normal_c.m

进行ISAR运动补偿的程序 kylsdone 方法来消除越距离单元走动,注释完整

function [s,V] = normal_c(z,rho,theta)
% function NORMAL_C.M
% Interpolation Method using cubic splines
% Usage: [s,V] = normal_c(z,rho,theta)
% Where: z = M by N matrix with samples in frequency domain
%   rho, theta = radius and angles of data points
%   s = interpolated matrix
%   V = vector that includes \fs32 \f4 rxo \fs22 \f0 dkx dky ii]\par 

close all 

% Variables
bursts = size(z,1); pul_burst = size(z,2);
thetav = theta(:,1).'; tv=thetav; dtheta = thetav(2) - theta(1);
ac = max(thetav) - min(thetav);
ca = (max(thetav) + min(thetav))/2;
rho = rho.*(4*pi/3e8);   %% frequency matrix in rad/mt 
rhov = rho(1,:); X0 = pi/(rhov(2)-rhov( 1));
rhoc = linspace(min(rhov),max(rhov)*cos(ac/2),pul_burst);
rhoy = linspace(min(rhov)*tan(min(tv)-ca),min(rhov)*tan(max(tv)-ca),bursts)
drho = rhov(2) - rhov(1); dkx = drho; dky = abs(rhoy(2) - rhoy(1));
s = zeros(size(rho)); s2 = s;

%%% Cubic interpolation in x direction
flops(0); zreal = zeros(bursts,pul_burst); zimag = zreal;
for a = 1:bursts,
projx = rhoc./cos(thetav(a) - ca);
zreal(a,:) = interp1(rho(a,:)+1.5e-5,real(z(a,:)),projx,'splines');
zimag(a,:) = interp1(rho(a,:)+1.5e-5,imag(z(a,:)),projx,'splines');
end
z = zreal + j*zimag;

%%% Cubic interpolation in y direction 
zreal = zeros(bursts,pul_burst); zimag = zreal; 
for i = 1:pul_burst,
   projy = rhoc(1,i).*tan(thetav - ca);
   zreal(:,i) = interp1(projy,real(z(:,i)),rhoy,'splines')';
   zimag(:,i) = interp1(projy,imag(z(:,i)),rhoy,'splines')';
end
s = zreal + j*zimag; fl = flops;
V=[X0 dkx dky fl];