zaoshengzikongjian.m

噪声子空间法 进行波达估计 算法较复杂 不过效果明显

clear all; 
close all; 
clc 
N_x=1024;
N=8;
A=[4 3 3]; 
l=1.8;
d=0.5*l;
M=3;
w=[pi/6 pi/10 pi/8]';
xx=pi/6;yy=0*pi/4;zz=pi/6+4*pi/180;
B=[1 exp(-j*2*pi*d*sin(xx)/l) exp(-j*2*2*pi*d*sin(xx)/l) exp(-j*2*3*pi*d*sin(xx)/l) exp(-j*2*4*pi*d*sin(xx)/l) exp(-j*2*5*pi*d*sin(xx)/l) exp(-j*2*6*pi*d*sin(xx)/l) exp(-j*2*7*pi*d*sin(xx)/l); 
1 exp(-j*2*pi*d*sin(yy)/l) exp(-j*2*2*pi*d*sin(yy)/l) exp(-j*2*3*pi*d*sin(yy)/l) exp(-j*2*4*pi*d*sin(yy)/l) exp(-j*2*5*pi*d*sin(yy)/l) exp(-j*2*6*pi*d*sin(yy)/l) exp(-j*2*7*pi*d*sin(yy)/l); 
1 exp(-j*2*pi*d*sin(zz)/l) exp(-j*2*2*pi*d*sin(zz)/l) exp(-j*2*3*pi*d*sin(zz)/l) exp(-j*2*4*pi*d*sin(zz)/l) exp(-j*2*5*pi*d*sin(zz)/l) exp(-j*2*6*pi*d*sin(zz)/l) exp(-j*2*7*pi*d*sin(zz)/l)]'; 
xxx=2*exp(j*w*[0:N_x-1]);
t=[0:N_x-1]; 
xxx=2*sin(w*t);
subplot(211); 
plot(t(1:128),xxx(1:128)) 
x=B*xxx+randn(8,N_x)+j*randn(8,N_x);
R=x*x'; 
[V D]=eig(R); 
[lambda,index] = sort((diag(D))); 
UU=V(:,index(1:5)); 
theta=-90:0.1:90;
for i = 1:length(theta) 
AA=[1 exp(-j*2*pi*d*sin(theta(i)/180*pi)/l) exp(-j*2*2*pi*d*sin(theta(i)/180*pi)/l) exp(-j*2*3*pi*d*sin(theta(i)/180*pi)/l) exp(-j*2*4*pi*d*sin(theta(i)/180*pi)/l) exp(-j*2*5*pi*d*sin(theta(i)/180*pi)/l) ,exp(-j*2*6*pi*d*sin(theta(i)/180*pi)/l) exp(-j*2*7*pi*d*sin(theta(i)/180*pi)/l)];
WW=AA*UU*UU'*AA'; 
Pmusic(i)=abs(1/WW);
PCap(i) = abs(1/(AA*inv(R)*AA')); 
end 
Pmusic = 20*log10(Pmusic); 
sita=-90:0.1:90; 
subplot(212); 
semilogy(sita,Pmusic); 
grid 
xlabel('rad')