CN112710997B - Radar maneuvering target detection method and system in scanning mode - Google Patents

Abstract

The invention relates to a method and a system for detecting a radar maneuvering target in a scanning mode. The method comprises the following steps: obtaining a distance-azimuth pulse two-dimensional echo of a maneuvering target in the current azimuth obtained in a radar scanning mode; performing FRFT operation on the pulse echo of each distance unit under the condition of FRFT conversion parameters to obtain detection statistics corresponding to each distance unit, detecting a maneuvering target in each distance unit according to the detection statistics, and outputting a first color group; carrying out non-coherent accumulation on the pulse echoes to obtain an amplitude average value, detecting the maneuvering target of the distance unit according to the amplitude average value, and outputting a second color group; superposing the first color group and the second color group to obtain the color display of the maneuvering target detection result; and updating the scanning direction of the antenna, and detecting the echo of the next scanning direction. The invention can realize the detection of the radar maneuvering target in the scanning mode and can distinguish different motion states of the moving target.

Description

A radar maneuvering target detection method and system in scanning mode

technical field

The invention relates to the field of radar signal processing, in particular to a method and system for detecting a radar maneuvering target in a scanning mode.

Background technique

As the main means of target detection, radar plays an important role in civil and military fields such as environmental monitoring and early warning detection. However, affected by the complex motion characteristics of the target and the complex background environment, the target echo shows low observable characteristics to varying degrees, which increases the difficulty of radar detection. Most of the radar working modes are divided into scanning mode and staring (resident) observation mode. The former radar antenna searches in space by means of mechanical scanning or point scanning. This mode has fewer target resident pulses and is usually used for warning or surveillance Radar; the latter beam points to a specific direction, can obtain a long-term residence, and has a large number of pulses available, and is usually used for further confirmation of the target and identification of the target. For staring (dwell) observations, although there are more pulses in a specific direction, the overall data volume is less because the radar does not scan. Therefore, how to realize the effective detection of maneuvering targets in scanning mode is a difficult problem in engineering applications.

At present, FRFT is widely used in staring observation radar, and the conditions are relatively mature, but there are always problems in the application of scanning mode radar, which are mainly reflected in the following two aspects: First, the algorithm has a large amount of calculation, and FRFT is a two-dimensional parameter search transformation , the transformation angle corresponds to the velocity change (acceleration) of the target, which can more accurately match the motion characteristics of the target. However, due to the need for two-dimensional transformation domain parameter search, compared with the traditional MTD one-dimensional Doppler domain search, the engineering cost is increased. Difficulty and calculation; second, since one transformation angle only corresponds to one value of acceleration, when performing a one-dimensional transformation domain search under a certain transformation angle condition, only the target of the acceleration is matched, making it easy to lose other maneuvers In addition, since coherent accumulation detects radial velocity, it is easy to miss a part of static (Doppler is zero), slow motion (Doppler overlaps with sea clutter) or tangential motion (Doppler is zero) target, resulting in missed detection.

Contents of the invention

The object of the present invention is to provide a radar maneuvering target detection method and system in scanning mode, so as to improve the maneuvering target detection performance.

To achieve the above object, the present invention provides the following scheme:

A radar maneuvering target detection method in scanning mode, comprising:

Obtain the range-azimuth pulse two-dimensional echo of the maneuvering target at the current azimuth obtained in the radar scanning mode;

Perform FRFT operation on the pulse echo of each range unit in the current azimuth under the condition of FRFT transformation parameters to obtain the detection statistic corresponding to each distance unit; the detection statistic corresponding to the i-th distance unit is the amplitude obtained by FRFT operation As a result, each range cell includes multiple pulse echoes, and the number of pulse echoes in each range cell is the same as the number of FRFT domain channels;

The maneuvering target in the distance unit is detected according to the detection statistic corresponding to each distance unit, and a first color group is output; the first color group includes the color corresponding to each distance unit;

Non-coherently accumulate the pulse echoes of each range unit in the current azimuth to obtain the average value of the amplitude;

According to the amplitude average value of each distance unit, the maneuvering target of the distance unit is detected, and the second color group is output; the second color group includes the color corresponding to each distance unit; the color in the second color group is the same as the colors in the first color set do not overlap;

superimposing the first color group and the second color group to obtain a color display of the detection result of the maneuvering target at the current orientation;

Update the scanning azimuth of the antenna, return to the step of "obtaining the range-azimuth pulse two-dimensional echo of the maneuvering target at the current azimuth obtained in the radar scanning mode", and detect the echo of the next scanning azimuth.

Optionally, the acquisition of the range-azimuth pulse two-dimensional echo of the current azimuth obtained in the radar scanning mode further includes:

A maneuvering target detection mode is obtained; the maneuvering target detection mode includes a manual detection mode and an automatic detection mode.

Optionally, in the manual detection mode, the pulse echo of each distance unit of the current orientation is subjected to FRFT operation under the condition of FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit, specifically including:

Perform FRFT operation on the pulse echo of each range unit in the current position under the current FRFT transformation parameter conditions to obtain the detection statistics corresponding to each range unit; the detection statistics corresponding to each range unit is a 1×N matrix; N is the number of pulse echoes in a range unit, and is also the number of channels in the FRFT domain.

Optionally, in the manual detection mode, the maneuvering target in the distance unit is detected according to the detection statistic corresponding to each distance unit, and the first color group is output, specifically including:

According to the detection statistics corresponding to all range cells, based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each range cell;

If there is a maneuvering target in the kth distance unit, output the first color at the corresponding position of the kth distance unit;

If there is no maneuvering target in the kth distance unit, the first color is not output at the corresponding position of the kth distance unit;

The color results output by the corresponding positions of each distance unit are sequentially obtained to obtain the first color group.

Optionally, in the automatic detection mode, the pulse echo of each distance unit of the current orientation is subjected to FRFT operation under the condition of FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit, specifically including:

Perform FRFT operation on the pulse echo of each range unit in the current orientation under the condition of multiple FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit; the detection statistics corresponding to each range unit is a matrix of N _p ×N ; N is the pulse echo quantity of one FRFT operation of a distance unit, and _Np is the number of FRFT transformation parameters, and different FRFT transformation parameters correspond to different motion states; motorized state.

Optionally, in the automatic detection mode, the maneuvering target in the distance unit is detected according to the detection statistic corresponding to each distance unit, and the first color group is output, specifically including:

For the kth distance unit, extract the maximum value of each column in the detection statistic matrix corresponding to the kth distance unit, and obtain the detection statistic after the dimensionality reduction of the kth distance unit; the kth The detection statistic after dimensionality reduction in the distance unit is a 1×N matrix, and the i-th element in the detection statistic matrix after dimensionality reduction is the maximum value of the amplitude in the i-th column of the detection statistic matrix before dimensionality reduction;

Obtain the detection statistics after dimensionality reduction for each distance unit in turn;

According to the detection statistics after dimensionality reduction of all distance units, based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each distance unit;

If there is a maneuvering target in the kth distance unit, according to the movement state of the maneuvering target, output the color corresponding to the movement state at the corresponding position of the kth distance unit; the colors corresponding to different movement states are different;

If there is no maneuvering target in the kth distance unit, no color is output at the corresponding position of the kth distance unit;

The color results output by the corresponding positions of each distance unit are sequentially obtained to obtain the first color group.

Optionally, in the manual detection mode, the superposition of the first color group and the second color group to obtain the color display of the maneuvering target detection result, and then further include:

Adjust the FRFT transformation parameters and return to the step of "performing FRFT operation on the pulse echo of each range unit under the condition of FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit" to detect targets with different maneuverability; different The FRFT transformation parameters correspond to target detections with different maneuverability, and the first color group of the target detection output with different maneuverability is different in depth.

Optionally, said detecting the maneuvering target in the distance unit according to the detection statistic corresponding to each distance unit, outputting the first color group, and then further including:

According to the first output color group, the initial velocity and acceleration of the maneuvering target are estimated in combination with FRFT transformation parameters and pulse echo parameters.

Optionally, the detection of the maneuvering target of the distance unit according to the average value of the amplitude of each distance unit is performed, and the second color group is output, which specifically includes:

According to the average value of the amplitude of all range cells, based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each range cell;

When there is a maneuvering target in the kth distance unit, output a second color at the position corresponding to the kth distance unit;

When there is no maneuvering target in the kth distance unit, the second color is not output at the position corresponding to the kth distance unit;

Obtain the second color output results corresponding to all the distance units in sequence to obtain the second color group.

The present invention also provides a radar maneuvering target detection system in scanning mode, comprising:

The echo acquisition module is used to acquire the range-azimuth pulse two-dimensional echo of the maneuvering target obtained under the radar scanning mode;

The FRFT operation module is used to perform FRFT operation on the pulse echo of each range unit in the current orientation under the condition of FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit; the detection statistics corresponding to the i-th distance unit are The amplitude result obtained by FRFT operation, each distance unit includes multiple pulse echoes, and the number of pulse echoes in each distance unit is the same as the number of channels in the FRFT domain;

The first color group output module is used to detect the maneuvering target in the distance unit according to the detection statistic corresponding to each distance unit, and output the first color group; the first color group includes the color corresponding to each distance unit;

The non-coherent accumulation module is used to non-coherently accumulate the pulse echoes of each range unit in the current azimuth to obtain the average value of the amplitude;

The second color output module is used to detect the maneuvering target of the distance unit according to the amplitude average value of each distance unit, and output the second color group; the second color group includes the color corresponding to each distance unit; the the colors in the second color set do not overlap the colors in the first color set;

The maneuvering target detection result color display module is used to superimpose the first color group and the second color group to obtain the color display of the maneuvering target detection result at the current position;

The updating module is used to update the scanning azimuth of the antenna, and return to the echo acquisition module to detect the echo of the next scanning azimuth.

According to the specific embodiments provided by the invention, the invention discloses the following technical effects:

The present invention utilizes the advantage that FRFT can effectively accumulate maneuvering targets, and effectively improves the detection performance of radar maneuvering targets; and only searches and detects at one or several transformation angles, which greatly reduces the amount of computation, and is suitable for scanning mode short pulse sequences moving target detection. At the same time, the present invention fuses and outputs FRFT coherent accumulation and traditional non-coherent interpulse accumulation processing results, which can simultaneously detect static, slow, tangentially moving, and maneuvering targets, reducing the probability of missed detection.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without paying creative labor.

Fig. 1 is a schematic flow chart of the radar maneuvering target detection method in the scanning mode of the present invention;

Fig. 2 is a schematic structural diagram of the radar maneuvering target detection system in the scanning mode of the present invention;

Fig. 3 is the schematic flow sheet of embodiment 1 of the present invention;

Fig. 4 is a schematic flow chart of Embodiment 2 of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

FIG. 1 is a schematic flowchart of a method for detecting a radar maneuvering target in a scanning mode according to the present invention. As shown in Figure 1, the radar maneuvering target detection method under the scanning mode of the present invention comprises the following steps:

Step 100: Obtain the range-azimuth pulse two-dimensional echo of the maneuvering target at the current orientation obtained in the radar scanning mode. The radar works in scanning mode, the antenna points to a direction each time, and then a series of distance units in the direction get the target detection result of the current direction, and then scans the next direction, and proceeds sequentially. Therefore, for the current azimuth, pulse compression processing is performed on the radar echo data in the range direction to obtain the radar echo data s _PC (t,t _m ) after range pulse compression:

In the formula, t is the fast time in the pulse, t _m is the slow time between pulses, R _s (t _m ) is the line-of-sight distance between the radar and the target, A _r is the echo amplitude, 2R _s (t _m )/c is the time delay , B is the transmitted signal bandwidth, c ₀ represents the speed of light, and λ is the signal wavelength. Assuming that the target is moving towards the radar, and only the radial velocity component is considered, the distance of the target is a polynomial function of time. Since the radar works in the scanning mode, the dwell time of the target beam is limited, and only the quadratic term can be used to represent the movement Target distance to walk.

In the formula, R _s (t _m ) represents the radial distance, r ₀ represents the initial distance; v ₀ and a _s are vectors, representing the initial velocity and acceleration of the target respectively, and storing the distance-azimuth pulse two-dimensional data matrix S _M×N = {s _PC (i,j)|i＝1,2,...,M; j＝1,2,...,N}, M is the number of range units, N is the number of pulse echoes in a range unit number.

Step 200: Perform FRFT operation on the pulse echo of each range unit in the current orientation under the condition of FRFT transformation parameters to obtain the detection statistics corresponding to each range unit. The invention includes two maneuvering target detection modes, which are manual detection mode and automatic detection mode. In the manual detection mode, the FRFT operation is performed on the pulse echoes of all distance units under the condition of one FRFT transformation parameter, and the detection statistics corresponding to each distance unit are obtained, and the detection statistics corresponding to each distance unit are 1×N matrix, the detection statistic of all distance units is a matrix of M×N, represented by D _M×N :

The rows in D _M×N represent the detection statistics of each range unit, and the columns represent the detection values of the same pulse-echo position in different distance units. N is the number of pulse echoes in a range unit, which is also the number of channels in the FRFT domain; M is the number of range units.

表示：In the automatic detection mode, FRFT operation is performed on the pulse echo of each distance unit in the current orientation under the condition of multiple FRFT transformation parameters, and the detection statistics corresponding to each distance unit are obtained. The detection statistic corresponding to each range unit is a matrix of N _p ×N, N is the number of pulse echoes in a range unit, N _p is the number of FRFT transformation parameters, different FRFT transformation parameters correspond to different motion states, motion The states include uniform motion state, motorized motion state and high motor motion state. For the i-th distance unit, the corresponding detection statistic is given by

express:

中行表示该距离单元在FRFT变换参数p₁下的检测统计量，列表示同一个脉冲回波位置载不同FRFT变换参数下的检测量。

The middle row represents the detection statistics of the distance unit under the FRFT transformation parameter p ₁ , and the column represents the detection quantity under different FRFT transformation parameters at the same pulse echo position.

Step 300: Detect the maneuvering target in the distance unit according to the detection statistic corresponding to each distance unit, and output the first color group. In the manual detection mode, it is directly based on the detection statistics corresponding to all distance units, and based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each distance unit. If there is a maneuvering target in the kth distance unit, output the first color at the corresponding position of the kth distance unit; if there is no maneuvering target in the kth distance unit, output the first color at the corresponding position of the kth distance unit The first color is not output; the color results output by the corresponding positions of each distance unit are sequentially obtained, and the first color group is obtained. Among them, the two-dimensional constant false alarm detection method is an existing mature technology.

中每一列的幅值最大值，得到所述第k个距离单元降维后的检测统计量：In the automatic detection mode, first, it is necessary to reduce the dimensionality of the detection statistics of each distance unit to obtain a 1×N matrix. For the kth distance unit, extract the detection statistic matrix corresponding to the kth distance unit

The maximum value of the amplitude of each column in , to obtain the detection statistic after dimensionality reduction of the kth distance unit:

表示距离r_k处的

中第j个列向量中幅值最大值对应的变换参数。第k个距离单元降维后的检测统计量为1×N的矩阵，降维后的检测统计量矩阵中第j个元素为降维前检测统计量矩阵中第j列中的幅值最大值。In the formula,

represents the distance r _k

The transformation parameter corresponding to the maximum value in the jth column vector in . The detection statistic after dimensionality reduction of the k-th distance unit is a 1×N matrix, and the jth element in the detection statistic matrix after dimensionality reduction is the maximum value of the amplitude in the jth column of the detection statistic matrix before dimensionality reduction .

The detection statistics after dimension reduction of each distance unit are obtained in turn, and the detection statistics C _M×N of all distance units after dimension reduction are obtained:

Then, according to the dimensionality-reduced detection statistics C _M×N of all distance units, it is judged whether there is a maneuvering target in each distance unit based on the two-dimensional constant false alarm detection method. If there is a maneuvering target in the k-th distance unit, according to the motion state of the maneuvering target, output the color corresponding to the motion state at the corresponding position of the k-th distance unit, and the colors corresponding to different motion states are different; if the k-th When there is no maneuvering target in the kth distance unit, no color is output at the position corresponding to the kth distance unit. The color results output by the corresponding positions of each distance unit are sequentially obtained to obtain the first color group.

After the first color group is output, the initial velocity and acceleration of the maneuvering target can be estimated according to the output first color group in both manual detection mode and automatic detection mode, combined with FRFT transformation parameters and pulse echo parameters.

Step 400: Perform non-coherent accumulation on the pulse echoes of each range unit in the current azimuth to obtain the average value of the amplitude. When performing non-coherent accumulation, the pulse echoes of each distance unit can be sequentially averaged to obtain the average value of the amplitude, and the average value of the amplitude at this time is the average value of the value. Alternatively, the amplitude weighted average of the pulse echoes of each distance unit is sequentially obtained to obtain the average value of the amplitude, and at this time, the average value of the corresponding amplitude of each unit is the weighted average value.

Step 500: Detect the maneuvering target in the range unit according to the average value of the amplitude of each range unit, and output the second color group. The specific process is as follows:

judging whether the average value of the amplitude corresponding to each distance unit is greater than the second threshold;

When the average amplitude value corresponding to the kth distance unit is greater than the second threshold, it is determined that there is a maneuvering target in the kth distance unit, and a second color is output at the position corresponding to the kth distance unit;

When the average amplitude value corresponding to the kth distance unit is not greater than the second threshold, it is determined that there is no maneuvering target in the kth distance unit, and the second color is not output at the position corresponding to the kth distance unit;

The output results of the second color corresponding to all the distance units are obtained sequentially, and the second color group is obtained.

Step 600: Superimpose the first color group and the second color group to obtain the color display of the detection result of the maneuvering target at the current position.

In the manual detection mode, after obtaining the detection results corresponding to the current FRFT transformation parameters, by adjusting the FRFT transformation parameters and re-executing steps 200 to 600, the detection results of targets with different maneuverability can be further obtained, and the detection output of targets with different maneuverability The first color group differs in shades. The larger the FRFT transformation parameter is, the darker the color of the first color group is, and the stronger the maneuverability of the corresponding target is.

Step 700: Update the scanning orientation of the antenna. Returning to step 100, the echoes of the next scanning azimuth are detected until all azimuths are scanned, and the target detection results of all azimuths are obtained.

Based on the above method, the present invention also provides a radar maneuvering target detection system in scanning mode. FIG. 2 is a schematic structural diagram of the radar maneuvering target detection system in scanning mode of the present invention. As shown in Figure 2, the radar maneuvering target detection system in the scanning mode of the present invention includes:

The echo acquisition module 201 is configured to acquire the range-azimuth pulse two-dimensional echo of the maneuvering target at the current orientation obtained in the radar scanning mode.

The FRFT operation module 202 is used to perform FRFT operation on the pulse echo of each range unit of the current orientation under the FRFT transformation parameter condition, to obtain the detection statistic corresponding to each distance unit; the detection statistic corresponding to the i-th distance unit is For the amplitude result obtained by FRFT operation, each distance unit includes multiple pulse echoes, and the number of pulse echoes in each distance unit is the same as the number of channels in the FRFT domain.

The first color group output module 203 is used to detect the maneuvering target in the distance unit according to the detection statistic corresponding to each distance unit, and output the first color group; the first color group includes the color corresponding to each distance unit .

The non-coherent accumulation module 204 is configured to perform non-coherent accumulation on the pulse echoes of each range unit in the current azimuth to obtain the average value of the amplitude.

The second color output module 205 is used to detect the maneuvering target of the distance unit according to the average value of each distance unit, and output the second color group; the second color group includes the color corresponding to each distance unit; The colors in the second color group do not overlap with the colors in the first color group.

The maneuvering target detection result color display module 206 is configured to superimpose the first color group and the second color group to obtain the color display of the maneuvering target detection result at the current position;

The updating module 207 is configured to update the scanning azimuth of the antenna, return to the echo acquisition module, and detect the echo of the next scanning azimuth.

The above solutions of the present invention will be further described below in conjunction with specific examples.

Specific embodiment 1

In this embodiment, manual detection mode is adopted, and FIG. 3 is a schematic flow chart of Embodiment 1 of the present invention. As shown in Figure 3, the detection process includes two branches:

The first branch is the FRFT coherent accumulation branch. The FRFT transformation parameters and the number of accumulated pulses are set. According to the motion characteristics of the target to be detected, the FRFT operation is performed on the pulses in different distance units under the condition of specific transformation parameters. The results are consistent with the first A threshold is compared, repeated until the end of the radar scan, and output the maneuvering target detection result.

其距离为r_i，i＝1,2,...,M，采用线性调频信号(LinearFrequency Modulated,LFM)作为近似For scanning mode radars, the dwell time of the target is short, and the echo of the maneuvering target at a certain range cell

The distance is r _i , i=1,2,...,M, using linear frequency modulated signal (Linear Frequency Modulated, LFM) as an approximation

表示距离为r_i处的回波幅度，由距离为r_i处的信号初速度

产生的初始频率

由距离为r_i处的信号加速度

产生的调频率

该回波信号的FRFT表示为In the formula,

Indicates the echo amplitude at the distance r _i , from the signal initial velocity at the distance r _i

The initial frequency generated

By the signal acceleration at distance r _i

FM frequency generated

The FRFT of the echo signal is expressed as

where p is the transformation parameter, p∈(-2,2], F _p is the FRFT operator, T _n is the coherent accumulation time, for scanning radar, T _n is the dwell time of a beam, K _p ( t _m ,u) represents the FRFT kernel function,

是旋转角度；In the formula, A _p is a coefficient, n is an integer,

is the rotation angle;

Carry out FRFT operation under the condition of p _i for N pulse echoes in a certain distance unit, N represents the total number of azimuth pulses within a beam range, and its duration is not greater than T _n , according to the motion characteristics of the target to be detected, the different distance units The pulses in are subjected to FRFT operation under the condition of specific transformation parameters p _i , p _i is given according to the following relationship:

的关系为

式中，

为量纲归一化后的调频率，

fs为采样频率；由于

的取值范围为(0,π)，因此，p在量纲归一化后的取值范围为(0,2)，又由于p的对称性，因此p取值范围为[1,2)，则p的数值范围为[1,p₁,p₂,...,p_i,...,2)，p的取值越大，对应调频率越高，代表目标机动性越强，人工模式下可以根据需求调节FRFT变换参数的取值；Transformation parameter p and tuning frequency

The relationship is

In the formula,

is the tuning frequency after dimension normalization,

fs is the sampling frequency; because

The value range of p is (0,π), therefore, the value range of p after dimension normalization is (0,2), and because of the symmetry of p, the value range of p is [1,2) , then the value range of p is [1,p ₁ ,p ₂ ,..., _pi ,...,2), the larger the value of p, the higher the corresponding tuning frequency, which means the stronger the maneuverability of the target. In the manual mode, the value of the FRFT transformation parameters can be adjusted according to the demand;

Perform FRFT operation on the pulses in different distance units in turn under the condition of specific transformation parameters p _i , and form the detection statistic D _M×N with its amplitude:

表示距离r_i处(即距离单元r_i)回波变换参数p_i的FRFT域，将D_M×N中每一个元素与门限进行比较，如果幅值低于检测门限，判决为该距离单元没有机动目标，若幅值高于检测门限，则判决为该距离单元存在机动目标。In the formula,

Represents the FRFT domain of the echo transformation parameter p _i at the distance r _i (that is, the distance unit r _i ), compares each element in D _M×N with the threshold, if the amplitude is lower than the detection threshold, it is judged that the distance unit has no For a maneuvering target, if the amplitude is higher than the detection threshold, it is judged that there is a maneuvering target in this distance unit.

The second branch is a non-coherent accumulation branch, which is the same as the number of accumulated pulses in the first branch. The pulse amplitude in each distance unit is averaged in turn, and the average value of the amplitude is compared with the second threshold. Repeat until the end of the radar scan, and output the target detection result, which is displayed in color B.

The results of the first branch and the second branch are superimposed and displayed to be the final detection result.

Manually adjust the transformation parameters p _i , and represent the detection results under different transformation parameters with color A. The color depth corresponds to the transformation parameters. The darker the color, the larger the transformation parameters, and the stronger the mobility of the target. Finally, the target detection results under different maneuverability can be obtained.

则目标的初速度估计值

和加速度估计值

为：Finally, the motion parameters of the target can be estimated. The transformation parameters corresponding to the peak value passing the detection threshold and the peak coordinates of the optimal transformation domain are

Then the estimated initial velocity of the target

and acceleration estimates

for:

Specific embodiment 2

In this embodiment, the automatic detection mode is adopted, and FIG. 4 is a schematic flow chart of Embodiment 2 of the present invention. As shown in Figure 4, in the automatic detection mode, the first branch is the FRFT coherent accumulation branch, and a certain number of FRFT transformation parameters are set to correspond to the motion states of uniform motion, maneuvering, and high maneuvering, respectively. Perform FRFT operation on the pulses in multiple transformation parameters, compare the result with the threshold, repeat until the end of the radar scan, output the maneuvering target detection result, and display it in color C\D\E..., the number and the number of transformation parameters The same; the process of the second branch is the same as that of the second branch in the manual detection mode, and it is displayed in color B; the results of the first branch and the second branch are superimposed and displayed.

In this embodiment, the FRFT transformation parameter setting method is as follows: p ₁ =1, corresponding to a uniform moving target; p ₂ =1+Δp', corresponding to a maneuvering target; p ₃ =1+2Δp', corresponding to a high maneuvering target; p _i =1+(i-1)Δp', the number of transformation parameters p _i is N _p , N _p and the interval Δp' are adjusted according to the resources of the radar system, and generally no more than five for scanning radars.

The FRFT operation method under the condition of multiple transformation parameters is as follows: firstly, the FRFT operation under the condition of N _p transformation parameters is performed in each distance unit, and the matrix at the distance r _i is obtained

Dimensionality reduction is performed on the operation results of each distance unit, and the maximum value of the column vector amplitude is taken to obtain the FRFT amplitude of the best transformation parameters of different FRFT domain channels

表示距离r_i处的

中第j个列向量幅值最大值对应的变换参数；In the formula,

represents the distance r _i

The transformation parameter corresponding to the maximum value of the jth column vector amplitude in ;

Carry out FRFT calculations under multiple transformation parameter conditions on the pulses in different distance units in turn to form a detection statistic C _M×N ,

Compare C _M×N with the threshold, if the amplitude is lower than the detection threshold, it is judged that there is no maneuvering target in this range unit, if the amplitude is higher than the detection threshold, it is judged that there is a maneuvering target in this range unit; repeat until the radar scans End, output the detection result of the maneuvering target, and display it in color C\D\E..., the number is the same as the number of transformation parameters, and different colors represent different motion states.

则目标的初速度估计值

和加速度估计值

为：Finally, the motion parameters of the target can be estimated. The transformation parameters corresponding to the peak value passing the detection threshold and the peak coordinates of the optimal transformation domain are

Then the estimated initial velocity of the target

and acceleration estimates

for:

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. As for the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, there will be changes in specific implementation methods and application ranges. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (9)

1. A radar maneuvering target detection method under scanning mode, is characterized in that, comprising: Obtain the range-azimuth pulse two-dimensional echo of the maneuvering target at the current azimuth obtained in the radar scanning mode; Perform FRFT operation on the pulse echo of each range unit in the current azimuth under the condition of FRFT transformation parameters to obtain the detection statistic corresponding to each distance unit; the detection statistic corresponding to the i-th distance unit is the amplitude obtained by FRFT operation As a result, each range cell includes multiple pulse echoes, and the number of pulse echoes in each range cell is the same as the number of FRFT domain channels; The maneuvering target in the distance unit is detected according to the detection statistic corresponding to each distance unit, and a first color group is output; the first color group includes the color corresponding to each distance unit; Non-coherently accumulate the pulse echoes of each range unit in the current azimuth to obtain the average value of the amplitude; According to the amplitude average value of each distance unit, the maneuvering target of the distance unit is detected, and the second color group is output; the second color group includes the color corresponding to each distance unit; the color in the second color group is the same as the colors in the first color set do not overlap; Said detecting the maneuvering target of the distance unit according to the average value of the amplitude of each distance unit, and outputting the second color group specifically includes: According to the average value of the amplitude of all range cells, based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each range cell; When there is a maneuvering target in the kth distance unit, output a second color at the position corresponding to the kth distance unit; When there is no maneuvering target in the kth distance unit, the second color is not output at the position corresponding to the kth distance unit; Obtain the second color output results corresponding to all the distance units in sequence to obtain the second color group; superimposing the first color group and the second color group to obtain a color display of the detection result of the maneuvering target at the current orientation; Update the scanning azimuth of the antenna, return to the step of "obtaining the range-azimuth pulse two-dimensional echo of the maneuvering target at the current azimuth obtained in the radar scanning mode", and detect the echo of the next scanning azimuth. 2. radar maneuvering target detection method under the scanning mode according to claim 1, is characterized in that, the range-bearing pulse two-dimensional echo of the current bearing obtained under the described acquisition radar scanning mode, also comprises afterwards: A maneuvering target detection mode is obtained; the maneuvering target detection mode includes a manual detection mode and an automatic detection mode. 3. radar maneuvering target detection method under scanning mode according to claim 2, it is characterized in that, under manual detection mode, described pulse echo of each range unit to current bearing carries out FRFT operation under FRFT transformation parameter condition , to obtain the detection statistics corresponding to each distance unit, including: Perform FRFT operation on the pulse echo of each range unit in the current orientation under the current FRFT transformation parameter conditions to obtain the detection statistics corresponding to each distance unit; the detection statistics corresponding to each range unit is a matrix of 1×N; N is the number of pulse echoes in one range unit. 4. radar maneuvering target detection method under scanning mode according to claim 3 is characterized in that, under manual detection mode, according to the detection statistic corresponding to each distance unit, the maneuvering target in the distance unit is detected, output the first A color group, specifically including: According to the detection statistics corresponding to all range cells, based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each range cell; If there is a maneuvering target in the kth distance unit, output the first color at the corresponding position of the kth distance unit; If there is no maneuvering target in the kth distance unit, the first color is not output at the corresponding position of the kth distance unit; The color results output by the corresponding positions of each distance unit are sequentially obtained to obtain the first color group. 5. radar maneuvering target detection method under scanning mode according to claim 2, it is characterized in that, under automatic detection mode, described to the pulse echo of each distance unit of current bearing carries out FRFT operation under FRFT transformation parameter condition , to obtain the detection statistics corresponding to each distance unit, including: Perform FRFT operation on the pulse echo of each range unit in the current orientation under the condition of multiple FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit; the detection statistics corresponding to each range unit is a matrix of N _p ×N ; N is the number of pulse echoes in a distance unit, and _Np is the number of FRFT transformation parameters, and different FRFT transformation parameters correspond to different motion states; the motion state includes a uniform motion state, a maneuvering motion state and a high maneuvering motion state . 6. the radar maneuvering target detection method under the scan mode according to claim 5 is characterized in that, under the automatic detection mode, according to the detection statistic corresponding to each distance unit, the maneuvering target in the distance unit is detected, and the output first A color group, specifically including: For the kth distance unit, extract the maximum value of each column in the detection statistic matrix corresponding to the kth distance unit, and obtain the detection statistic after the dimensionality reduction of the kth distance unit; the kth The detection statistic after dimensionality reduction in the distance unit is a 1×N matrix, and the i-th element in the detection statistic matrix after dimensionality reduction is the maximum value of the amplitude in the i-th column of the detection statistic matrix before dimensionality reduction; Obtain the detection statistics after dimensionality reduction for each distance unit in turn; According to the detection statistics after dimensionality reduction of all distance units, based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each distance unit; If there is a maneuvering target in the kth distance unit, according to the movement state of the maneuvering target, output the color corresponding to the movement state at the corresponding position of the kth distance unit; the colors corresponding to different movement states are different; If there is no maneuvering target in the kth distance unit, no color is output at the corresponding position of the kth distance unit; The color results output by the corresponding positions of each distance unit are sequentially obtained to obtain the first color group. 7. The radar maneuvering target detection method under the scanning mode according to claim 3, characterized in that, in the manual detection mode, the first color group and the second color group are superimposed to obtain maneuvering target detection The color display of the result, after which also includes: Adjust the FRFT transformation parameters and return to the step of "performing FRFT operation on the pulse echo of each range unit under the condition of FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit" to detect targets with different maneuverability; different The FRFT transformation parameters correspond to target detections with different maneuverability, and the first color group of the target detection output with different maneuverability is different in depth. 8. The radar maneuvering target detection method under the scanning mode according to claim 1, wherein the maneuvering target in the distance unit is detected according to the detection statistic corresponding to each distance unit, and the first color group is output, Then also include: According to the first output color group, the initial velocity and acceleration of the maneuvering target are estimated in combination with FRFT transformation parameters and pulse echo parameters. 9. A radar maneuvering target detection system in scanning mode, characterized in that it comprises: The echo acquisition module is used to acquire the range-azimuth pulse two-dimensional echo of the maneuvering target obtained under the radar scanning mode; The FRFT operation module is used to perform FRFT operation on the pulse echo of each range unit in the current orientation under the condition of FRFT transformation parameters to obtain the detection statistics corresponding to each distance unit; the detection statistics corresponding to the i-th distance unit are The amplitude result obtained by FRFT operation, each distance unit includes multiple pulse echoes, and the number of pulse echoes in each distance unit is the same as the number of channels in the FRFT domain; The first color group output module is used to detect the maneuvering target in the distance unit according to the detection statistic corresponding to each distance unit, and output the first color group; the first color group includes the color corresponding to each distance unit; The non-coherent accumulation module is used to non-coherently accumulate the pulse echoes of each range unit in the current azimuth to obtain the average value of the amplitude; The second color output module is used to detect the maneuvering target of the distance unit according to the amplitude average value of each distance unit, and output the second color group; the second color group includes the color corresponding to each distance unit; the the colors in the second color set do not overlap the colors in the first color set; Said detecting the maneuvering target of the distance unit according to the average value of the amplitude of each distance unit, and outputting the second color group specifically includes: According to the average value of the amplitude of all range cells, based on the two-dimensional constant false alarm detection method, it is judged whether there is a maneuvering target in each range cell; When there is a maneuvering target in the kth distance unit, output a second color at the position corresponding to the kth distance unit; When there is no maneuvering target in the kth distance unit, the second color is not output at the position corresponding to the kth distance unit; Obtain the second color output results corresponding to all the distance units in sequence to obtain the second color group; The maneuvering target detection result color display module is used to superimpose the first color group and the second color group to obtain the color display of the maneuvering target detection result at the current position; The updating module is used to update the scanning azimuth of the antenna, and return to the echo acquisition module to detect the echo of the next scanning azimuth.

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