calculation expression is: Where D is the unit to be detected, TZ is the detection threshold, H1 represents the hypothesis that the target exists, and H0 represents the hypothesis that the target does not exist; Based on the unit to be detected where the target exists, the corresponding distance unit and background clutter power are obtained. The screening rule is: if the adaptive decision result of the unit to be detected is H1, the distance unit d of the unit to be detected is obtained. i and background clutter power Z i ; Based on the range unit and background clutter power, the scattering point distribution set and background clutter power set of the range extended target are obtained respectively, and the calculation expressions are: Where M represents the total number of scattering points detected.

4. The method for detecting extended range targets based on correlation coefficient according to claim 1, wherein: The step of estimating the starting position of the range-extended target occupying consecutive range units through a left sliding window operation based on the scattering point distribution set, the background clutter power set and the reference Doppler channel signal sequence further includes: S310: Obtaining a true power value of each scattering point in the scattering point distribution set; S320: Based on the scatter point distribution, each distance unit x is concentrated i , take the true power value of the m range units on its left to construct the corresponding range window w L1 , based on the distance window w L1 Construct the test statistic and detection threshold, where the distance window w L1 The expression is: In the formula, m is a preset constant, p i is the true value of the power at the scattering point with extended range target; S330: Compare the test statistic with the detection threshold. If the test statistic is greater than the detection threshold, determine the distance window w. L1 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -m, the true value of the power p of the scattering point at the extended target i Update to the distance window w L1 The average power is obtained and the process jumps to S320 for loop iteration; otherwise, S340 is executed; S340: with p i-m Take the true power value of m distance units on the left of the starting point to construct the distance window w L2 , based on the distance window w L2 Construct the test statistic and detection threshold, where the distance window w L2 The expression is: S350: If the test statistic is greater than the detection threshold, determine the distance window w L1 and w L2 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -2m, the true value of the power p at the scattering point at the extended target i Update to the distance window w L2 The average power is obtained and the process jumps to S320 for loop iteration; otherwise, S360 is executed; S360: with p i-2m Take the true power value of the 2m distance unit on the left side of the starting point to construct the distance window w L3 , based on the distance window w L3 Construct the test statistic and detection threshold; the expression of the distance window is: S370: If the test statistic is greater than the detection threshold, determine the distance window w L1 、w L2 and w L3 The starting position of the continuous distance unit occupied by the distance extension target is updated to x i -4m, the true power value p of the scattering point at the extended target i Update to the distance window w L3 The average power of the range window w is determined and the process jumps to S320 for loop iteration; otherwise, the range window w is determined. L1 、w L2 and w L3 is background clutter, and the starting position of the range extension target occupying the continuous range unit is x i .

5. The method for detecting extended range targets based on correlation coefficient according to claim 2, wherein: The step of obtaining a correlation coefficient between the starting Doppler channel and non-adjacent Doppler channels based on the echo range Doppler spectrum and the starting Doppler channel occupied by the range extended target, and further estimating the number of consecutive Doppler channels occupied by the range extended target further comprises: Based on the echo range Doppler spectrum and the range extended target occupying the starting Doppler channel, the correlation coefficient between the starting Doppler channel and the non-adjacent Doppler channels is calculated, and a correlation coefficient matrix is ​​constructed, which is expressed as follows: Where N is the correlation coefficient vector The number of elements in the , the subscript c of the correlation coefficient ρ j 、c j+1 、c j+2 、c j+3 、c j+4 represent the jth, j+1th, j+2th, j+3th, and j+4th Doppler channels respectively; The first-order difference Δr is calculated based on the correlation coefficient matrix, and the calculation expression is: Where r i (˙) is the correlation coefficient vector of the i-th row in the correlation coefficient matrix; The number of continuous Doppler channels occupied by the range-extended target is obtained based on the first-order difference matrix Δr, and the value is the maximum value index of each row of the first-order difference matrix.

6. The method for detecting extended range targets based on correlation coefficient according to claim 2, wherein: The step of acquiring a reference Doppler channel of the range-extended target based on the starting position and number of consecutive Doppler channels occupied by the range-extended target further comprises: The calculation expression of the reference Doppler channel of the range extended target is: Where floor (˙) represents the rounding down operation, j represents the starting Doppler channel occupied by the range-extended target, and q represents the number of consecutive Doppler channels occupied by the range-extended target.

7. The method for detecting extended range targets based on correlation coefficient according to claim 4, wherein: The step of constructing a test statistic and a detection threshold based on the range window further includes: Calculate the average power decibel value in the distance window. The calculation expression is: In the formula, mean (˙) represents the mean operation, w L is the distance window; The detection threshold is constructed based on the average power decibel value of the distance window and the true power value of the scattering point, and its expression is: A test statistic is constructed based on the range window average power decibel value and the background clutter power set, and its expression is: Where Z i The background clutter power of the scattering point of the current range extension target.

8. A range-extended target detection system based on correlation coefficient, characterized in that: include: A data preprocessing module is used to estimate the starting position and number of continuous Doppler channels occupied by the range-extended target based on the echo range Doppler spectrum, and obtain the reference Doppler channel of the range-extended target; CA-CFAR detection module, used to obtain the scattering point distribution set and background clutter power set of the range-extended target; The range window parameter estimation module is used to estimate the starting position and number of continuous range cells occupied by the range extension target.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the computer program is executed by a processor, the method for detecting range-extended targets based on correlation coefficients according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having instructions stored thereon, characterized in that: When the instructions are executed by the processor, a range-extended target detection method based on correlation coefficient is implemented as described in any one of claims 1 to 7.

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