problem4.m

music算法第四中情况,具体情况看程序中估计的源的个数与实际个数之间关系

%MUSIC Algorithm
%ELEC 6022 Sonar Coursework
%---Nan LIN
%last modified on 3 May

clear;
K=8;    %the number of signal sources
P=5;    %large directional signals present
N=20;   %the number of sensors on a line array
c=1500; %speed of light
f=1000; %frequency
theta=pi/2;     %assume that theta=90 degree.K sources are on the x-y plane
phi=10:20:150;  %assume K angles of sources
phi=phi*pi/180;
amp=5*ones(1,8);    %assume amplitudes of K sources

S(1:N,1:K)=0;

for bb=1:K;
for aa=1:N;
    S(aa,bb)=exp(j*2*pi*f*propdelay(theta,phi(bb),aa));
end;
S(1:N,bb)=amp(bb)*S(1:N,bb);
end;

Rn=0.02;         %noise power
R=S*S'+eye(N,N).*Rn;
[V D]=eig(R); % examine D matrix. pick out K largest eigenvalues

nn=1000;                 %bearing resolution
S1(1:N,1:nn)=0;
ei=V(1:N,1:N-P);            % ei correspond to N-K left eigenvalues
phix=0:180/(nn-1):180;     %assume look direction is from 0 to 180. 
phix=phix*pi/180;


for bb=1:nn;
for aa=1:N;
    S1(aa,bb)=exp(j*2*pi*f*propdelay(theta,phix(bb),aa));
end;
end;
F=1./sum(abs(ei'*S1));
phix=phix*180/pi;
plot(phix,F);
title('The MUSIC spectrum K=8 P=5');
xlabel('Phi(degree)');
ylabel('F(directional spectrum)');