【雷达通信】基于Omiga－K算法SAR回波生成和成像含Matlab源码
1 简介
基于Omiga－K算法SAR回波生成和成像含Matlab源码
2 部分代码
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Omiga－K算法版本2%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%clear all;clc;c=299792458; %light speedload sarecho.mat;fc=Head(1);B=Head(2);Tp=Head(3);fs=Head(4);V=Head(5);PRF=Head(6);dx=Head(7);dy=Head(8);Res_r=Head(9);Res_a=Head(10);theta=Head(11);Rg0=Head(12);Rang_Wath=Head(13);Range_Swath=Head(14);Azimuth_Swath=Head(15);h=Head(16);Rmin=Head(17);Src=Head(18);Rmax=Head(19);Azimuth_StartNum=Head(20);Azimuth_EndNum=Head(21);rawdatawidth=Head(22);slicelen=Head(23);lamda = c/fc;K=B/Tp; %调频率%%%%%%%%%%%%%%%%%OmigaK算法%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%cj = sqrt(-1);% dt=1/fs;delaymin=2*Rmin/c-Tp/2; %距离波门起始时刻% %%%%%%%%%%%%%%%%%%%%%%%%%%Omiga K算法%%%%%%%%%%%%%%%%%%%%%%%%%%%%%Na=rawdatawidth;Nr=slicelen;T=Tp;fx0=round(Na/2);ft0=round(Nr/2);fx=([1:Na]-fx0)/(Na-1)*PRF; %Doppler frequencyfr=(([1:Nr]-ft0)/(Nr-1)*fs); %距离向频率%距离压缩N = round(fs*Tp);figure;imagesc(abs(sr));title('回波仿真结果');% sfa=fftshift(fft(sr),1);% sfa2 = fftshift(fft(sfa,[],2),2);sfa2 =fftshift(fft2(fftshift(sr)));H_Range_Com=exp(cj*pi*fr.^2/K).'*ones(1,Na); %距离向压缩因子H_PHASE = exp(cj*4*pi*Src/c*sqrt((fr.'+fc).^2*ones(1,Na)-ones(Nr,1)*(c*fx/2/V).^2));%参考距离中心处的方位向聚焦因子Hshift = exp(-cj*Src*4*pi*(fr+fc)/c).'*ones(1,Na); %将图像时域移动到距离中心sfa2 = sfa2.*H_Range_Com.*Hshift.*H_PHASE;figure;imagesc(abs(sfa2));%%Stolt插值,根据非均匀值插出均匀值% Nr2=Nr-N;ft0=round(Nr/2);% fr=fftshift(fr); %距离向频率P=1;%8点sinc插值Stolt_krkx=zeros(Nr,Na);%初始化dfr=fs/(Nr-1);%频域间隔Stolt_krkx = sqrt((fr.'+fc).^2*ones(1,Na)+ones(Nr,1)*(c*fx/2/V).^2)-fc;delta_fr = Stolt_krkx-fr.'*ones(1,Na);Kr=fix(delta_fr/dfr);%linear interpolator%8 point SINC interpolatorNd = Kr(1,end)F = [sfa2;zeros(Nd+P,Na)]; %回波数据stolt_sfa2 = zeros(Nr,Na);for i=P+1:Nrfor j=1:NaT=Kr(i,j)+(-P:P);f=F(T+i,j).';% stolt_sfa2(i,j)=sum(f.*sinc(delta_fr(i,j)/dfr-T));stolt_sfa2(i,j)=sinc(delta_fr(i,j)/dfr-T)*F(T+i,j);endendfigure;imagesc(abs(stolt_sfa2));%H_phase1 = exp(cj*Src*sqrt((kr+krc).^2*ones(1,Na)-ones(Nr2,1)*kx.^2));%%聚焦因子stolt_sfa2 = stolt_sfa2;%.*H_phase1;sfa3 =fftshift(ifft2(stolt_sfa2));figure;imagesc(abs(sfa3));[pm,pn] = plotsection(sfa3.');% Nt =pn;kp_a = 2;deltA = V/PRF*kp_a;deltR = c/2/fs;indexa =[1:Na].';indext = [1:Nr].';Mr = 16;Ma = round(Mr*kp_a);%幅度量化dB图% my_plot(indexa(pm-Ma:kp_a:pm+Ma),indext(pn-Mr:pn+Mr),sfa3(pn-Mr:pn+Mr,pm-Ma:kp_a:pm+Ma),50);% xlabel('方位向(点数)');ylabel('距离向(点数)');title('Omiga-K成像结果幅度量化dB图');figure(8);%彩色等高线图contour(indext(pn-Mr:pn+Mr),indexa(pm-Ma:kp_a:pm+Ma),abs(sfa3(pn-Mr:pn+Mr,pm-Ma:kp_a:pm+Ma).'),40);colorbar;%T = sfa3(pn-Mr+1:pn+Mr,pm-Ma+1:pm+Ma);ft2= fft(T,[],1);T3= ifft(ft2,Mr*16,1);ft = fft(T3,[],2);T2 = ifft(ft,Ma*64,2);XA = linspace(indexa(pm-Ma+1),indexa(pm+Ma),Ma*64);XR = linspace(indext(pn-Mr+1),indext(pn+Mr),Mr*16);% my_plot(XA,XR,T2,50);colormap(gray);[pm2,pn2] = plotsection(T2.');
3 仿真结果
4 参考文献
[1]孙进平, 洪文, 柳重堪,等. 条带模式合成孔径雷达回波数据的聚束成像算法处理[J]. 航空学报, 2001.
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