CN102967859B - Forward-looking scanning radar imaging method - Google Patents

Abstract

The invention discloses a forward-looking scanning radar imaging method. The method comprise the steps of initializing imaging system parameters; performing range pulse compression on echo data; subjecting a radar right forward-looking area to super-resolution imaging processing; performing back projection imaging processing on a large-azimuth area; and splicing imaging results of the two areas. According to the forward-looking scanning radar imaging method, an ill-posed problem regularization method is utilized, and accordingly, the azimuth resolution is improved, and a back projection algorithm is combined to improve the azimuth resolution of the large-azimuth area. The two imaging results are spliced into a complete scene image, so that the forward-looking scanning radar imaging scene range is expanded, and not only the defect that synthetic aperture radars cannot perform forward-looking imaging is overcome, but also the problem that azimuth imaging scene ranges of prior forward-looking scanning radars are small is solved.

Description

A kind of forward sight scanning radar formation method

Technical field

The invention belongs to Radar Signal Processing Technology field, particularly the formation method in forward sight scanning radar (Forward-Looking Scanning Radar) technology.

Background technology

Microwave Imaging Technique has the feature of round-the-clock, all weather operations as a kind of Aeronautics and Astronautics remote sensing of active, in fields such as geological mapping, disaster monitoring, military surveillances, have a wide range of applications, become at present high resolving power earth observation and global resources and managed one of most important means.But the restriction due to working system own, existing synthetic-aperture radar (Synthetic Aperture Radar, SAR) can not realize forward vision areas orientation to high-resolution imaging, thus make SAR aircraft forward sight over the ground, the aspect such as independent landing, cargo assault, Missile Terminal Guidance can not fully play effect.

Forward sight scanning radar is a kind of radar forward sight imaging technique based on ill-posed problem Regularization Theory, overcome the problem that SAR exists forward sight blind area.In Texas tower motion process, antenna scans forward sight imaging region, by launching large bandwidth signal, form distance to high-resolution, orientation after motion compensation is modeled as to the convolution model of ground scatter point and antenna radiation pattern to echo sequence, finally utilize ill-posed problem regularization method to estimate scene information, complete forward vision areas orientation to high-resolution imaging.

Along with imaging scene position angle increases, echo Doppler coherence strengthens, and causes the convolution model of the larger area echo data in position angle to be affected, and has limited forward sight scanning radar imaging scene domain.At document " Richards M.; Morris C.; Hayes M.; Iterative enhancement of noncoherent radar data; IEEE International Conference on Acoustics Speech and Signal Processing; 1929-1932,1986 " in, point out; forward sight scanning radar is during to the larger regional imaging in position angle; ill-posed problem regularization method is more responsive to Doppler effect; can affect algorithm performance, document does not have to propose to be expanded into the method for picture scene domain.Within the scope of large scene, realize the imaging of radar forward sight, can allow aircraft bring into play better performance at aspects such as battle reconnaissance supervision, cargo assault and seismic disaster reliefs.At document " Malenke T., Oelgart T., Rieck W., W-band-radar system in a dual-mode seeker for autonomous target detection, European Conference on Synthetic Aperture Radar, 2002 " in, propose to use Doppler beam sharpening (DBS, Doppler Beam Sharpening) technology increases forward sight imaging scene domain, forward vision areas Doppler changes slowly, adopt DBS can not obtain good forward sight imaging results, between positive forward sight super-resolution processing region and the effective processing region of DBS, imaging results precision is still very poor.

Summary of the invention

The object of the invention is the above-mentioned defect existing when the forward sight scanning radar imaging processing in order to solve existing method, proposed a kind of forward sight scanning radar formation method.

Content of the present invention for convenience of description, first makes an explanation to following term:

Term 1: forward sight scanning radar

Forward sight scanning radar refers in Texas tower motion process, utilizes antenna to scan forward sight imaging region, thereby echo data is carried out to a kind of sensing system that signal processing is embodied as picture.Radar system signal model is referring to document " Li D.Y., Huang Y.L, Yang J.Y; Motion platform forward-looking real-beam radar echo modeling; IEEE CIE International Conference on Radar, 1370-1373,2011 ".

Term 2: forward sight imaging side parallactic angle

Forward sight imaging side parallactic angle refers to Texas tower heading is decided to be to 0 °, and imageable target and aircraft line depart from the angle of heading, and position angle, heading left side is for negative, and position angle, right side is for just.

Term 3: radar angle super-resolution algorithm (Radar angle superresolution algorithm)

Radar angle super-resolution algorithm is a kind of radar imagery algorithm based on ill-posed problem Regularization Theory.Forward sight scanning radar orientation can be modeled as the convolution model of original scene and radar directional pattern function to echo sequence, by ill-posed problem regularization method, can estimate original scene.This method breaks through the restriction of real aperture azimuthal resolution, has realized radar angle super-resolution.

Term 4: back-projection algorithm (Back Projection, BP)

Back-projection algorithm is from the auxiliary tomography technology of medical imaging Computer, this algorithm utilizes projection slice theorem (Projection-slice theorem), radar echo signal after different visual angles demodulation is modeled as to a section of original scene two-dimensional Fourier transform, by back-projection algorithm, avoid the complex calculation in direct two-dimentional inverse Fourier transform, obtain the accurate estimation of original scene, realize high azimuth resolution imaging processing, specifically referring to document " Munson D.C., O ' Brien J.D., Jenkins W.K., A tomography formulation of spotlight-mode synthetic aperature radar, Proceedings of the IEEE, vol71, no8, 917-925, 1983 ".

Technical scheme of the present invention is: a kind of forward sight scanning radar formation method, specifically comprises the steps:

Step 1: imaging system parameter initialization,

Specifically comprise following parameter: platform speed, is designated as V; Antenna elevation angle, is designated as

podium level, is designated as h; Transmitted signal carrier frequency, is designated as f ₀; Pulse width, is designated as T _r;

Orientation time arrow is designated as t=[-PRIN _a/ 2 ,-PRI (N _a/ 2-1) ..., PRI (N _a/ 2-1)], wherein, PRI is pulse-recurrence time, N _afor target echo orientation is to sampling number; Distance Time vector is designated as: τ=[1/f _sn _f/ 2 ,-1/f _s(N _f/ 2-1) ..., 1/f _s(N _f/ 2-1)], wherein, f _sfor distance is to sampling rate, N _ffor target echo distance is to sampling number;

Objective plane point target apart from history is

wherein, R ₀for the orientation time is the initial oblique distance of 0 moment antenna and point target, θ ₀be 0 position angle corresponding to moment point target;

Step 2: echo data is carried out to distance to pulse compression,

Target echo expression formula is:

$\begin{array}{c}s(\mathrm{\&tau;},t;x,y)=\mathrm{\&sigma;}(x,y)w_a\left[\frac{t-t_{{\mathrm{\&theta;}}_0}}{T_{\mathrm{beta}}}\right]\mathrm{rect}\left[\frac{\mathrm{\&tau;}-{\mathrm{\&tau;}}_d(t;x,y)}{T_r}\right]\\ *\exp \left\{\mathrm{j\&pi;}{K}_r{[\mathrm{\&tau;}-{\mathrm{\&tau;}}_d(t;x,y)]}^2\right\}*\exp \{-\mathrm{<figure-callout\; id="4"\; label="j"\; filenames="HDA00002398914200031.png,HDA00002398914200032.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{4\mathrm{\&pi;}}{\mathrm{\&lambda;}}R(t;x,y)\}\end{array}$

Wherein, σ (x, y) is reflection coefficient,

be round trip echo delay, c is the light velocity, w _a[] represents slow time domain window function, represents that orientation is to the modulation of antenna radiation pattern function, window width T _betarepresentative point object beam residence time,

for azimuth angle theta ₀the corresponding orientation moment, rect[] represent fast time domain window function, window width is T _r, K _rfor the frequency modulation rate that transmits, λ is carrier wavelength;

To forward sight scanning radar echo data s (τ, t; X, y) carry out distance to pulse compression, after pulse pressure, data are expressed as s ₁(τ, t; X, y);

Preset for determining the first party parallactic angle θ of super-resolution imaging processing region _αwith the second party parallactic angle θ for definite rear orientation projection's imaging processing region _β, meet θ _βbe greater than θ _α;

Step 3: the positive forward vision areas of radar is carried out to super-resolution imaging processing,

In step 2 distance to the data s after process of pulse-compression ₁(τ, y; X, y) in, be positioned at-θ of position angle taken out _α～θ _αwithin data, be decided to be radar angle super-resolution processing region, data are expressed as:

$s_2(\mathrm{\&tau;},t;x,y)=\mathrm{\&sigma;}(x,y)w_a\left[\frac{{t-t}_{{\mathrm{\&theta;}}_0}}{T_{\mathrm{beta}}}\right]\sin c\left\{B\right[\mathrm{\&tau;}-{\mathrm{\&tau;}}_d(t;x,y)\left]\right\}*\exp \{-\mathrm{<figure-callout\; id="4"\; label="j"\; filenames="HDA00002398914200031.png,HDA00002398914200032.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{4\mathrm{\&pi;}}{\mathrm{\&lambda;}}R(t;x,y)\}$

Wherein, be respectively position angle-θ _α, θ _αconstantly, B is transmitted signal bandwidth in corresponding orientation;

Historical R (the t of point target oblique distance; X, y) retain after Taylor series expansion once, can obtain

oblique distance history is approximately to R (t; X, y) ≈ R ₀-Vt; Utilize the oblique distance after being similar to historical, at super-resolution treatment region data s ₂(τ, t; X, y) in, the time variable of adjusting the distance τ passes through substitution of variable carry out change of scale, eliminate the range walk that platform motion produces, complete motion compensation, the data after change of scale are expressed as:

$\begin{array}{c}{s}_3(\mathrm{\&tau;},t;x,y)=s_2(\mathrm{\&tau;}-\frac{2\mathrm{Vt}}{c},t;x,y)\\ =\mathrm{\&sigma;}(x,y)w_a\left[\frac{{t-t}_{{\mathrm{\&theta;}}_0}}{T_{\mathrm{beta}}}\right]\sin c\left\{B\right[\mathrm{\&tau;}-\frac{{2R}_0}{c}\left]\right\}*\exp \{-\mathrm{<figure-callout\; id="4"\; label="j"\; filenames="HDA00002398914200031.png,HDA00002398914200032.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{4\mathrm{\&pi;}}{\mathrm{\&lambda;}}R(t;x,y)\}\end{array}$

Antenna radiation pattern function f _antenas with reference to function, to data s ₃(τ, t; X, y) carry out ill-posed problem Regularization, realize data s ₃(τ, t; X, y) angle super-resolution, imaging results is designated as to s ₄(τ, t; X, y);

Step 4: utilize back-projection algorithm to carry out imaging processing to compare great region, position angle,

In step 2 distance to the data s after process of pulse-compression ₁(τ, y; X, y) in, be positioned at-θ of position angle taken out _β～-θ _α, θ _α～θ _βwithin data, be decided to be rear orientation projection's treatment region, data are expressed as:

$s_5(\mathrm{\&tau;},t;x,y)=\mathrm{\&sigma;}(x,y)w_a\left[\frac{{t-t}_{{\mathrm{\&theta;}}_0}}{T_{\mathrm{beta}}}\right]\sin c\left\{B\right[\mathrm{\&tau;}-{\mathrm{\&tau;}}_d(t;x,y)\left]\right\}*\exp \{-\mathrm{<figure-callout\; id="4"\; label="j"\; filenames="HDA00002398914200031.png,HDA00002398914200032.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{4\mathrm{\&pi;}}{\mathrm{\&lambda;}}R(t;x,y)\}$

Wherein,

be respectively position angle-θ _β, θ _βcorresponding orientation constantly;

The positional information of system log (SYSLOG) while moving according to Texas tower, calculates any point target on objective plane, arrives the distance of Texas tower in antenna beam irradiation time

for wave beam residence time vector corresponding to point target; According to calculate round trip time delay utilize t (x, y) structure phase compensating factor Φ (x, y)=exp{-j2 π f ₀t (x, y) }, f ₀for carrier frequency;

To the treatment region data s of rear orientation projection ₅(τ, t; X, y) carry out distance to interpolation, by the data s' after interpolation ₅(τ, t; X, y) and phase compensating factor by formula $s_6(\mathrm{\&tau;},t;x.y)={\&Integral;}_{t_{{\mathrm{\&theta;}}_0}}{s}_5^{\&prime;}(\mathrm{\&tau;},t;x,y)\mathrm{\&Phi;}(x,y){\mathrm{dt}}_{{\mathrm{\&theta;}}_0}$ Carry out coherent accumulation, obtain the accurate estimation of imaging scene every bit target (x, y), realize data s ₅(τ, t; X, y) rear orientation projection's imaging processing, imaging results is designated as s ₆(τ, t; X, y);

Step 5: two regional imaging result splicings are processed,

Imaging results s after step 3 super-resolution is processed ₄(τ, t; X, y) and the imaging results s of step 4 rear orientation projection after processing ₆(τ, t; X, y) do splicing processing, the data after splicing is processed are the final imaging results of forward sight scanning radar, are designated as s ₇(τ, t; X, y).

Beneficial effect of the present invention: forward sight scanning radar formation method of the present invention adopts ill-posed problem regularization method to improve azimuthal resolution in the positive forward vision areas of radar, and improve compare great region, position angle azimuthal resolution in conjunction with back-projection algorithm, two parts imaging results is spliced into a complete scene image, has expanded forward sight scanning radar imaging scene domain.Method of the present invention has not only overcome the weakness that synthetic-aperture radar can not forward sight imaging, and has solved the little problem of existing forward sight scanning radar scene area in azimuth dimension.Method of the present invention can, in the larger imaging scene domain of forward vision areas, realize high azimuth resolution imaging processing.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of forward sight scanning radar formation method of the present invention.

Fig. 2 is the forward sight scanning radar system construction drawing that the specific embodiment of the invention adopts.

Fig. 3 is the forward sight scanning radar system parameter table that the specific embodiment of the invention adopts.

Fig. 4 is the target scene arrangenent diagram adopting in the specific embodiment of the invention, and dotted line is the region separation line of super-resolution imaging processing and rear orientation projection's imaging processing.

Fig. 5 be in the specific embodiment of the invention in Fig. 4 super-resolution imaging processing region, 9 point targets are carried out the result schematic diagram of imaging.

Fig. 6 is that in specific embodiment of the invention Zhong Dui Fig. 4 rear orientation projection's imaging processing region, 12 point targets are carried out the result schematic diagram of imaging.

Fig. 7 is the final imaging results after imaging data splicing in Fig. 5 and Fig. 6 being processed in the specific embodiment of the invention.

Embodiment

The present invention mainly adopts the method for emulation experiment to verify, institute in steps, conclusion all on Matlab2010 checking correct.Below in conjunction with the drawings and specific embodiments, the inventive method is further elaborated.

As shown in Figure 1, detailed process is as follows for the schematic flow sheet of forward sight scanning radar formation method of the present invention:

Step 1: imaging system parameter initialization.

As shown in Figure 2, it is true origin that system coordinate system be take the Ground Point of Texas tower below to the imaging geometry mode chart that the present embodiment adopts, and platform moves along y axle, and x axle is for cutting flight path direction, and z axle is vertical ground direction.According to the listed data initialization imaging system of Fig. 3 parameter.

As shown in Figure 4, the black round dot in figure is for being arranged on ground 3 * 7 totally 21 point targets for the target scene that the present embodiment adopts.These 21 points are along 3 °, θ direction of principal axis (forward sight imaging side parallactic angle) interval, along 200 meters, Y direction (along flight path) interval.Texas tower zero constantly position coordinates is (0,0,5000) m, and target scene center o point coordinate is (0,10000,0) m.In scene, the position coordinates of any point target is designated as P (x, y).

Structure orientation time arrow t=[-PRIN _a/ 2 ,-PRI (N _a/ 2-1) ..., PRI (N _a/ 2-1)], wherein, PRI is pulse-recurrence time, N _afor target echo orientation is to sampling number.Structure Distance Time vector τ=[1/f _sn _f/ 2 ,-1/f _s(N _f/ 2-1) ..., 1/f _s(N _f/ 2-1)], wherein, f _sfor distance is to sampling rate, N _ffor target echo distance is to sampling number.

Step 2: echo data is carried out to distance to pulse compression.

According to Texas tower in step 1 and point target coordinate position, utilize Matlab to simulate point target echo data s (τ, t; X, y).

Here distance specifically adopts following process to pulse compression:

According to the frequency modulation rate K that transmits _r, distance is to reference time τ _ref, structure distance is to pulse compression reference signal utilize matched filtering, forward sight scanning radar echo data is carried out to distance to pulse compression, the data after pulse pressure are expressed as s ₁(τ, t; X, y):

$s_1(\mathrm{\&tau;},t;x,y)=\mathrm{\&sigma;}(x,y)w_a\left[\frac{{t-t}_{{\mathrm{\&theta;}}_0}}{T_{\mathrm{beta}}}\right]\sin c\left\{B\right[\mathrm{\&tau;}-{\mathrm{\&tau;}}_d(t;x,y)\left]\right\}*\exp \{-\mathrm{<figure-callout\; id="4"\; label="j"\; filenames="HDA00002398914200031.png,HDA00002398914200032.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{4\mathrm{\&pi;}}{\mathrm{\&lambda;}}R(t;x,y)\}.$

Wherein, sinc{} is distance response function, and B is transmitted signal bandwidth.

Preset for determining the first party parallactic angle θ of super-resolution imaging processing region _αwith the second party parallactic angle θ for definite rear orientation projection's imaging processing region _β, meet θ _βbe greater than θ _α.

Here θ _αand θ _βcan determine according to antenna scan angle information and systematic parameter, generally according to experience, choose, the process of choosing that it is concrete no longer describes in detail.In the present embodiment, θ _αget 5 °, θ _βget 10 °.

Step 3: the positive forward vision areas of radar is carried out to super-resolution imaging processing.

The antenna scan angle information obtaining during according to emulation, the present embodiment in step 2 distance to the data s after process of pulse-compression ₁(τ, t; X, y) in, take out position angle and be positioned at the data within-5 °～5 °, be decided to be radar angle super-resolution imaging treatment region, data are designated as s ₂(τ, t; X, y).

Historical R (the t of point target oblique distance; X, y) retain after Taylor series expansion once, can obtain

oblique distance history is approximately to R (t; X, y) ≈ r ₀-Vt.Utilize t ₀=2*Vt/c, as Range Walk Correction amount, constructs phase compensating factor Φ _rcm=exp{2 π f _st ₀.

In distance to data s ₂(τ, t; X, y) carry out change of scale, eliminate the range walk that platform motion produces, complete motion compensation.During concrete enforcement, to super-resolution imaging treatment region data s ₂(τ, t; X, y) carry out distance to Fourier transform, conjugate multiplication phase compensating factor Φ _rcmafter, to data, along distance, to carrying out Fourier inversion, can complete Range Walk Correction, the data after motion compensation are designated as to s ₃(τ, t; X, y).

Antenna radiation pattern function f _antenas with reference to function, to data s ₃(τ, t; X, y) carry out ill-posed problem Regularization, realize data s ₃(τ, t; X, y) angle super-resolution, imaging results is designated as to s ₄(τ, t; X, y).Fig. 5 is the positive forward vision areas super-resolution imaging of radar result.

Step 4: utilize back-projection algorithm to carry out imaging processing to compare great region, position angle.

The antenna scan angle information obtaining during according to emulation, the present embodiment in step 2 distance to the data s after process of pulse-compression ₁(τ, t; X, y) in, to take out position angle and be positioned at-10 °～-5 °, the data within 5 °～10 °, are decided to be rear orientation projection's imaging processing district, and data are designated as s ₅(τ, t; X, y).

The positional information of system log (SYSLOG) while moving according to Texas tower, calculates any point target on objective plane, arrives the distance of Texas tower in antenna beam irradiation time

for wave beam residence time vector corresponding to point target.According to

calculate round trip time delay utilize t (x, y) structure phase compensating factor Φ (x, y)=exp{-j2 π f ₀t (x, y) }, f ₀for carrier frequency.

To the treatment region data s of rear orientation projection ₅(τ, t; X, y) carry out distance to interpolation, the interpolation here can be general interpolation method, the present embodiment adopts 8 sinc interpolation.By the data s' after interpolation ₅(τ, t; X, y) and phase compensating factor Φ (x, y) by formula

carry out coherent accumulation, obtain the accurate estimation of imaging scene every bit target (x, y), realize data s ₅(τ, t; X, y) rear orientation projection's imaging processing, imaging results is designated as to s ₆(τ, t; X, y).Fig. 6 is compare great region, position angle rear orientation projection imaging processing result.

Step 5: two regional imaging result splicings are processed.

Imaging results s after step 3 super-resolution is processed ₄(τ, t; X, y) and the imaging results s of step 4 rear orientation projection after processing ₆(τ, t; X, y) do splicing processing, the data after splicing is processed are the final imaging results of forward sight scanning radar, are designated as s ₇(τ, t; X, y).

In the present embodiment, specifically can adopt following splicing to process:

Imaging results s after step 3 super-resolution is processed ₄(τ, t; X, y) and the imaging results s of step 4 rear orientation projection after processing ₆(τ, t; X, y) make respectively normalized; Two-dimentional sinc function is used in docking region in two width imaging results, and single pixel weighted mean, on the respective pixel of lap position, the gray scale of feasible region merges, and guarantees the seamless spliced processing of image; Data after splicing is processed are the final imaging results of forward sight scanning radar, are designated as s ₇(τ, t; X, y).

Fig. 7 is the final imaging results schematic diagram that adopts the inventive method to obtain in embodiment.Can find out, the inventive method, in larger imaging scene domain, has realized forward sight scanning radar high azimuth resolution imaging processing.

Those of ordinary skill in the art will appreciate that, embodiment described here is in order to help reader understanding's principle of the present invention, should be understood to that protection scope of the present invention is not limited to such special statement and embodiment.Those of ordinary skill in the art can make various other various concrete distortion and combinations that do not depart from essence of the present invention according to these technology enlightenments disclosed by the invention, and these distortion and combination are still in protection scope of the present invention.

Claims (3)

1. a forward sight scanning radar formation method, specifically comprises the steps:

Step 1: imaging system parameter initialization,

Specifically comprise following parameter: platform speed, is designated as V; Antenna elevation angle, is designated as podium level, is designated as h; Transmitted signal carrier frequency, is designated as f ₀; Pulse width, is designated as T _r;

Orientation time arrow is designated as t=[-PRIN _a/ 2 ,-PRI (N _a/ 2-1) ..., PRI (N _a/ 2-1)], wherein, PRI is pulse-recurrence time, N _afor target echo orientation is to sampling number; Distance Time vector is designated as: τ=[1/f _sn _f/ 2 ,-1/f _s(N _f/ 2-1) ..., 1/f _s(N _f/ 2-1)], wherein, f _sfor distance is to sampling rate, N _ffor target echo distance is to sampling number;

Objective plane point target apart from history is

wherein, R ₀for the orientation time is the initial oblique distance of 0 moment antenna and point target, θ ₀be 0 position angle corresponding to moment point target;

Step 2: echo data is carried out to distance to pulse compression,

Target echo expression formula is:

Wherein, σ (x, y) is reflection coefficient,

be round trip echo delay, c is the light velocity, w _a[] represents slow time domain window function, represents that orientation is to the modulation of antenna radiation pattern function, window width T _betarepresentative point object beam residence time, for azimuth angle theta ₀the corresponding orientation moment, rect[] represent fast time domain window function, window width is T _r, K _rfor the frequency modulation rate that transmits, λ is carrier wavelength;

To forward sight scanning radar echo data s (τ, t; X, y) carry out distance to pulse compression, after pulse pressure, data are expressed as s ₁(τ, t; X, y);

Preset for determining the first party parallactic angle θ of super-resolution imaging processing region _αwith the second party parallactic angle θ for definite rear orientation projection's imaging processing region _β, meet θ _βbe greater than θ _α;

Step 3: the positive forward vision areas of radar is carried out to super-resolution imaging processing,

In step 2 distance to the data s after process of pulse-compression ₁(τ, y; X, y) in, be positioned at-θ of position angle taken out _α～θ _αwithin data, be decided to be radar angle super-resolution processing region, data are expressed as:

Wherein,

be respectively position angle-θ _α, θ _αconstantly, B is transmitted signal bandwidth in corresponding orientation;

Historical R (the t of point target oblique distance; X, y) retain after Taylor series expansion once, can obtain

oblique distance history is approximately to R (t; X, y) ≈ R ₀-Vt; Utilize the oblique distance after being similar to historical, at super-resolution treatment region data s ₂(τ, t; X, y) in, the time variable of adjusting the distance τ passes through substitution of variable carry out change of scale, eliminate the range walk that platform motion produces, complete motion compensation, the data after change of scale are expressed as:

Antenna radiation pattern function is as with reference to function, to data s ₃(τ, t; X, y) carry out ill-posed problem Regularization, realize data s ₃(τ, t; X, y) angle super-resolution, imaging results is designated as to s ₄(τ, t; X, y);

Step 4: utilize back-projection algorithm to carry out imaging processing to compare great region, position angle,

In step 2 distance to the data s after process of pulse-compression ₁(τ, y; X, y) in, be positioned at-θ of position angle taken out _β～-θ _α, θ _α～θ _βwithin data, be decided to be rear orientation projection's treatment region, data are expressed as:

Wherein,

be respectively position angle-θ _β, θ _βcorresponding orientation constantly;

The positional information of system log (SYSLOG) while moving according to Texas tower, calculates any point target on objective plane, arrives the distance of Texas tower in antenna beam irradiation time

for wave beam residence time vector corresponding to point target; According to

calculate round trip time delay

utilize t (x, y) structure phase compensating factor Φ (x, y)=exp{-j2 π f ₀t (x, y) }, f ₀for carrier frequency;

To the treatment region data s of rear orientation projection ₅(τ, t; X, y) carry out distance to interpolation, by the data s' after interpolation ₅(τ, t; X, y) and phase compensating factor by formula

carry out coherent accumulation, obtain the accurate estimation of imaging scene every bit target (x, y), realize data s ₅(τ, t; X, y) rear orientation projection's imaging processing, imaging results is designated as s ₆(τ, t; X, y);

Step 5: two regional imaging result splicings are processed,

Imaging results s after step 3 super-resolution is processed ₄(τ, t; X, y) and the imaging results s of step 4 rear orientation projection after processing ₆(τ, t; X, y) do splicing processing, the data after splicing is processed are the final imaging results of forward sight scanning radar, are designated as s ₇(τ, t; X, y).

2. forward sight scanning radar formation method according to claim 1, is characterized in that, described in step 2 to forward sight scanning radar echo data s (τ, t; X, y) carry out distance and adopt following process to pulse compression is concrete:

According to the frequency modulation rate K that transmits _r, distance is to reference time τ _ref, structure distance is to pulse compression reference signal

, utilize matched filtering, forward sight scanning radar echo data is carried out to distance to pulse compression, the data after pulse pressure are expressed as s ₁(τ, t; X, y):

Wherein, sinc{} is distance response function.

3. forward sight scanning radar formation method according to claim 1 and 2, is characterized in that, it is as follows that detailed process is processed in the splicing described in step 5:

Imaging results s after step 3 super-resolution is processed ₄(τ, t; X, y) and the imaging results s of step 4 rear orientation projection after processing ₆(τ, t; X, y) make respectively normalized; Two-dimentional sinc function is used in docking region in two width imaging results, and single pixel weighted mean, on the respective pixel of lap position, the gray scale of feasible region merges, and the data after splicing is processed are the final imaging results of forward sight scanning radar, are designated as s ₇(τ, t; X, y).

Images