isar.m

对ISAR雷达的回波信号进行转台成像

for j = 1:256
    ffts(:,j) = fftshift(fft(s(:,j)));%获得一次回波中的不同多普勒频率
end
for j = 1:255
    x1 = abs(ffts(:,j));
    x2 = abs(ffts(:,j+1));
    n1 = 1:256;
    n2 = 1:256;
    n12 = 1:256;
    numi = 0;%进行相关运算以对准
    max = sum(sigmult(abs(x1),n1,abs(x2),n2))/(sum(abs(x1).^2)*sum(abs(x2).^2))^(1/2);
    for i=-255:1:255
        [x12,n12]=sigshift(x2,n2,i);
        max1=sum(sigmult(abs(x1),n1,abs(x2),n2))/(sum(abs(x1).^2)*sum(abs(x2).^2))^(1/2);
        if ( max < max1)
            max=max1;
            numi=i;
        end
    end
    ffts0=zeros(256,1);
    if( numi > 0)
        ffts0(numi+1:256,1)=ffts(1:256-numi,j+1);
    else
        ffts0(1:256+numi,1)=ffts(1-numi:256,j+1);
    end
    ffts(:,j+1)=ffts0;
end
figure(1);
contour(abs(ffts));
title('距离对准');
% 距离对准
for j=1:255
    x1=ffts(:,j);
    x2=conj(ffts(:,j+1));
    n1=1:256;
    n2=1:256;
    n12=1:256;
    p=sum(sigmult(x1,n1,x2,n2))/abs(sum(sigmult(x1,n1,x2,n2)));
    ffts(:,j+1)=ffts(:,j+1)*p;
end
figure(2);
contour(abs(ffts));
title('相位对准');
% 相位对准
for j=1:256
    ffts(j,:)=fftshift(fft(ffts(j,:)));
end
figure(3);
contour(abs(ffts));
title('计算结果');
% 最终结果