mocomp.rar_In Motion_SAR_motion SAR_motion compensation

PRF=300; Timg=3; vr=200; fc=4.5e9; La=2; theta=45; rotation=0; R0=20e3; Xc=R0*cos(theta*pi/180); Zc=R0*sin(theta*pi/180); X0=200; Tp=0.25e-5; B0=100e6; cj=sqrt(-1); c=3e8; ic=1/c; lambda=c/fc; eta=linspace(0,Timg,PRF*Timg); Kr=B0/Tp; dt=1/(2*B0); Ts=(2*(sqrt(Xc^2+Zc^2)-X0))/c; Tf=(2*(sqrt(Xc^2+Zc^2)+X0))/c; Ka=(2*vr^2)./(lambda*(sqrt(Xc^2+Zc^2))); rbins=2*ceil((.5*(Tf-Ts))/dt); t=Ts+(0:rbins-1)*dt; s=zeros(PRF*Timg,rbins); xn=[100]; yn=[0];zn=[0]; Fn=[1];ze=zeros(PRF*Timg,1);for j=1:(PRF*Timg);ze(j)=sin(j*pi*(1/180));end for j=1:(PRF*Timg); for i=1:length(xn); wa=sinc(La*(atan(vr*(eta(j)-Timg/2+yn(i)/vr)/sqrt(Xc^2+Zc^2)))/lambda).^2; R=sqrt((Xc+xn(i))^2+(Zc+ze(j)-zn(i))^2+vr^2*((eta(j)-Timg/2+(yn(i))/vr)^2)); td=t-2*R/c; s(j,:)=s(j,:)+0.5*wa*exp(-cj*(4*pi*fc*(1/c)*R)+cj*pi*Kr*(td.^2-td*Tp)).*(td >= 0 & td <= Tp); end end; s0=zeros(PRF*Timg,rbins); fs0=zeros(PRF*Timg,rbins); parfor j=1:(PRF*Timg) rce(j)=(ze(j)^2)/(2*sqrt(Xc^2+Zc^2))-(ze(j)); td0=t-2*(sqrt(Xc^2+Zc^2)/c)-2*rce(j)/c; s0(j,:)=exp(-cj*2*pi*(rce(j))/lambda)*exp(cj*pi*Kr*((td0.^2)-td0*Tp)).*(td0 >= 0 & td0 <= Tp); fs0(j,:)=fty(s0(j,:)); end parfor k=1:(PRF*Timg); a(k,:)=fty(s(k,:)); % Range FFT end; for l=1:rbins;b(:,l)=a(:,l).*conj((fs0(1,l)));end parfor k=1:(PRF*Timg); d(k,:)=ifty(b(k,:)); % Range IFFT end for l=1:rbins; fsmb(:,l)=ftx(d(:,l)); end; deltaR=(2*lambda^2*sqrt(Xc^2+Zc^2).*(Ka*(Timg*0.5-eta)).^2)/(8*vr^2); cells=round(deltaR/56); fsmb2=fsmb; for k=1:Timg*PRF; for m=1:rbins-max(cells) fsmb2(k,m)=fsmb(k,m+cells(k)); end end parfor l=1:rbins; h1(:,l)=iftx(fsmb2(:,l)); % Azimuth IFFT end parfor l=1:rbins; rel(:,l)=(ze.^2)./(c*t(l))-(ze); end parfor l=1:rbins; rdiff(:,l)=rel(:,l)-rce'; end parfor l=1:rbins; h(:,l)=ftx(h1(:,l).*exp(cj*2*pi*rdiff(:,l)/lambda)); % Azimuth IFFT end smb0=exp(cj*pi*Ka.*eta.*(2*eta(PRF*Timg/2+1)-eta)); fsmb0=ftx(smb0); for l=1:rbins; fsac(:,l)=h(:,l).*conj(transpose(fsmb0)); sac(:,l)=iftx(fsac(:,l)); end imagesc(c*t*.5,vr*(eta-Timg/2),abs(sac))