CN106872954A - A kind of hypersonic platform clutter recognition and motive target imaging method - Google Patents

Abstract

The invention belongs to Radar Technology field, a kind of hypersonic platform clutter recognition and motive target imaging method are disclosed, including：Obtain the echo-signal of each reception antenna；Carry out pulse compression and contracting of baroclining is gone in orientation, obtain distance domain Azimuth Compression frequency domain echo-signal；First step coarse search is carried out to radial velocity, and obtains moving target steering vector and Clutter steering vector；Optimal weight vector is calculated, and carries out clutter recognition, obtain transient echo data；Carry out simplifying Radon conversion, obtain radial velocity fine estimation；Accurate compensation radial velocity, obtains movement destination image.The present invention solves the problems, such as that existing method clutter recognition and moving target parameter Estimation are inaccurate, improves the clutter recognition performance of hypersonic platform radar, improves the letter miscellaneous noise ratio of moving target.

Description

A kind of hypersonic platform clutter recognition and motive target imaging method

Technical field

The invention belongs to Radar Technology field, more particularly to a kind of hypersonic platform clutter recognition and motive target imaging Method, for the clutter recognition and motive target imaging of hypersonic platform Multichannel radar.

Background technology

Hypersonic aircraft is a kind of new optimal in structure of recent domestic research and development energetically, with a high speed High motor-driven the characteristics of, current air defence system can be allowed to be difficult to detect to it.Hypersonic aircraft flies in 20km-100km Near space, its flying speed is more than 5 times of velocities of sound, it might even be possible to reach 20 times of velocities of sound, and can be in 1 hour to the whole world In the range of sensitive target carry out precision strike.Therefore, to combine aerospace field crowd multi-disciplinary for hypersonic aircraft New technology, represents the research and development direction of following aerospace field, be considered as in military affairs after stealth technology again One focus technology field, an important directions as 21 century Global Aerospace career development.

At present, hypersonic aircraft is greatly developed including the multiple country including the U.S. and China, but big portion The R＆D work for dividing concentrates on the aspects such as air force, propulsion and material, and near space hypersonic aircraft is in detection energy Research in terms of power has blank, that is, lack effective communication and information, monitoring, reconnaissance platforms.Existing airborne radar pair Use aircraft and satellite more ground observation platform, and imaging and Ground moving target detection phase are carried out using hypersonic radar platform There is advantages below for airborne and spaceborne radar platform：Hypersonic platform radar can observe energy compared to spaceborne radar Fainter target；The observation scope of hypersonic platform radar is much larger than airborne radar；Hypersonic platform radar has height Motor-driven feature, can avoid detected and hit；Hypersonic platform radar has filled up the blank of near space earth observation. Therefore, the research for being detected over the ground for hypersonic platform radar, has very important significance.

Due to the high-speed motion of hypersonic radar platform, its radar return can have doppler ambiguity, and move mesh Mark is often submerged in the strong clutter in ground, therefore, it is necessary to be carried out using Multichannel radar system miscellaneous before motive target imaging Ripple suppresses.In existing imaging space and time adaptive processing (ISTAP) and chirp In typical the multichannel clutter recognition and motive target imaging method such as Fourier transform (CFT), due to moving target Unknown parameters, thus clutter recognition is carried out using arbitrary parameter, and motive target imaging is carried out using static target parameter, this A little processing methods can all cause clutter recognition and motive target imaging hydraulic performance decline, and the letter for seriously reducing moving target miscellaneous is made an uproar Than can also cause follow-up moving object detection hydraulic performance decline.Also, the estimation in existing method to moving target parameter is used The method of direct search so that operand is dramatically increased, and cause the decline of Parameter Estimation Precision.

The content of the invention

For the deficiency of above-mentioned prior art, the present invention proposes a kind of hypersonic platform clutter recognition and moving target Imaging method, can effectively solve the problems, such as that existing method clutter recognition and moving target parameter Estimation are inaccurate, improve superb The clutter recognition performance of velocity of sound platform radar, improves the letter miscellaneous noise ratio of moving target.

To reach above-mentioned purpose, the present invention is adopted the following technical scheme that and is achieved.

A kind of hypersonic platform clutter recognition and motive target imaging method, methods described comprise the following steps：

Step 1, radar receiver obtains k-th echo-signal of reception antenna, to k-th echo-signal of reception antenna Do the Fourier transformation of fast time dimension, obtain k-th reception antenna apart from frequency domain echo signal, and to k-th reception antenna Pulse compression is carried out using frequency domain reference signal apart from frequency domain echo signal, obtain k-th reception antenna apart from frequency domain-side Position time domain echo-signal；

Oblique wave filter is removed in step 2, the orientation for constructing k-th reception antenna, according to the orientation of k-th reception antenna Go oblique wave filter carrying out orientation and going contracting of baroclining, and entering successively apart from frequency domain-orientation time domain echo-signal to k-th reception antenna The inverse Fourier transform of the Fourier transformation and fast time dimension of the slow time dimension of row, obtains k-th distance domain-orientation of reception antenna The echo-signal in compression frequency domain；

Step 3, makes k=1,2 ..., K, so as to respectively obtain the K distance domain of reception antenna-Azimuth Compression frequency domain Echo-signal；The echo-signal of the distance domain of the K reception antenna-Azimuth Compression frequency domain is arranged in order, echo is obtained Signal；

Step 4, sets estimate scope and the rough estimate interval of moving target radial velocity, radially fast to moving target Degree carries out first step coarse search, obtains the first step rough estimate value of moving target radial velocity, and corresponding moving target Steering vector and Clutter steering vector；

Step 5, the optimal weight vector coefficient required for obtaining clutter recognition, according to the optimal weight vector coefficient to search Echo-signal carries out clutter recognition, obtains the Moving Target Return data after clutter recognition；

Step 6, constructs rough radial velocity penalty function, and the Moving Target Return data after the clutter recognition are carried out Distance dimension Fourier transformation and azimuth dimension inverse Fourier transform, obtain apart from frequency domain-orientation time domain echo-signal, then according to institute Rough radial velocity penalty function is stated to compensate the rough radial velocity apart from frequency domain-orientation time domain echo-signal, Obtain the echo-signal after rough radial velocity compensation；Row distance is entered to the echo-signal after the rough radial velocity compensation again Dimension inverse Fourier transform, obtains the two-dimensional time-domain echo-signal of moving target；

Step 7, the two-dimensional time-domain echo-signal to the moving target carries out Radon conversion, realizes moving target radially The second step of speed accurately estimates, obtains the fine estimation of moving target radial velocity；

Step 8, the two-dimensional time-domain echo-signal to the moving target enters row distance dimension Fourier transformation, obtains distance frequency The Moving Target Return signal of domain-orientation time domain；Construction residual radial velocity penalty function, mends according to the residual radial velocity The radial velocity for repaying function pair moving target is accurately compensated, the echo-signal after accurately being compensated；

Step 9, azimuth dimension Fourier transformation and the inverse Fourier of distance dimension are carried out to the echo-signal after the accurate compensation Conversion, the moving target signal for being focused on.

The hypersonic platform clutter recognition and motive target imaging method of present invention offer are by the footpath to moving target Rough and accurate Two-step estimation is carried out to speed, the radar system based on ultrasound platform high is efficiently solved due to moving target The problem that the clutter recognition and imaging performance that unknown parameters are caused decline, and improve the estimated accuracy of moving target parameter. Specifically, the present invention has advantages below compared with prior art：

First, it is miscellaneous due to carrying out multichannel using rough estimate radial velocity in the Clutter suppression algorithm of present invention design Ripple suppresses, and can reduce moving target unknown parameters and cause clutter recognition hydraulic performance decline, and the letter for effectively improving moving target miscellaneous is made an uproar Than；

Second, the inventive method carries out Two-step estimation by the radial velocity to moving target, significantly carries than existing methods The estimated accuracy of parameter high, also for follow-up moving-target detection provides preferably possibility；

3rd, in the two-step method operating process that the inventive method is proposed, because the first step can be determined using rough estimate The approximate range of moving target radial velocity, and effectively realize clutter recognition so that second step accurately estimates that radial velocity can be with Searched in a small range and realized, amount of calculation is effectively reduced than existing methods.

Brief description of the drawings

In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing The accompanying drawing to be used needed for having technology description is briefly described, it should be apparent that, drawings in the following description are only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with Other accompanying drawings are obtained according to these accompanying drawings.

Fig. 1 is the stream of a kind of hypersonic platform clutter recognition provided in an embodiment of the present invention and motive target imaging method Cheng Tu；

Fig. 2 (a) is the echo-signal schematic diagram that radar is received；

Fig. 2 (b) is traditional ISTAP processing method clutter recognition result figures；

Fig. 2 (c) is traditional CFT processing method clutter recognition result figures；

Fig. 2 (d) is the inventive method clutter recognition result figure；

Fig. 3 is the clutter recognition performance comparison figure using traditional ISTAP, CFT method and the inventive method；

Fig. 4 (a) is traditional ISTAP processing method motive target imaging result figures；

Fig. 4 (b) is traditional CFT processing method motive target imaging result figures；

Fig. 4 (c) is using the motive target imaging result figure of the inventive method；

Fig. 5 is using the moving target radial velocity estimated accuracy comparison diagram of traditional ISTAP, CFT method and the inventive method.

Specific embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Site preparation is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than whole embodiments.It is based on Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made Embodiment, belongs to the scope of protection of the invention.

The embodiment of the present invention provides a kind of hypersonic platform clutter recognition and motive target imaging method, as shown in figure 1, Methods described comprises the following steps：

Step 1, radar receiver obtains k-th echo-signal of reception antenna, to k-th echo-signal of reception antenna Do the Fourier transformation of fast time dimension, obtain k-th reception antenna apart from frequency domain echo signal, and to k-th reception antenna Pulse compression is carried out using frequency domain reference signal apart from frequency domain echo signal, obtain k-th reception antenna apart from frequency domain-side Position time domain echo-signal.

In step 1：Radar receiver obtains k-th echo-signal s of reception antenna_k(t_r, t_a) be：

s_k(t_r, t_a)=w_r(t_r-τ_k)w_a(t_a-t₀)exp[j2πf₀(t_r-τ_k)]exp[jπγ(t_r-τ_k)²]

Wherein, k=1,2 ..., K, K represent reception antenna number, t_rRepresent distance to fast time, t_aRepresent that orientation is slow Time, w_r() represents echo-signal distance to time window function, w_a() represents echo-signal orientation time window function, t₀ The center hold moment of moving target is represented, j represents imaginary unit, f₀Transmission signal carrier frequency is represented, γ represents that transmission signal is adjusted Frequency, τ_kRepresent k-th time delay of antenna, τ_k=2R_k(t_a)/c, c represent propagation velocity of electromagnetic wave, R_k(t_a) represent t_aWhen K-th antenna is carved the distance between to moving target, R₀Represent the minimum distance between image scene center and hypersonic platform, v_rRepresent the radial velocity of moving target, v_aRepresent The tangential velocity of moving target, v represents radar platform movement velocity, d_kRepresent k-th antenna it is relative with the 1st antenna away from From d_k=(k-1) d, d represent the relative distance of two neighboring antenna；

To k-th echo-signal s of reception antenna_k(t_r, t_a) make the Fast Fourier Transform (FFT) FFT of fast time dimension, obtain away from Off-frequency domain echo-signal, and frequency domain reference signal H is used to the frequency domain echo signal_r(f_r) pulse compression is carried out, realize distance With filtering, obtain k-th reception antenna apart from frequency domain-orientation time domain echo-signal s_k(f_r, t_a) be：

s_k(f_r, t_a)=FFT_r[s_k(t_r, t_a)]×H_r(f_r)

=W_r(f_r)w_a(t_a-t₀)exp(-j2π(f₀+f_r)τ_k)

Wherein, f_rRepresent frequency of distance, FFT_r[] represents the FFT operations of fast time dimension, frequency domain reference signal H_r(f_r)= exp[jπ(f₀+f_r)²/ γ], W_r() represents echo-signal apart from frequency domain window function.

Oblique wave filter is removed in step 2, the orientation for constructing k-th reception antenna, and the orientation according to k-th reception antenna is gone Oblique wave filter carries out orientation and goes contracting of baroclining to k-th reception antenna apart from frequency domain-orientation time domain echo-signal, and carries out successively The inverse Fourier transform of the Fourier transformation and fast time dimension of slow time dimension, obtains k-th distance domain of reception antenna-orientation pressure The echo-signal of contracting frequency domain.

Step 2 is specially：Oblique wave filter H is removed in the orientation for constructing k-th reception antenna_{A, k}(f_r, t_a)：

To k-th reception antenna apart from frequency domain-orientation time domain echo-signal s_k(f_r, t_a) contracting treatment of baroclining is gone as orientation, And carry out the inverse Fourier transform of the Fourier transformation and fast time dimension of slow time dimension successively, obtain k-th reception antenna away from The echo-signal s of delocalization-Azimuth Compression frequency domain_k(t_r, f_a)：

s_k(t_r, f_a)=IFFT_r[[FFT_a[s_k(f_r, t_a)×H_a, k (f_r, t_a)]]

=w_r(t_r-2R₀/c)W_a(f_a+2v_r/λ-2v²t₀/λR₀)

exp(-j4πR₀/λ)exp[-j2π(f_a+2v_r/λ)d_k/v]

Wherein, v_rThe radial velocity of moving target is represented, λ represents radar emission signal carrier frequency, FFT_a[] represents the slow time The FFT operations of dimension, IFFT_r[] represents the IFFT operations of fast time dimension, W_a() represents echo-signal orientation frequency domain window function.

Step 3, makes k=1,2 ..., K, so as to respectively obtain the K distance domain of reception antenna-Azimuth Compression frequency domain Echo-signal；The echo-signal of the distance domain of the K reception antenna-Azimuth Compression frequency domain is arranged in order, echo is obtained Signal.

Step 3 is specially：The distance domain of the K reception antenna that will be obtained-Azimuth Compression frequency domain echo-signal s₁(t_r, f_a), s₂(t_r, f_a) ..., s_K(t_r, f_a) arranged in sequence, obtain echo-signal matrix s (t_r, f_a)=[s₁(t_r, f_a), s₂(t_r, f_a) ..., s_K(t_r, f_a)]^T, wherein subscript T represent transposition operate, f_aRepresent orientation frequency.

Step 4, sets estimate scope and the rough estimate interval of moving target radial velocity, radially fast to moving target Degree carries out first step coarse search, obtains the first step rough estimate value of moving target radial velocity, and corresponding moving target Steering vector and Clutter steering vector.

Step 4 specifically includes following sub-step：

(4a) sets the maximum estimated value v of moving target radial velocity_{r_range}V is spaced with rough estimate_{r_step}, and obtain Need the total degree P=ceil (v of rough search_{r_range}/v_{r_step}), wherein ceil () represents the number operation that rounds up；

(4b) initialization iterations p=1；

(4c) carries out first step rough estimate to the radial velocity of moving target, obtains velocity estimation median v_{r_temp}=- v_{r_range}/2+p×v_{r_step}；

(4d) makes the value of p plus 1 if p ＜ P, and returns to sub-step (4c), otherwise to obtain all velocity estimations in the middle of Value, asks for the corresponding moving target energy of each velocity estimation median；

(4e) selects to cause the velocity estimation median that moving target energy is maximum, used as the of moving target radial velocity One step rough estimate value v_r0, i.e.,WhereinCorresponding v when representing acquisition maximum_{r_temp}Value； Wherein,

(4f) tries to achieve moving target steering vectorFor：

(4g) tries to achieve Clutter steering vector a_C(f_a) be：

a_C(f_a)=[exp (- j2 π f_ad₁/v)…exp(-j2πf_ad_K/v)]^T。

Step 5, the optimal weight vector coefficient required for obtaining clutter recognition, according to the optimal weight vector coefficient to search Echo-signal carries out clutter recognition, obtains the Moving Target Return data after clutter recognition.

Step 5 specifically includes following sub-step：

(5a) is according to the echo-signal matrix s (t_r, f_a), it is calculated covariance matrix R (f_a)=E [s (t_r, f_a)s^H (t_r, f_a)], wherein E [] is represented and is taken desired operation, and subscript H represents conjugate transposition；

(5b) is according to optimization problem：

Optimal weight vector coefficient required for trying to achieve clutter recognitionFor：

WhereinRepresent corresponding during acquisition minimum value

(5c) is by the optimal weight vector coefficientWith the echo-signal matrix s (t_r, f_a) be multiplied, obtain right Moving Target Return data after the clutter recognition answeredFor：

Step 6, constructs rough radial velocity penalty function, and the Moving Target Return data after the clutter recognition are carried out Distance dimension Fourier transformation and azimuth dimension inverse Fourier transform, obtain apart from frequency domain-orientation time domain echo-signal, then according to institute Rough radial velocity penalty function is stated to compensate the rough radial velocity apart from frequency domain-orientation time domain echo-signal, Obtain the echo-signal after rough radial velocity compensation；Row distance is entered to the echo-signal after the rough radial velocity compensation again Dimension inverse Fourier transform, obtains the two-dimensional time-domain echo-signal of moving target.

Step 6 specifically includes following sub-step：

Construct rough radial velocity penalty functionFor：

Obtain the two-dimensional time-domain echo-signal of moving targetFor：

Wherein IFFT_a[] represents the IFFT operations of slow time dimension, v_{r_res}Represent to rough radial velocity v_r0Compensate Residual radial velocity afterwards, v_{r_res}=v^r-v^r0。

Step 7, the two-dimensional time-domain echo-signal to the moving target carries out Radon conversion, realizes moving target radially The second step of speed accurately estimates, obtains the fine estimation of moving target radial velocity.

It is [v to set and the hunting zone of second step precise search is carried out to the radial velocity of moving target_r0-v_{r_step}/ 2, v_r0 +v_{r_step}/ 2] Radon conversion, and in the hunting zone is carried out, residual radial velocity v is tried to achieve_{r_res}, and obtain moving target footpath To the fine estimation v of speed_{r_est}=v_r0+v_{r_res}。

Specifically, setting carries out the search model of second step precise search to the radial velocity of moving target It is [v to enclose_r0-v_{r_step}/ 2, v_r0+v_{r_step}/ 2], the basis and in the hunting zoneRadon conversion is carried out, wherein ρ is Radon The radius of conversion, θ is the angle of Radon conversion, and δ () is delta function.The peak value of Radon conversion is asked for, at its peak value Radon translation-angles are θ₀, and according to θ₀Try to achieve residual radial velocity v_{r_res}=Δ t_rcotθ₀/cΔt_a, wherein Δ t_rIt is distance Dimension resolution cell width, Δ t_aIt is azimuth dimension resolution cell width.According to residual radial velocity v_{r_res}It is calculated moving target The fine estimation v of radial velocity_{r_est}=v_r0+v_{r_res}。

Step 8, the two-dimensional time-domain echo-signal to the moving target enters row distance dimension Fourier transformation, obtains distance frequency The Moving Target Return signal of domain-orientation time domain；Construction residual radial velocity penalty function, mends according to the residual radial velocity The radial velocity for repaying function pair moving target is accurately compensated, the echo-signal after accurately being compensated.

Obtain the Moving Target Return signal apart from frequency domain-orientation time domainFor：

Construction residual radial velocity penalty functionFor：

Echo-signal s (f after accurately being compensated_r, t_a) be：

Step 9, azimuth dimension Fourier transformation and the inverse Fourier of distance dimension are carried out to the echo-signal after the accurate compensation Conversion, the moving target signal for being focused on.

The moving target signal s (t for being focused on_r, f_a) be：

So far, that is, the movement destination image data of focusing are obtained, hypersonic platform provided in an embodiment of the present invention is miscellaneous Ripple suppresses and motive target imaging method terminates.

Hypersonic platform clutter recognition provided in an embodiment of the present invention and motive target imaging method are by motion mesh Target radial velocity carries out rough and accurate Two-step estimation, efficiently solves the radar system based on ultrasound platform high due to fortune The problem that the clutter recognition and imaging performance that moving-target unknown parameters are caused decline, and improve the estimation of moving target parameter Precision.Specifically, the present invention has advantages below compared with prior art：

First, it is miscellaneous due to carrying out multichannel using rough estimate radial velocity in the Clutter suppression algorithm of present invention design Ripple suppresses, and can reduce moving target unknown parameters and cause clutter recognition hydraulic performance decline, and the letter for effectively improving moving target miscellaneous is made an uproar Than；

Second, the inventive method carries out Two-step estimation by the radial velocity to moving target, significantly carries than existing methods The estimated accuracy of parameter high, also for follow-up moving-target detection provides preferably possibility；

3rd, in the two-step method operating process that the inventive method is proposed, because the first step can be determined using rough estimate The approximate range of moving target radial velocity, and effectively realize clutter recognition so that second step accurately estimates that radial velocity can be with Searched in a small range and realized, amount of calculation is effectively reduced than existing methods.

Hereinafter, above-mentioned beneficial effect of the invention is described further by emulation experiment：

1) simulated conditions：

Emulated using hypersonic platform multichannel SAR GMTI systems, and 4 antenna channels (i.e. M=4) be set, 1st channel emission signal, all passages receive echo-signal simultaneously, and adjacent antenna is at intervals of d=0.5m, the fortune of radar platform Dynamic speed is v=1700m/s (5Mach)；1st channel emission linear waveform signal, bandwidth and the pulsewidth difference of transmission signal It is B_r=200MHz and T_p=12us, transmission signal carrier frequency is f₀=10GHz, pulse recurrence frequency is PRF=1800Hz, frequency modulation Rate is γ=B_r/T_p.Radar platform is 65km with the nearest oblique distance at image scene center.It is provided with radar imagery scene center One moving target point, tangentially and radially speed is respectively 0m/s and 10m/s to moving target.Emulation be also provided with 8 it is static miscellaneous Wave point, its position is respectively (- 100,100), (0,100), (100,100), (- 100,0), (100,0), (- 100, -100), (0, -100), (100, -100).Simulation result is illustrated in emulation content below.

2) emulation content and simulation result：

Emulation 1：Simulation comparison is carried out to clutter recognition treatment using the inventive method and traditional ISTAP and CFT methods. Simulation result is as shown in Fig. 2 wherein, Fig. 2 (a) is using traditional ISTAP processing method clutter recognition result figures；Fig. 2 (b) is Using traditional CFT processing method clutter recognition result figures；Fig. 2 (c) is using the inventive method clutter recognition result figure.

Emulation 2：Using the clutter recognition performance comparison figure of traditional ISTAP, CFT method and the inventive method.Emulation knot Fruit is as shown in Figure 3.

Emulation 3：Simulation comparison is carried out to motive target imaging using the inventive method and traditional ISTAP and CFT methods. Simulation result is as shown in figure 4, wherein, Fig. 4 (a) is using traditional ISTAP processing method motive target imaging result figures；Fig. 4 B () is using traditional CFT processing method motive target imaging result figures；Fig. 4 (c) is using the motion mesh of the inventive method Mark imaging results figure.

Emulation 4：The moving target radial velocity processed using the inventive method and traditional ISTAP and CFT methods is estimated Accuracy comparison.Simulation result is as shown in Figure 5.

3) analysis of simulation result：

Emulation 1：As can be seen that carrying out clutter suppression using traditional ISTAP and CFT methods from Fig. 2 (a) and Fig. 2 (b) System, there is certain loss in moving target energy, and clutter is not totally constrained；As can be seen that adopting from Fig. 2 (c) Clutter recognition is carried out with the inventive method, moving target is fully retained, and clutter is totally constrained.From the contrast of Fig. 2 As can be seen that the inventive method is more preferable than traditional ISTAP and CFT method clutter recognition effects in result.

Emulation 2：From figure 3, it can be seen that moving target radial velocity for 10m/s at, the clutter of the inventive method Suppress letter miscellaneous noise ratio higher, and traditional ISTAP and CFT methods letter miscellaneous noise ratio is relatively low.

Emulation 3：As can be seen that being entered to moving target using traditional ISTAP and CFT methods from Fig. 4 (a) and Fig. 4 (b) Row imaging, imaging results are diffused as multiple points, i.e., moving target is not fully focused；As can be seen that using from Fig. 4 (c) The inventive method is imaged to moving target, and imaging results are focused to a point, this demonstrate that the inventive method is to ultrasound high The validity of fast radar platform motive target imaging.

Emulation 3：From figure 5 it can be seen that high using the moving target radial velocity estimated accuracy that the inventive method is obtained In the moving target radial velocity estimated accuracy obtained using traditional ISTAP, CFT method.

One of ordinary skill in the art will appreciate that：Realizing all or part of step of above method embodiment can pass through Programmed instruction related hardware is completed, and foregoing program can be stored in computer read/write memory medium, and the program exists During execution, the step of including above method embodiment is performed；And foregoing storage medium includes：ROM, RAM, magnetic disc or CD Etc. it is various can be with the medium of store program codes.

The above, specific embodiment only of the invention, but protection scope of the present invention is not limited thereto, and it is any Those familiar with the art the invention discloses technical scope in, change or replacement can be readily occurred in, should all contain Cover within protection scope of the present invention.Therefore, protection scope of the present invention should be based on the protection scope of the described claims.

Claims (10)

1. a kind of hypersonic platform clutter recognition and motive target imaging method, it is characterised in that methods described includes as follows Step：

Step 1, radar receiver obtains k-th echo-signal of reception antenna, and the echo-signal to k-th reception antenna is done soon The Fourier transformation of time dimension, obtain k-th reception antenna apart from frequency domain echo signal, and to k-th reception antenna away from Off-frequency domain echo-signal carries out pulse compression, obtain k-th reception antenna apart from frequency domain-orientation time domain echo-signal；

Oblique wave filter is removed in step 2, the orientation for constructing k-th reception antenna, and tiltedly filter is gone in the orientation according to k-th reception antenna Ripple device carries out orientation and goes contracting of baroclining to k-th reception antenna apart from frequency domain-orientation time domain echo-signal, and when carrying out slow successively Between tie up Fourier transformation and fast time dimension inverse Fourier transform, obtain k-th distance domain-Azimuth Compression of reception antenna frequently The echo-signal in rate domain；

Step 3, makes k=1,2 ..., K, so as to respectively obtain the K echo of the distance domain of reception antenna-Azimuth Compression frequency domain Signal；The echo-signal of the distance domain of the K reception antenna-Azimuth Compression frequency domain is arranged in order, echo-signal is obtained Matrix；

Step 4, sets estimate scope and the rough estimate interval of moving target radial velocity, and moving target radial velocity is entered Row first step coarse search, obtains the first step rough estimate value of moving target radial velocity, and corresponding moving target is oriented to Vector Clutter steering vector；

Step 5, the optimal weight vector coefficient required for obtaining clutter recognition, according to the optimal weight vector coefficient to echo-signal Matrix carries out clutter recognition, obtains the Moving Target Return data after clutter recognition；

Step 6, constructs rough radial velocity penalty function, and row distance is entered to the Moving Target Return data after the clutter recognition Dimension Fourier transformation and azimuth dimension inverse Fourier transform, obtain apart from frequency domain-orientation time domain echo-signal, then according to described thick Slightly the adjust the distance rough radial velocity of frequency domain-orientation time domain echo-signal of radial velocity penalty function is compensated, and obtains rough Echo-signal after radial velocity compensation；The echo-signal after the rough radial velocity compensation is tieed up in inverse Fu enter row distance again Leaf transformation, obtains the two-dimensional time-domain echo-signal of moving target；

Step 7, the two-dimensional time-domain echo-signal to the moving target carries out Radon conversion, realizes moving target radial velocity Second step accurately estimate, obtain the fine estimation of moving target radial velocity；

Step 8, row distance dimension Fourier transformation is entered to the two-dimensional time-domain echo-signal of the moving target, obtain apart from frequency domain- The Moving Target Return signal of orientation time domain；Construction residual radial velocity penalty function, compensates according to the residual radial velocity The radial velocity of function pair moving target is accurately compensated, the echo-signal after accurately being compensated；Wherein remaining radially speed Spend the difference of the radial velocity and the first step rough estimate value of moving target radial velocity for moving target；

Step 9, azimuth dimension Fourier transformation and distance dimension inverse Fourier transform are carried out to the echo-signal after the accurate compensation, The moving target signal for being focused on.

2. a kind of hypersonic platform clutter recognition according to claim 1 and motive target imaging method, its feature exist In in step 1：

Radar receiver obtains k-th echo-signal s of reception antenna_k(t_r,t_a) be：

s_k(t_r,t_a)=w_r(t_r-τ_k)w_a(t_a-t₀)exp[j2πf₀(t_r-τ_k)]exp[jπγ(t_r-τ_k)²]

Wherein, k=1,2 ..., K, K represent reception antenna number, t_rRepresent distance to fast time, t_aThe orientation slow time is represented, w_r() represents echo-signal distance to time window function, w_a() represents echo-signal orientation time window function, t₀Represent fortune At the center hold moment of moving-target, j represents imaginary unit, f₀Transmission signal carrier frequency is represented, γ represents transmission signal frequency modulation rate, τ_k Represent k-th time delay of antenna, τ_k=2R_k(t_a)/c, c represent propagation velocity of electromagnetic wave, R_k(t_a) represent t_aK-th of moment The distance between antenna and moving target,

R₀Represent that image scene center is flat with hypersonic Minimum distance between platform, v_rRepresent the radial velocity of moving target, v_aThe tangential velocity of moving target is represented, v represents ultrasound high Fast platform movement velocity, d_kRepresent the relative distance of k-th antenna and the 1st antenna, d_k=(k-1) d, d represent two neighboring day The relative distance of line；

Determine frequency domain reference signal H_r(f_r)=exp [j π (f₀+f_r)²/ γ], and using frequency domain reference signal to k-th reception day Line carries out pulse compression apart from frequency domain echo signal, obtain k-th reception antenna apart from frequency domain-orientation time domain echo-signal s_k(f_r,t_a) be：

s_k(f_r,t_a)=FFT_r[s_k(t_r,t_a)]×H_r(f_r)

=W_r(f_r)w_a(t_a-t₀)exp(-j2π(f₀+f_r)τ_k)

Wherein, f_rRepresent frequency of distance, FFT_r[] represents the FFT FFT operations of fast time dimension, W_r() represents Echo-signal is apart from frequency domain window function.

3. a kind of hypersonic platform clutter recognition according to claim 2 and motive target imaging method, its feature exist In step 2 is specially：

Oblique wave filter is removed for H in the orientation for constructing k-th reception antenna_a,k(f_r,t_a)：

$H_{a,k}(f_r,t_a)=\exp \left(j2\mathrm{\π}\frac{(f_0+f_r){({\mathrm{vt}}_a+d_k)}^2}{{\mathrm{cR}}_0}\right)$

To k-th reception antenna apart from frequency domain-orientation time domain echo-signal s_k(f_r,t_a) as orientation, contracting of going to barocline is processed, and according to The inverse Fourier transform of the secondary Fourier transformation for carrying out slow time dimension and fast time dimension, obtain k-th distance domain of reception antenna- The echo-signal s of Azimuth Compression frequency domain_k(t_r,f_a)：

s_k(t_r,f_a)=IFFT_r[FFT_a[s_k(f_r,t_a)×H_a,k(f_r,t_a)]]

=w_r(t_r-2R₀/c)W_a(f_a+2v_r/λ-2v²t₀/λR₀)

exp(-j4πR₀/λ)exp[-j2π(f_a+2v_r/λ)d_k/v]

Wherein, v_rThe radial velocity of moving target is represented, λ represents radar emission signal carrier frequency, FFT_a[] represents slow time dimension FFT is operated, IFFT_r[] represents the IFFT operations of fast time dimension, W_a() represents echo-signal orientation frequency domain window function, f_aTable Show orientation frequency.

4. a kind of hypersonic platform clutter recognition according to claim 3 and motive target imaging method, its feature exist In step 3 is specially：

K=1,2 ..., K are made, so as to respectively obtain the K echo-signal s of the distance domain of reception antenna-Azimuth Compression frequency domain₁ (t_r,f_a),s₂(t_r,f_a),…,s_K(t_r,f_a), the distance domain-Azimuth Compression frequency domain of the K reception antenna that then will be obtained is returned Ripple signal s₁(t_r,f_a),s₂(t_r,f_a),…,s_K(t_r,f_a) arranged in sequence, obtain echo-signal matrix s (t_r,f_a)= [s₁(t_r,f_a),s₂(t_r,f_a),…,s_K(t_r,f_a)]^T, wherein, subscript T represents that transposition is operated, f_aRepresent orientation frequency.

5. a kind of hypersonic platform clutter recognition according to claim 4 and motive target imaging method, its feature exist In step 4 specifically includes following sub-step：

(4a) sets the maximum estimated value v of moving target radial velocity_{r_range}V is spaced with rough estimate_{r_step}, and obtain needing slightly Total degree P=ceil (the v for slightly searching for_{r_range}/v_{r_step}), wherein ceil () represents the number operation that rounds up；

(4b) initialization iterations p=1；

(4c) carries out first step rough estimate to the radial velocity of moving target, obtains velocity estimation median v_{r_temp}=- v_{r_range}/2+p×v_{r_step}；

(4d) is if p<P, then make the value of p plus 1, and returns to sub-step (4c), otherwise to all velocity estimation medians for obtaining, asks Take each velocity estimation median and distinguish corresponding moving target energy；

(4e) selects to cause the velocity estimation median that moving target energy is maximum, used as the first step of moving target radial velocity Rough estimate value v_r0, i.e.,WhereinRepresent corresponding during acquisition moving target Energy maximum value Velocity estimation median v_{r_temp}；

(4f) tries to achieve moving target steering vectorFor：

$a_{T,v_{r0}}\left(f_a\right)={\left[\begin{array}{ccc}\exp (-j2\mathrm{\&pi;}(f_a+2v_{r0}/\mathrm{\&lambda;})d_1/v)& \mathrm{...}& \exp (-j2\mathrm{\&pi;}(f_a+2v_{r0}/\mathrm{\&lambda;})d_K/v)\end{array}\right]}^T$

(4g) tries to achieve Clutter steering vector a_C(f_a) be：

a_C(f_a)=[exp (- j2 π f_ad₁/v)…exp(-j2πf_ad_K/v)]^T。

6. a kind of hypersonic platform clutter recognition according to claim 5 and motive target imaging method, its feature exist In step 5 specifically includes following sub-step：

(5a) is according to the echo-signal matrix s (t_r,f_a), it is calculated covariance matrix R (f_a)=E [s (t_r,f_a)s^H(t_r, f_a)], wherein E [] is represented and is taken desired operation, and subscript H represents conjugate transposition；

(5b) is according to optimization problem：

$\left\{\begin{array}{cc}\underset{w_{v0}}{min}& w_{v_{r0}}^H\left(f_a\right)R\left(f_a\right)w_{v_{r0}}\left(f_a\right)\\ s.t.& w_{v_{r0}}^H\left(f_a\right)a_{T,v_{r0}}\left(f_a\right)=1\end{array}\right.$

Optimal weight vector coefficient required for trying to achieve clutter recognitionFor：

$w_{v_{r0}}\left(f_a\right)=\frac{R^{-1}\left(f_a\right)a_{T,v_{r0}}\left(f_a\right)}{a_{T,v_{r0}}^H\left(f_a\right)R^{-1}\left(f_a\right)a_{T,v_{r0}}\left(f_a\right)}$

WhereinCorresponding optimal weight vector coefficient when representing acquisition minimum value

(5c) is by the optimal weight vector coefficientWith the echo-signal matrix s (t_r,f_a) be multiplied, obtain corresponding miscellaneous Moving Target Return data after ripple suppressionFor：

$\begin{array}{c}{s}_{v_{r0}}(t_r,f_a)=s(t_r,f_a)\&times;w_{v_{r0}}\left(f_a\right)\\ =w_r(t_r-2R_0/c)W_a(f_a+2v_r/\mathrm{\&lambda;}-2v^2{t}_0/{\mathrm{\&lambda;R}}_0)\exp (-j4{\mathrm{\&pi;R}}_0/\mathrm{\&lambda;})\end{array}.$

7. a kind of hypersonic platform clutter recognition according to claim 6 and motive target imaging method, its feature exist In step 6 specifically includes following sub-step：

Construct rough radial velocity penalty functionFor：

$H_{v_{r0}}(f_r,t_a)=\exp \left(j4\mathrm{\&pi;}\right(f_r+f_0)v_{r0}{t}_a/c);$

Obtain the two-dimensional time-domain echo-signal of moving targetFor：

$\begin{array}{c}{s}_{v_{r0}}(t_r,t_a)={\mathrm{IFFT}}_r\&lsqb;{\mathrm{IFFT}}_a\&lsqb;{\mathrm{FFT}}_r\&lsqb;s_{v_{r0}}(t_r,f_a)\&rsqb;\&rsqb;\&times;H_{v_{r0}}(f_r,t_a)\&rsqb;\\ =w_r(t_r-2R_0/c)w_a(t_a-t_0)\\ \exp (-j4{\mathrm{\&pi;R}}_0/\mathrm{\&lambda;})\exp (-j4{\mathrm{\&pi;v}}_{r\_res}{t}_a/\mathrm{\&lambda;})\exp (j4{\mathrm{\&pi;v}}^2{t}_0{t}_a/{\mathrm{\&lambda;R}}_0)\end{array},$

Wherein, IFFT_a[] represents the IFFT operations of slow time dimension, v_{r_res}Represent to rough radial velocity v_r0After compensating Residual radial velocity, v_{r_res}=v_r-v_r0。

8. a kind of hypersonic platform clutter recognition according to claim 7 and motive target imaging method, its feature exist In step 7 is specially：

It is [v to set and the hunting zone of second step precise search is carried out to the radial velocity of moving target_r0-v_{r_step}/2,v_r0+ v_{r_step}/ 2] Radon conversion, and in the hunting zone is carried out, residual radial velocity v is tried to achieve_{r_res}, and obtain moving target footpath To the fine estimation v of speed_{r_est}=v_r0+v_{r_res}。

9. a kind of hypersonic platform clutter recognition according to claim 8 and motive target imaging method, its feature exist In in step 8：

Obtain the Moving Target Return signal apart from frequency domain-orientation time domainFor：

$\begin{array}{c}{s}_{v_{r0}}(f_r,t_a)={\mathrm{FFT}}_r\&lsqb;s_{v_{r0}}(t_r,t_a)\&rsqb;\\ =W_r\left(f_r\right)w_a(t_a-t_0)\exp (-j4\mathrm{\&pi;}(f_r+f_0)R_0/c)\\ \exp (-j4\mathrm{\&pi;}(f_r+f_0)v_{r\_res}{t}_a/c)\exp \left(j4{\mathrm{\&pi;v}}^2\right(f_r+f_0)t_0{t}_a/{\mathrm{cR}}_0)\end{array};$

Construction residual radial velocity penalty functionFor：

$H_{v_{r\_res}}(f_r,t_a)=\exp \left(j4\mathrm{\&pi;}\right(f_r+f_0)v_{r\_res}{t}_a/c);$

Echo-signal s (f after accurately being compensated_r,t_a) be：

$\begin{array}{c}s(f_r,t_a)=s_{v_{r0}}(f_r,t_a)\&times;H_{v_{r\_res}}(f_r,t_a)\\ =W_r\left(f_r\right)w_a(t_a-t_0)\exp (-j4\mathrm{\&pi;}(f_r+f_0)R_0/c)\\ \exp \left(j4{\mathrm{\&pi;v}}^2\right(f_r+f_0)t_0{t}_a/{\mathrm{cR}}_0)\end{array}.$

10. a kind of hypersonic platform clutter recognition according to claim 9 and motive target imaging method, its feature exist In, in step 9,

The moving target signal s (t for being focused on_r,f_a) be：

$\begin{array}{c}s(t_r,f_a)={\mathrm{IFFT}}_r\&lsqb;{\mathrm{FFT}}_a\&lsqb;s(f_r,t_a)\&rsqb;\&rsqb;\\ =w_r(t_r-2R_0/c)W_a(f_a-2v^2{t}_0/{\mathrm{\&lambda;R}}_0)\exp (-j4{\mathrm{\&pi;R}}_0/\mathrm{\&lambda;})\end{array}.$