【DOA估计】 music算法宽带信号（线性调频信号）DOA估计【含Matlab源码 2677期】.zip

%%%%%%%%%%%%%%%基于线性调频信号的MUSIC算法 clear; close all; j=sqrt(-1); c=3e8; tao=10e-6;%采样间隔 fs=100e6;%采样频率 M=8; f1_l=29.9e6; f1_h=30.1e6;%信号的低频和高频 f2_l=30.1e6; f2_h=29.9e6;%此种情况下，中频相同且不相关，且为窄带信号 f1_c=(f1_l+f1_h)/2;%中频，且相同 w0=2*pi*f1_c; B1=f1_h-f1_l;%带宽 kc1=B1/tao;%调制斜率 kc2=-B1/tao; N_fs=fix(tao*fs);% 采样点数 t0=(0:N_fs-1)/fs; snr=10; theta=[-10 20];%入射角度 N_source=length(theta); lambda=c/f1_c;%波长及阵元间距 d=lambda/2; dd=(0:M-1)*d; mecnt=100; F = fs/N_fs; f_xlabe = ((0:N_fs-1)-N_fs/2)*F; %%%%%%%%%%%流行矩阵 delay=zeros(M,N_source); for i=1:N_source delay(:,i)=dd.'*sin(theta(i)*pi/180)/c; end % A=zeros(M,N_source); % for i2=1:N_source % A(:,i2)=exp(j*2*pi*dd.'*sin(theta(i)*pi/180)/c); % delay(:,i2)=dd.'*sin(theta(i2)*pi/180)/c % end %%%%%%%%%%%产生线性调频信号 X1=zeros(M,N_fs); X2=zeros(M,N_fs); for h1=1:M; t1=t0-delay(h1,1); X1(h1,:)=exp(j*2*pi*(f1_l*t1+1/2*kc1*t1.^2)); end for h2=1:M; t2=t0-delay(h2,2); X2(h2,:)=exp(j*2*pi*(f2_l*t2+1/2*kc2*t2.^2)); end X=X1+X2; X_out=awgn(X,snr,'measured'); mesh(1:1000,1:8,abs(X_out)); %%%%%%%music算法———————————————————— R=(X_out*(X_out)')/N_fs; [edv,d]=eig(R); d=diag(d);%取出对角矩阵 [d_sort pre]=sort(abs(d),'ascend');%对特征值d进行从小到大排列并取出其索引 edv_sort = edv(:,pre); %对应特征值从小到大的特征向量 Un = edv_sort(:,1:M-N_source); %取出噪声的特征向量 %对角度进行搜索 ang = (-90:1:90); p = zeros(1,length(ang)); for loop = 1:length(ang) %-90~90度搜索 a = exp(-j*w0*dd.'*sin(ang(loop)*pi/180)/c); tem = a'*Un; p(1,loop) = 1/(tem*tem'); end p_max = max(p); p=10*log10(p/p_max); figure; plot(ang,p); xlabel('angle(degree)'); axis([-90 90 -60 5]); ylabel('magnitude(db)'); title('MUSIC算法') grid on;