1、仿真图如下:N=li A 4 III l V F|i 4 fi | 4l11 F 1 K| I 41 1 III 1I 1 II f1 1 ll1 V 1丄 L It L i T 7M 1 1 4id i i 41 1 1 4L*lLit丄i | iI t I j t 4* * i1 JL 9 I i| Ji i il i i2 46 *1 *0 6 0 0 5 1 1 5thetaradian*2. 波束宽度与波达方向及阵元数的关系clcclear allclose allima=sqrt(-1);element_num1=16; %阵元数element_num2=128;element_n
2、um3=1024;lamda=0.03; %波长为 0.03 米d=1/2*lamda; %阵元间距与波长的关系 theta=0:0.5:90;length(theta); fai(j)=theta(j)*pi/180-asin(sin(theta(j)*pi/180)-lamda/(element_num1*d); psi(j)=theta(j)*pi/180-asin(sin(theta(j)*pi/180)-lamda/(element_num2*d); beta(j)=theta(j)*pi/180-asin(sin(theta(j)*pi/180)-lamda/(element_nu
3、m3*d); plot(theta,fai,r,theta,psi,b,theta,beta,g),grid on xlabel(thetaWidth in radians 波束宽度与波达方向及阵元数的关系 ) 仿真图如下:波束宽度与波达方向及阵元数的关系0.70 6匸Jo.3-0503 et h47060903.当阵元间距d /2时,会出现栅瓣,导致空间模糊。8P apj三CEelamda为2液长-10 12lamda为09咅波长4.类似于时域滤波,天线方向图是最优权的傅立叶变换仿真程序和仿真图如下:clc clear alleleme nt_num=32; % 阵元数source_ num
4、=1; % 信源数d_lamda=1/2; %阵元间距与波长的关系theta=li nspace(-pi/2,pi/2,200);thetaO=O; %来波方向w=exp(ima*2*pi*d_lamda*s in (theta0)*0: for j=1:le ngth(theta);a=exp(ima*2*pi*d_lamda*s in (theta(j)*0:subplot(1,2,1)plot(theta,abs(p),grid on xlabel(theta/radia n) ylabel() title(按定义的方向图) pfft=fftshift(fft(w,128);subplo
5、t(1,2,2)plot(li nspace(-pi/2,pi/2,128),abs(pfft),grid on xlabel(FFT_amplitude最优权的傅里叶变换抿定史的方向图35最优权的傅里叶变摄ai.J.ji ii1 II1 :3*q|1ciZ 1J15-1= I1 iIIii!lHi iiLIcw |1 -i2 -1 1 25. %最大信噪比准则方向图和功率谱 clear all; close all; ima=sqrt(-1);theta=-90:%阵元数为 8%间距为半波长 %范围 %来波方向theta1=20;%干扰方向L=512; %采样单元数for i=1:Lamp0
6、=10*randn(1);amp1=200*randn(1);ampn=1;s(:,i)=amp0*exp(ima*2*pi*1/2*sin(theta0*pi/180)*0:element_num-1j(:,i)=amp1*exp(ima*2*pi*1/2*sin(theta1*pi/180)*0: n(:,i)=ampn*(randn(element_num,1)+ima*randn(element_num,1);Rs=1/L*s*s;%信号自相关矩阵Rnj=1/L*(j*j+n*n%干扰+噪声的自相关矩阵V,D=eig(Rs,Rnj);% (Rs,Rnj)的广义特征值和特征向量D,I=s
7、ort(diag(D);%排序Wopt=V(:,I(8);%最优权矢量length(theta) a=exp(ima*2*pi*d_lamda*sin(theta(j)*pi/180)*0: f(j)=Woptp(j)=a*Rs*a+a*Rnj*a;end F=20*log10(abs(f)/max(max(abs(f); P=20*log10(abs(p)/max(max(abs(p);subplot(121) plot(theta,F);grid on;hold on plot(theta0,-50:0,.plot(theta1,-50:) xlabel(theta/0F in dBmax
8、-SNR 方向图 axis(-90 90 -50 0);hold onsubplot(122) plot(theta,P,grid ontheta/O功率 in dBmax-SNR 功率谱 仿真图如下:-10-20-30轻-4QB -so*70-80-90-100 -50 fl SO 100the?l 屮口6.%ASC旁瓣相消-MSE准则M=32;%辅助天线的数目d_lamda=.5;theta0=-30;theta仁60;%米样单兀数s=zeros(1,512);%预划分一个区域for ii=1:L;ampO=1*ra ndn (1); %信号的幅度随机产生,保证信号之间是不相关的amp1=
9、200*ra ndn (1);amp n=1;jam(:,ii)=amp1*exp(ima*2*pi*0.5*si n(theta1*pi/180)*0:M-1)+amp n*(ra ndn (M,1)+ima*ra ndn (M,1); % 干扰 + 噪声s(ii)=amp0*exp(ima*2*pi*0.5*si n(theta0*pi/180)+amp1*exp(ima*2*pi*0.5*si n(thet a1*pi/180)+amp n*(ra ndn (1,1)+ima*ra ndn (1,1);% 接收信号(信号 + 干扰 + 噪声)s0(ii)=amp0*exp(ima*2*p
10、i*0.5*si n(theta0*pi/180);%噪声自相关矩阵,相当于X (t)Rx=1/L*jam*jamr_xd=1/L*jam*sWopt=p in v(Rx)*r_xd;delta=s0-(s-Wopt*jam);delta仁abs(mea n(delta42)-(mea n( delta).A2) % 方差for jj=1:le ngth(theta) a=exp(ima*2*pi*5*s in (theta(jj)*0: f(jj)=WoptF=20*log10(abs(f)/(max(max(abs (f);figure(1)plot(theta*180/pi,F),gri
11、d on,hold onplot(theta0,-50:theta/oF/dBMSE准则下的方向图%可为x轴和y轴设置一个极限范围胎E准则下的方向图theta/c7. %线性约束最小方差 (LCMV) 准则 clc;clear all ;%阵元数90-0.3; %搜索范围 %三个信号源的来波方向theta1=30;theta2=60;amp1=100*randn(1);amp2=10*randn(1);ampn=10;x(:)+.amp1*exp(ima*2*pi*1/2*sin(theta1*pi/180)*0:amp2*exp(ima*2*pi*1/2*sin(theta2*pi/180)
12、*0:)+. ampn*(randn(element_num,1)+ima*randn(element_num,1); endRx=1/L*x* xsteer1=exp(ima*2*pi*1/2*sin(theta0*pi/180)*0:steer2=exp(ima*2*pi*1/2*sin(theta1*pi/180)*0:steer3=exp(ima*2*pi*1/2*sin(theta2*pi/180)*0:C=steer1 steer2 steer3;F=1 0 1 %把三个方向都作为来波方向w=inv(Rx)*C*(inv(C*inv(Rx)*C)*F; a=exp(ima*2*pi
13、*d_lamda*sin(theta(j)*pi/180)*0: f(j)=wp(j)=1/(a*inv(Rx)*a);f=10*log10(abs(f)/(max(max(abs(f);subplot(121)plot(theta,f),grid on,hold onplot(theta0,-20:plot(theta1,-20:plot(theta2,-20:Capon beamforming 方向图 axis(-90 90 -20 0);P=10*log10(abs(p)/(max(max(abs(p); subplot(122)plot(theta,P),grid on,hold on
14、 plot(theta0,-20:) plot(theta1,-20:) plot(theta2,-20:功率 /dBC apon beamformi ng 功率谱theta/o6-8121416-ie-SC叩on beamfiornning功率谱9询百-100 -60 0theta/g8. %Capon beamforming Clc;%阵元间距与波长的关系theta=-9O:O.5:9O;%范围theta1=2O;theta2=6O;L=1000; % 采样单元数ampO=1O*ra ndn;信号的幅度随机产生,保证信号之间是不相关的amp2=2OO*randn(1);ampn=3;,i)
15、=ampO*exp(ima*2*pi*1/2*sin(thetaO*pi/18O)*O:amp1*exp(ima*2*pi*1/2*sin(theta1*pi/18O)*O:amp2*exp(ima*2*pi*1/2*sin(theta2*pi/18O)*O:R=inv(Rx);steer=exp(ima*2*pi*1/2*sin(thetaO*pi/18O)*O:w=R*steer/(steer*R*steer);%Capon 最优权矢量*R*a);F=20*log10(abs(f)/(max(max(abs(f);P=20*log10(abs(p)/(max(max(abs(p);%此处是
16、功率的对数形式Figure;plot(theta,F),grid on,hold onplot(theta2,-50:subplot(122)plot(theta,P),grid onCapon beamforming 功率谱 Capoil b-eamforming方向冒50 0 5Cth&ta/oCapon b朋nifoiming功率4普9. %不同方法估计协方差矩阵的Cap on波束形成 clc; %阵元数为 8theta1=50; %干扰方向%采样单元数amp1=50*randn(1);ampn=0.5;,i)=ampn*exp(ima*2*pi*randn(1)*0:Rx=1/L*(s
17、+j+n)*(s+j+n)% 接收信号自相关矩阵Rnj=1/L*(j+n)*(j+n)% 干拢+噪声的自相关矩阵e=exp(ima*2*pi*d_lamda*sin(theta0*pi/180)*0:% 来波方向信号Wopt_Rx=inv(Rx)*e/(e*inv(Rx)*e);% 采用接收信号的权矢量Wopt_Rnj=inv(Rnj)*e/(e*inv(Rnj)*e);% 采用干拢 +噪声信号的权矢量length(theta)a=exp(ima*2*pi*d_lamda*sin(theta(j)*pi/180)*0: f1(j)=Wopt_Rxf2(j)=Wopt_RnjF1=20*log1
18、0(abs(f1)/max(max(abs(f1);F2=20*log10(abs(f2)/max(max(abs(f2);plot(theta,F1,theta,F2,),grid on;F(1,2)/dB不同方法估计协方差矩阵的Cap on波束形成theia J10. %多点约束的Capon波束形成和方向图eleme nt_num=8;d_l amda=1/2;0.3:%搜索范围theta2=50;Rx=zeros(eleme nt_nu m,eleme nt_nu m);%P 生协方差矩阵 for i=1:amp0=10*ra ndn (1);amp1=10*ra ndn (1);amp2=50*ra ndn (1);namp=0.5*randn(1);%噪声的幅度随机产生,保证噪声与信号之间是不相关的J(:)+. amp2*exp(ima*2*pi*1/2*sin(theta2*pi/180)*0:namp*exp(ima*2*pi*randn(1)*0: x(:,i);%表示接收信号Rx=Rx+1/L*x*xw=amp0*exp(ima*2*pi*1/2*sin(theta0*pi/180)*0:)+. amp2*exp(ima*2*pi*1/2*sin(theta2*pi
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