CN103809162A - Constant false alarm detection method for outer transmitter-based radar - Google Patents

Abstract

The invention belongs to the field of a radar constant false alarm detection technology, and discloses a constant false alarm detection method for outer transmitter-based radar. The constant false alarm detection method for the outer transmitter-based radar comprises the steps of acquiring the distance-Doppler matrix A of the outer transmitter-based radar; correcting elements in the distance-Doppler matrix A, so as to obtain a corrected detection matrix B; performing constant false alarm detection on the matrix B, so as to obtain a matrix C; performing amplitude compensation on non-zero elements in the matrix C, so as to obtain a matrix D; dividing the matrix D into a matrix E and a matrix F; and respectively performing twice ordering and twice point getting on the matrix E and the matrix F, and finally obtaining a constant false alarm detection result.

Description

A kind of external radiation source radar CFAR detection detection method

Technical field

The invention belongs to radar CFAR detection detection technique field, particularly a kind of external radiation source radar CFAR detection detection method.

Background technology

CFAR detection is the important component part of various Radar Signal Processing Systems, particularly external radiation radar system.The object detecting is mainly that the impact point being mingled in noise, clutter is extracted, and will avoid the appearance of false-alarm point simultaneously, thereby improves the precision of back end signal processing.

Conventional CFAR detection method mainly contains slow thresholding CFAR detection and fast thresholding CFAR detection at present.Slow thresholding CFAR detection method is, for detection platform, a unified threshold value is set, every element higher than this fixed threshold, just set it as impact point output, the mode of this clean cut, for the smooth situation of detection platform, can obtain good detection performance, but there is the situation on landslide for detection platform, can make false-alarm point increase, and likely real goal " be cut ", there is the shortcoming same with slow thresholding CFAR Methods in fast thresholding CFAR Methods.In addition, in engineering, also conventional two-stage thresholding carries out target detection, detection platform is divided near region, far field two parts, for near region arranges a high threshold value, for far field arranges a low threshold value, although the detection method of raising near region thresholding this can reduce false-alarm point, has also reduced the detection probability of target simultaneously.In prior art, in the time that detection platform exists landslide phenomenon, traditional CFAR detection method can make false-alarm point increase, thereby causes the signal processing of rear end to reach capacity, particularly, in the low external radiation source radar system of target signal to noise ratio, it is particularly evident that this shortcoming shows.

Summary of the invention

The object of the invention is to propose a kind of external radiation source radar CFAR detection detection method.Guaranteeing to detect under the prerequisite of performance, reducing the quantity of false-alarm point, meeting the demand of external radiation source Radar Targets'Detection, can realize the detection to moving target.

For realizing above-mentioned technical purpose, the present invention adopts following technical scheme to be achieved.

A kind of external radiation source radar CFAR detection detection method, is characterized in that, comprises the following steps:

S1: the distance-Doppler matrix A of obtaining external radiation source radar; Every row element in described distance-Doppler matrix A, divided by corresponding element mean value, is obtained revising rear detection matrix B; Carry out CFAR pre-detection to detecting matrix B after described correction, obtain Matrix C; Describedly carry out CFAR pre-detection and comprise the following steps revising rear detection matrix B: the mean value that detects the every column element of matrix B after revising is multiplied by the detection coefficient of setting, draws the Doppler passage detection threshold value corresponding with revising the every column element of rear detection matrix B; After correction, detect in the every column element of matrix B, the element that is greater than corresponding Doppler's passage detection threshold value is retained, will be less than or equal to the element zero setting of corresponding Doppler's passage detection threshold value;

S2: nonzero element in Matrix C is carried out to Amplitude Compensation, obtain matrix D; Using capable the front p of matrix D as matrix Ε, using capable of matrix F the rear q of matrix D, the line number that p and q sum are matrix D; Every row element in matrix Ε is carried out to rearranging from big to small, obtain matrix G; Every row element in matrix F is carried out to rearranging from big to small, obtain matrix H;

S3: in the i row element of matrix G, take out a maximum r element, form 1 × r rank matrix g _i, i gets 1 to p; By matrix g ₁to g _pbe sequentially arranged in order a line, form one-dimension array X; In the j row element of matrix H, take out a maximum t element, form 1 × t rank matrix h _j, j gets 1 to q; By matrix h ₁to h _qbe sequentially arranged in order a line, form one-dimension array Y;

S4: the each element in one-dimension array X is carried out to rearranging from big to small, obtain one-dimension array W; Each element in one-dimension array Y is carried out to rearranging from big to small, obtain one-dimension array T; Front d element in front s element in one-dimension array W and one-dimension array T merged into new one-dimension array Z, and the each element in one-dimension array Z is CFAR detection result (comprising the amplitude of corresponding impact point).

Feature of the present invention and further improvement are:

In step S1, external radiation source radar obtains echoed signal by main antenna, obtains reference signal by auxiliary antenna; Then echoed signal and reference signal are carried out that clutter offsets, matched filtering processing, obtain distance-Doppler matrix A; Distance-Doppler matrix A is m × n rank matrixes, and m is the distance port number of external radiation source radar, and n is Doppler's port number of external radiation source radar.

In step S1, adjust the distance-Doppler matrix A is revised, described in adjust the distance-Doppler matrix A revise and comprise the following steps:

Calculate the capable element mean value chanel of e of distance-Doppler matrix A _e:

${\mathrm{chanel}}_e=\frac{\underset{f=1}{\overset{n}{\mathrm{\Σ}}}{a}_{\mathrm{ef}}}{n}$

Wherein, a _effor the element of the capable f row of e in distance-Doppler matrix A, e gets 1 to m, and f gets 1 to n;

Then, by the element a of capable e of distance-Doppler matrix A f row _efdivided by chanel _e, obtain the element a of the capable f row of the e of distance-Doppler matrix A _efmodified value;

After adjust the distance-Doppler matrix A is revised, obtain revising rear detection matrix B.

In step S2, describedly nonzero element in Matrix C carried out to Amplitude Compensation comprise the following steps: find out nonzero element in Matrix C, according to following formula, the nonzero element in Matrix C is compensated:

Wherein, arbitrary nonzero element in representing matrix C,

line number in Matrix C is c0, represent the capable element mean value of c0 in distance-Doppler matrix A;

Then, in Matrix C, will

replace corresponding nonzero element, thereby obtain matrix D.

In step S3, described one-dimension array X is: X=[g ₁..., g _i..., g _p], described one-dimension array Y is: Y=[h ₁..., h _i..., h _q].

Beneficial effect of the present invention is: 1) the present invention has carried out amplitude correction to detecting matrix, has alleviated the impact on detection platform landslide, compared with the slow thresholding CFAR detection of tradition method, has improved the detection performance of target.2) the present invention has carried out matrix division to detecting matrix, and respectively the matrix after dividing has been carried out two minor sorts, got for twice a little, compared with the slow thresholding CFAR detection of tradition method, in guaranteeing to detect performance, has reduced the quantity of false-alarm point.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of external radiation of the present invention source radar CFAR detection detection method;

Fig. 2 a is the schematic diagram of original detection platform;

Fig. 2 b uses external radiation of the present invention source radar CFAR detection detection method to carry out the schematic diagram of the detection platform after amplitude correction;

Fig. 3 a is the testing result schematic diagram of the slow thresholding CFAR detection method of tradition;

Fig. 3 b is the testing result schematic diagram of external radiation of the present invention source radar CFAR detection detection method;

Fig. 4 is that the slow thresholding CFAR detection method of tradition is at the testing result schematic diagram reducing after detection threshold.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described:

With reference to Fig. 1, it is the schematic flow sheet of a kind of external radiation of the present invention source radar CFAR detection detection method.This external radiation source radar CFAR detection detection method comprises the following steps:

S1: the distance-Doppler matrix A of obtaining external radiation source radar; Be described as follows: external radiation source radar obtains echoed signal by main antenna, obtain reference signal (being for example direct-path signal) by auxiliary antenna; Then echoed signal and reference signal are carried out that clutter offsets, matched filtering processing, (distance-Doppler matrix A is two-dimensional detection matrix to obtain distance-Doppler matrix A; Distance-Doppler matrix A is m × n rank matrixes, and m is the distance port number of external radiation source radar, and n is Doppler's port number of external radiation source radar.Distance-Doppler matrix A can be expressed as:

$A=\left[\begin{array}{cccc}{a}_{11}& a_{12}& \·\·\·& a_{1n}\\ a_{21}& a_{22}& \·\·\·& a_{2n}\\ \·& \·& \·& \·\\ \·& \·& \·& \·\\ \·& \·& \·& \·\\ a_{m1}& a_{m2}& \·\·\·& a_{\mathrm{mm}}\end{array}\right]$

Wherein, a _effor the element in matrix A, e gets 1 to m, and f gets 1 to n.

After obtaining distance-Doppler matrix A, every row element in distance-Doppler matrix A is revised, obtain revising rear detection matrix B; Be described as follows:

Revise along adjust the distance-Doppler of distance dimension matrix A, the process that above-mentioned adjusting the distance-Doppler matrix A is revised comprises the following steps:

Calculate the capable element mean value chanel of e of distance-Doppler matrix A _e:

${\mathrm{chanel}}_e=\frac{\underset{f=1}{\overset{n}{\mathrm{\Σ}}}{a}_{\mathrm{ef}}}{n}$

Wherein, a _effor the element of the capable f row of e in distance-Doppler matrix A, e gets 1 to m.

Then, by the element a of capable e of distance-Doppler matrix A f row _efdivided by chanel _e, obtain the element a of the capable f row of the e of distance-Doppler matrix A _efmodified value; F gets 1 to n.

After adjust the distance-Doppler matrix A is revised, obtain revising rear detection matrix B.Now, preserve the mean value of the every row element of distance-Doppler matrix A.

After obtaining the rear detection of correction matrix B, carry out CFAR pre-detection along Doppler's dimension to revising rear detection matrix B, obtain Matrix C.Be described as follows:

Calculate the element mean value of each Doppler's passage according to following formula:

$k_f=\frac{\underset{e=1}{\overset{m}{\mathrm{\Σ}}}{b}_{\mathrm{ef}}}{m}$

Wherein, b _efrepresent to detect after revising the element of the capable f row of e in matrix B, k _frepresent the element mean value (detecting the element mean value of f row in matrix B after namely revising) of f Doppler passage.

Then calculate the detection threshold value of each Doppler's passage, undertaken by following formula:

gate _f=k _f*coeff

Wherein, coeff is for setting constant, and it represents detection coefficient; Gate _frepresent the detection threshold value of f Doppler passage.

By the element of f Doppler passage (detecting the f column element of matrix B after revising) the threshold value gate of passage therewith _fcontrast, the element higher than threshold value is retained, by the element zero setting lower than threshold value.

After element in all Doppler's passages is detected, obtain Matrix C.

S2: after obtaining Matrix C, nonzero element in Matrix C is carried out to Amplitude Compensation, obtain matrix D, be described as follows:

Load the element mean value of every row in distance-Doppler matrix A, find out nonzero element in Matrix C, according to following formula, the nonzero element in Matrix C is compensated:

${\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA0000463046170000022.png"\; state="\{\{state\}\}">d</figure-callout>}}_{\stackrel{\&OverBar;}{0}}=\frac{{\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="HDA0000463046170000022.png"\; state="\{\{state\}\}">c</figure-callout>}}_{\stackrel{\&OverBar;}{0}}}{{\mathrm{<figure-callout\; id="0"\; label="chanel"\; filenames="HDA0000463046170000022.png"\; state="\{\{state\}\}">chanel</figure-callout>}}_{\stackrel{\&OverBar;}{0}}}$

Wherein,

arbitrary nonzero element in representing matrix C, line number in Matrix C is c0,

represent the capable element mean value of c0 in distance-Doppler matrix A;

Then, in Matrix C, will

replace corresponding nonzero element, thereby obtain matrix D.

Right after obtaining matrix D, matrix D is divided into two matrixes.Be described as follows:

Using capable the front p of matrix D as matrix Ε, using capable of matrix F the rear q of matrix D, the line number that p and q sum are matrix D, it is evident that, matrix Ε is p × n rank matrixes, and matrix F is q × n rank matrixes.

The partition process of matrix D can be expressed as:

$D_{m*n}=\left[\begin{array}{c}{E}_{p*n}\\ F_{q*n}\end{array}\right]$

Matrix Ε and matrix F represent the detection matrix being made up of different distance passage, and wherein, matrix Ε represents closely (near region) detection matrix, and matrix F represents that (far field) detects matrix at a distance.

After obtaining matrix Ε and matrix F, the every row element in matrix Ε is carried out to rearranging from big to small by amplitude, obtain matrix G; Every row element in matrix F is carried out to rearranging from big to small by amplitude, obtain matrix H.Because element amplitude corresponding to real goal is greater than the same amplitude apart from all the other elements in passage, by apart from passage sequence, be convenient to each element apart from corresponding real goal in passage to screen.

S3: after obtaining matrix G and matrix H, in the i row element of matrix G, r element of taking-up amplitude maximum, forms 1 × r rank matrix g _i, i gets 1 to p; 1 × r rank matrix g _ican be expressed as:

g _i=[g _i1,g _i2...,g _ir]

In the j row element of matrix H, t element of taking-up amplitude maximum, forms 1 × t rank matrix h _j, j gets 1 to q; 1 × t rank matrix h _jcan be expressed as:

h _j=[h _j1,h _j2,...,h _jt]

By above-mentioned steps, can filter out fixed number point of destination in apart from passage each, by the value of r and t, can guarantee to get all impact points, avoid the loss of impact point, also reduce the quantity of false-alarm point simultaneously.

By matrix g ₁to g _pbe sequentially arranged in order a line, form one-dimension array X; By matrix h ₁to h _qbe sequentially arranged in order a line, form one-dimension array Y; One-dimension array X and one-dimension array Y are expressed as:

X=[g ₁,...,g _i,...,g _p]Y=[h ₁,...,h _j,...,h _q]

Through after above-mentioned sequence gets point process, by two detection arrays that detect matrixes and be converted into two one dimensions, one-dimension array X has comprised all impact points of closely going up, and one-dimension array Y has comprised all impact points on remote.

S4: the each element in one-dimension array X is carried out to rearranging from big to small by amplitude, obtain one-dimension array W; Each element in one-dimension array Y is carried out to rearranging from big to small by amplitude, obtain one-dimension array T.

Front d element in front s element in one-dimension array W and one-dimension array T merged into new one-dimension array Z, and the each element in one-dimension array Z is the amplitude of the corresponding impact point that detects.One-dimension array Z can be expressed as:

Z=[W,T]=[w ₁,w ₂...,w _s,t ₁,t ₂...,t _d]

Wherein, w ₁, w ₂and w _sbe respectively the 1st element of one-dimension array W, the 2nd element and s element; t ₁, t ₂and t _dbe respectively the 1st element of one-dimension array T, the 2nd element and d element.

In step S4, in one-dimension array W and dimension group T, only get several points of amplitude maximum, further filtering false-alarm point.

After obtaining one-dimension array Z, just can carry out subsequent treatment according to the element of one-dimension array Z.For example, the processing module that all elements of one-dimension array Z is passed to rear end is processed.

Below by a specific embodiment, the invention will be further described:

External radiation source radar data to a frame actual measurement detects, in these data, comprise two targets (comprise two targets: target 1 and target 2), all the other parameters are set to: total distance port number m is 400, Doppler's port number n is 2000, the distance port number of shielding is 10, it is 250 apart from port number p that matrix is divided rear near region, far field is 140 apart from port number q, for the first time after sequence, the number of data points r getting in apart from passage two submatrixs each, t is respectively 16, 8(r=16, t=8), for the second time after sequence, the number of data points s getting in two one-dimension array, d is respectively 60, 40(s=60, d=40).

Externally radiation source radar receives to such an extent that echoed signal and reference signal carry out that clutter offsets, matched filtering, obtain distance-Doppler matrix, adjust the distance-Doppler of the method matrix that adopts the present invention to propose carries out amplitude correction, and the result of correction and raw data are contrasted.With reference to Fig. 2 a, it is the schematic diagram of original detection platform; With reference to Fig. 2 b, for using the inventive method to carry out the schematic diagram of the detection platform after amplitude correction.Fig. 2 a and Fig. 2 b are contrasted, can find, detection platform before correction is obvious in the phenomenon of closely locating to come down, the amplitude of real goal is lower than the amplitude of landslide place clutter point, and the detection platform of carrying out after amplitude correction becomes more smooth, target is more outstanding, and validity and the superiority of CFAR detection method of the present invention is described.

Adopting method of the present invention to proceed follow-up processing to revised detection matrix, final result and the testing result of slow gate method are contrasted, with reference to Fig. 3 a, is the testing result schematic diagram of the slow thresholding CFAR detection of tradition method; With reference to Fig. 3 b, it is the testing result schematic diagram of external radiation of the present invention source radar CFAR detection detection method.Fig. 3 a and Fig. 3 b are contrasted, can find, under the identical prerequisite of detection coefficient, slow thresholding CFAR detection method only detects a target, there is the situation of track rejection, and detect a large amount of false-alarm points at landslide place closely, and external radiation of the present invention source radar CFAR detection detection method has also reduced the quantity of false-alarm point in target complete being detected, has further verified the validity of external radiation of the present invention source radar CFAR detection detection method.

In the time adopting the slow thresholding CFAR detection method of tradition, reduce detection coefficient (namely having reduced detection threshold), all the other conditions are constant, and raw data is detected again.With reference to Fig. 4, for the slow thresholding CFAR detection of tradition method is at the testing result schematic diagram reducing after detection threshold.As seen from Figure 4, after detection coefficient reduces, although slow thresholding CFAR detection method has detected two targets, but also there is more false-alarm point simultaneously, known in conjunction with Fig. 3, compared with the slow thresholding CFAR detection of tradition method, external radiation of the present invention source radar CFAR detection detection method has obvious advantage in detection performance.

In sum, the present invention, by the element detecting in matrix being carried out to amplitude correction apart from passage, reduces the impact on detection platform landslide; Detect detecting matrix by Doppler's passage, retained the point of thresholding; The point of crossing thresholding to detecting in matrix carries out Amplitude Compensation; Detection matrix is divided into two, then carries out respectively two minor sorts by amplitude size, get for twice a little, reduced the quantity of false-alarm point.

Obviously, those skilled in the art can carry out various changes and modification and not depart from the spirit and scope of the present invention the present invention.Like this, if within of the present invention these are revised and modification belongs to the scope of the claims in the present invention and equivalent technologies thereof, the present invention is also intended to comprise these changes and modification interior.

Claims (5)

1. an external radiation source radar CFAR detection detection method, is characterized in that, comprises the following steps:

S1: the distance-Doppler matrix A of obtaining external radiation source radar; Element in described distance-Doppler matrix A is revised, obtained revising rear detection matrix B; Carry out CFAR pre-detection to detecting matrix B after described correction, obtain Matrix C; Describedly carry out CFAR pre-detection and comprise the following steps revising rear detection matrix B: the mean value that detects the every column element of matrix B after revising is multiplied by the detection coefficient of setting, draws the Doppler passage detection threshold value corresponding with revising the every column element of rear detection matrix B; After correction, detect in the every column element of matrix B, the element that is greater than corresponding Doppler's passage detection threshold value is retained, will be less than or equal to the element zero setting of corresponding Doppler's passage detection threshold value;

S2: nonzero element in Matrix C is carried out to Amplitude Compensation, obtain matrix D; Using capable the front p of matrix D as matrix Ε, using capable of matrix F the rear q of matrix D, the line number that p and q sum are matrix D; Every row element in matrix Ε is carried out to rearranging from big to small, obtain matrix G; Every row element in matrix F is carried out to rearranging from big to small, obtain matrix H;

S3: in the i row element of matrix G, take out a maximum r element, form 1 × r rank matrix g _i, i gets 1 to p; By matrix g ₁to g _pbe sequentially arranged in order a line, form one-dimension array X; In the j row element of matrix H, take out a maximum t element, form 1 × t rank matrix h _j, j gets 1 to q; By matrix h ₁to h _qbe sequentially arranged in order a line, form one-dimension array Y;

S4: the each element in one-dimension array X is carried out to rearranging from big to small, obtain one-dimension array W; Each element in one-dimension array Y is carried out to rearranging from big to small, obtain one-dimension array T; Front d element in front s element in one-dimension array W and one-dimension array T merged into new one-dimension array Z, and the each element in one-dimension array Z is CFAR detection result.

2. a kind of external radiation as claimed in claim 1 source radar CFAR detection detection method, is characterized in that, in step S1, external radiation source radar obtains echoed signal by main antenna, obtains reference signal by auxiliary antenna; Then echoed signal and reference signal are carried out that clutter offsets, matched filtering processing, obtain distance-Doppler matrix A; Distance-Doppler matrix A is m × n rank matrixes, and m is the distance port number of external radiation source radar, and n is Doppler's port number of external radiation source radar.

3. a kind of external radiation as claimed in claim 1 source radar CFAR detection detection method, is characterized in that, the element in step S1, adjust the distance-Doppler matrix A is revised, described in adjust the distance-Doppler matrix A revise and comprise the following steps:

Calculate the capable element mean value chanel of e of distance-Doppler matrix A _e:

${\mathrm{chanel}}_e=\frac{\underset{f=1}{\overset{n}{\mathrm{\&Sigma;}}}{a}_{\mathrm{ef}}}{n}$

Wherein, a _effor the element of the capable f row of e in distance-Doppler matrix A, e gets 1 to m, and f gets 1 to n; Then, by the element a of capable e of distance-Doppler matrix A f row _efdivided by chanel _e, obtain the element a of the capable f row of the e of distance-Doppler matrix A _efmodified value;

After element in adjust the distance-Doppler matrix A is revised, obtain revising rear detection matrix B.

4. a kind of external radiation as claimed in claim 3 source radar CFAR detection detection method, it is characterized in that, in step S2, describedly nonzero element in Matrix C carried out to Amplitude Compensation comprise the following steps: find out nonzero element in Matrix C, according to following formula, the nonzero element in Matrix C is compensated:

$d_{\stackrel{\&OverBar;}{0}}=\frac{c_{\stackrel{\&OverBar;}{0}}}{{\mathrm{chanel}}_{\stackrel{\&OverBar;}{0}}}$

Wherein,

arbitrary nonzero element in representing matrix C,

line number in Matrix C is c0,

represent the capable element mean value of c0 in distance-Doppler matrix A;

Then, in Matrix C, will replace corresponding nonzero element, thereby obtain matrix D.

5. a kind of external radiation as claimed in claim 1 source radar CFAR detection detection method, is characterized in that, in step S3, described one-dimension array X is: X=[g ₁..., g _i..., g _p], described one-dimension array Y is: Y=[h ₁..., h _i..., h _q].

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