rd算法.doc

%产生Stripmap SAR的回波clear allthetaT=0;%T平台波束斜视角thetaT=thetaT*pi/180;%radthetaR=0;%R平台波束斜视角thetaR=thetaR*pi/180;c=3e8;%光速fc=1.5e9;%载频lambda=c/fc;%波长%测绘带区域X0=200;%方位向-X0,X0Rtc=3000; Rrc=3000;Rc=(Rtc+Rrc)/2;R0=150;%距离向Rc-R0,Rc+R0%距离向(Range),r/t domainTr=1.5e-6;%LFM信号脉宽 1.5us (200m)Br=150e6; %LFM信号带宽 150MHzKr=Br/Tr; %调频斜率Nr=512;r=Rc+linspace(-R0,R0,Nr);t=2*r/c;%t域序列dt=R0*4/c/Nr;%采样周期f=linspace(-1/2/dt,1/2/dt,Nr);%f域序列%方位向(Azimuth,Cross-Range),x/u domainv=100;%SAR 平台速度Lsar=300;%合成孔径长度Na=1024;x=linspace(-X0,X0,Na);%u域序列u=x/v;du=2*X0/v/Na;fu=linspace(-1/2/du,1/2/du,Na);%fu域序列ftdc=v*sin(thetaT);ftdr=-(v*cos(thetaT)2/lambda/Rtc;frdc=v*sin(thetaR);frdr=-(v*cos(thetaR)2/lambda/Rrc;fdc=ftdc+frdc;%Doppler调频中心频率fdr=ftdr+frdr;%Doppler调频斜率%目标位置Ntar=3;%目标个数Ptar=Rrc,0,1 %距离向坐标,方位向坐标,sigma Rrc+50,-50,1 Rrc+50,50,1;%产生回波s_ut=zeros(Nr,Na);U=ones(Nr,1)*u;%扩充为矩阵T=t*ones(1,Na);for i=1:1:Ntar rn=Ptar(i,1);xn=Ptar(i,2);sigma=Ptar(i,3); rtn=rn+Rtc-Rrc; RT=sqrt(rtn2+(rtn*tan(thetaT)+xn-v*U).2); RR=sqrt(rn2+(rn*tan(thetaT)+xn-v*U).2); R=RT+RR; DT=T-R/c; phase=pi*Kr*DT.2-2*pi/lambda*R; s_ut=s_ut+sigma*exp(j*phase).*(abs(DT)Tr/2).*(abs(v*U-xn)Lsar/2);end;%距离压缩p0_t=exp(j*pi*Kr*(t-2*Rc/c).2).*(abs(t-2*Rc/c)gn);imagesc(x,r-Rc,-G),colormap(gray)grid on,axis tight,xlabel(Azimuth)ylabel(Range)title(a)原始信号)subplot(222)G=20*log10(abs(src_fut)+1e-6);gm=max(max(G);gn=gm-40;%显示动态范围40dBG=255/(gm-gn)*(G-gn).*(Ggn);imagesc(fu,r-Rc,-G),colormap(gray)grid on,axis tight,xlabel(Azimuth)ylabel(Range)title(b)距离多普勒域频谱)subplot(223)G=20*log10(abs(s2rc_fut)+1e-6);gm=max(max(G);gn=gm-40;%显示动态范围40dBG=255/(gm-gn)*(G-gn).*(Ggn);imagesc(fu,r-Rc,-G),colormap(gray)grid on,axis tight,xlabel(Azimuth)ylabel(Range)title(c)RMC后的RD域频谱)subplot(224)G=20*log10(abs(s2rcac_ut)+1e-6);gm=max(max(G);gn=gm-60;%显示动态范围40dBG=255/(gm-gn)*(G-gn).*(Ggn