lfmplottd2.m

Programs developed during Radar Course

clc
M=128;

T=0.001;
tb=T/(M-1);
t=[0:tb:T];
df=10^4/T;
% m=[1:M];
% phi=pi/M*(m-1).^2-pi*(m-1);
uT=exp(j*pi*df*(t).^2);
uTr=real(uT);
v1=randn(size(uTr));
uTn=uTr+v1; %-------Add noise
st=xcorr(uTn,uTr);
N=size(st);

subplot(3,1,1);plot(uTr);title('Real part of LFM')
subplot(3,1,2);plot(uTn);title('Noisy Received Signal')
subplot(3,1,3);plot(st);title('Single target(detcted)')
% ----------------------------Two targets----------------------------------
TT=2*[uTr zeros(1,15)]+[zeros(1,15) uTr];
v2=randn(size(TT));
% figure;plot(tt);title('Two Targets')
ttn=TT+v2;
tt=xcorr(ttn,uTr);

figure;
subplot(3,1,1);plot(TT);title('Two Targets')
subplot(3,1,2);plot(ttn);title('Noisy Received Signal')
subplot(3,1,3);plot(tt);title('targets detected')
% ---------------------------Initial W0------------------------------------
a=length(uTr);
b=length(tt);
putr1=[zeros(1,78) uTr];
putr2=[putr1 zeros(1,79)];
% % w0=inv(putr2*putr2')*putr2;
ftt=real(fftshift(fft(tt)));
futr=real(fftshift(fft(putr2)));
w0=inv(futr'*futr)*futr';
y1=w0*ftt;
% y2=ifft(ifftshift(y1));
figure;plot(y1,'k');title('Initialization stage')


% %------------------------------------------------------------------------
ro2=abs(y1'*y1);
% r2=padarray(ro2,[7 7]);
R=xcorr(v1);
lr=length(R);
% r=((lr+1)/2);
nr=toeplitz(R((lr+1)/2:end));
Rp=padarray(nr,[79 79]);
Rp(:,286)=[];
Rp(286,:)=[];
C=ro2*futr'*futr;
I=eye(285,285);
w1=ro2*(inv((C-(0.01*I))+Rp))*futr';
y2=w1'*y1;
figure;plot(y2,'k');title('First Stage')

% %------------------------------------------------------------------------
ro3=abs(y2'*y2);
R=xcorr(v1);
lr=length(R);
% r=((lr+1)/2);
nr=toeplitz(R((lr+1)/2:end));

% Rp=padarray(R,[71 71]);
C=ro3*futr'*futr;
I2=eye(285,285);
w2=ro3*(inv((C-(0.01*I2))+Rp))*futr';
y3=w2'*y1;
figure;plot(y3,'k');title('Initialization stage3')