rda_rmc.m

条带式合成孔径雷达的cs。RDA。RMA算法 作者何志华

%%Range Migration Correction,RMC
%NUDT,Hezhihua
%E-mail:[e-mail]
%last update:24/6/2005

load sarecho.mat x y kx ky Xc dx;
load sarecho.mat kxc Nx Ny ;
load sarecho.mat sxc_xky p0_ky;

RM_xky=(x'*ones(1,Ny)).*(kxc./sqrt(kxc^2-(ones(Nx,1)*ky).^2)-1);%距离迁移量


method=1;%%选取不同的插值方法

if method==1
%%最邻域近似插值
RMC=zeros(Nx,Ny);
RM=round(RM_xky/dx);
for i=1:Nx-max(max(RM))
    for j=1:Ny
        RMC(i,j)=sxc_xky((i+RM(i,j)),j);
    end
end

elseif method==2
%%截断sinc插值
P=8/2;%8点sinc插值
RMC=zeros(Nx,Ny);
RM=floor(RM_xky/dx);
for i=P:Nx-max(max(RM))-P
     for j=1:Ny
       T=RM(i,j)+(-P+1:P);
       f=sxc_xky(i+T,j).';
       RMC(i,j)=sum(f.*sinc(RM_xky(i,j)/dx-T));
     end
     i
end

else
%%线性插值
RMC=zeros(Nx,Ny);
RM=floor(RM_xky/dx);
for i=2:Nx-max(max(RM))-1
    for j=1:Ny
        f1=sxc_xky(i+RM(i,j),j);
        f2=sxc_xky(i+RM(i,j)+1,j);
        RMC(i,j)=f1+(f2-f1)*(RM_xky(i,j)-RM(i,j)*dx)/dx;
    end
end

end

sxcrmc_xky=RMC;
%%方位压缩
sxcrmcyc_xky=sxcrmc_xky.*(ones(Nx,1)*conj(p0_ky));
sxcrmcyc_xy=fftshift(ifft(fftshift(sxcrmcyc_xky).')).';
save rda_img.mat sxcrmcyc_xy x y Xc Nx Ny%存储变量

%%结果显示
subplot(221)
plot_img(ky,x-Xc,sxc_xky,30),grid on
axis([-1,1,-20,70])
xlabel('ky domain(cross-range),m^-^1')
ylabel('x domain(range),m')
title('|s_x_c(x,k_y)|')

subplot(222)
load sarecho.mat sxcyc_xy;
plot_img(y,x-Xc,sxcyc_xy,40),grid on
axis([-100,100,-20,70])
xlabel('y domain(cross-range),m')
ylabel('x domain(range),m')
title('|s_x_c_y_c(x,y)|')

subplot(223)
plot_img(ky,x-Xc,sxcrmc_xky,30),grid on
axis([-1,1,-20,70])
xlabel('ky domain(cross-range),m^-^1')
ylabel('x domain(range),m')
title('|s_x_c_r_m_c(x,k_y)|')

subplot(224)
plot_img(y,x-Xc,sxcrmcyc_xy,40),grid on
axis([-100,100,-20,70])
xlabel('y domain(cross-range),m')
ylabel('x domain(range),m')
title('|s_x_c_r_m_c_y_c(x,k_y)|')