matlab_单脉冲和差波束测角程序_实现了线阵8阵元的和差波束测角，利用全阵同时形成两个波束和差波束

%此程序实现了线阵8阵元的和差波束测角，利用全阵同时形成两个波束，形成和差波束 %随着测量角度的增大其误差也逐渐增大，这是由于这种方法的近似所致和波束扫描时变胖 %%%%%%%%%%%%%%%%%%%%% %%扫描信号方向与起始角度差别，从而画出误差曲线 %%%%%%%%%%%%%%%%%%%%% close all; clear all; clc; ele=8; %阵元数 d_lama=0.5; theta1=10; %起始角度 detal=0.1;%偏角扫描增量 i=0; x=5:detal:15; err0=zeros(1,length(x)); err1=zeros(1,length(x)); rate_i=zeros(1,length(x)); diff=3;%两个波束相对等信号轴的偏角 for thetal_singal=5:detal:15; % 信号方向 i=i+1; theta2=[theta1-diff theta1+diff]*pi/180; %%%%%%%%%%误差的大小与信号方向和diff有关系：thetal_singal=1;diff=7; % thetal_singal=2;diff=7; % thetal_singal=0.5;diff=7; %%%%%%%%%%信号方向与起始角度差别越小越精确 %%%%%%%%%%当起始信号大时候，diff越小越精确 %%%%%%%%%%%导向矢量 a1=exp(j*pi*(0:ele-1).'*sin(theta2(1))); a2=exp(j*pi*(0:ele-1).'*sin(theta2(2))); a_singal=exp(j*pi*(0:ele-1).'*sin(thetal_singal*pi/180)); alfa=linspace(-pi/2,pi/2,1000); a=exp(j*pi*(0:ele-1).'*sin(alfa)); % wn1=chebwin(ele,40);%切辟雪夫权00000 % wn2=0.54-0.46*cos(2*pi*(0:ele-1)/(ele-1));%海明权 % a1=diag(wn1)*a1; % a2=diag(wn1)*a2; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%利用公式计算角度 a_singal=exp(j*pi*(0:ele-1).'*sin(thetal_singal*pi/180)); p1_singal=a1'*a_singal; p2_singal=a2'*a_singal; g_sum_singal=abs(p1_singal)+abs(p2_singal); g_diff_singal=abs(p1_singal)-abs(p2_singal); % sum_gain=g_sum(thetal_singal*pi/180/pi/2*500); % diff_gain=g_diff(thetal_singal*pi/180/pi/2*500); rate=(g_diff_singal/g_sum_singal); % 8.4*2 % alfa1_semi=0.886*2/7*csc(theta1*pi/180); % alfa1_semi=acos(cos(theta1*pi/180)-0.443*2/7)-acos(cos(theta1*pi/180)+0.443*2/7); F_thetal=sin(ele*pi*d_lama*(sin(theta1*pi/180)-sin(theta2(1))))/((sin(pi*d_lama*(sin(theta1*pi/180)-sin(theta2(1)))))); % F_diff=diff('sin(ele*2*pi*d_lama*sin(thetal*pi/180))/(ele*2*(sin(pi*d_lama*sin(thetal*pi/180))))'); % x=thetal; a_thetal=exp(j*pi*(0:ele-1).'*sin(theta1*pi/180)); if rate>0 F_thetal_thetal=abs(a2'*a_thetal); F_diff_theta=(cos(ele*pi*1/2*(sin(theta1*pi/180)-sin(theta2(2))))*ele*pi*1/2*cos(theta1*pi/180)... *sin(pi*1/2*(sin(theta1*pi/180)-sin(theta2(2))))... -sin(ele*pi*1/2*(sin(theta1*pi/180)-sin(theta2(2))))... *cos(pi*1/2*(sin(theta1*pi/180)-sin(theta2(2))))... *pi*1/2*cos(theta1*pi/180))/(sin(pi*0.5*(sin(theta1*pi/180)-sin(theta2(2))))^2); end if rate<0 F_thetal_thetal=abs(a1'*a_thetal); F_diff_theta=(cos(ele*pi*1/2*(sin(theta1*pi/180)-sin(theta2(1))))*ele*pi*1/2*cos(theta1*pi/180)... *sin(pi*1/2*(sin(theta1*pi/180)-sin(theta2(1))))... -sin(ele*pi*1/2*(sin(theta1*pi/180)-sin(theta2(1))))... *cos(pi*1/2*(sin(theta1*pi/180)-sin(theta2(1))))... *pi*1/2*cos(theta1*pi/180))/(sin(pi*0.5*(sin(theta1*pi/180)-sin(theta2(1))))^2); end rate_i(i)=rate; % F_thetal_thetal=(F_thetal+F_theta2)/2; % F_diff_theta=(abs(F_diff_thetal)+abs(F_diff_theta2))/2; theta_cal=rate*F_thetal_thetal/abs(F_diff_theta); theta_cal=abs(theta_cal*180/pi); format short % if rate>=0 % disp('信号方向为法向偏左') % disp('真实的信号方向:(度)') % thetal_singal % disp('计算的信号方向:(度)') % theta1-theta_cal % disp('计算的绝对误差:(度)') err0(i)=abs(theta1-theta_cal)-abs(thetal_singal); % disp('计算的相对误差:') err1(i)=(abs(theta1-theta_cal)-abs(thetal_singal))/abs(thetal_singal); % end % if rate<0 % disp('信号方向为法向偏右') % disp('真实的信号方向:(度)') % thetal_singal % disp('计算的信号方向:(度)') % theta1+theta_cal % disp('计算的绝对误差:(度)') % abs(theta1+theta_cal)-abs(thetal_singal) % disp('计算的相对误差:') % (abs(theta1+theta_cal)-abs(thetal_singal))/abs(thetal_singal) %end end % figure(1) % p1=a1'*a; % p2=a2'*a; % plot(alfa*180/pi,((abs(p1)))) % hold on; % plot(alfa*180/pi,(abs(p2)),'r') % grid on;zoom on; % xlabel('角度') % ylabel('增益') % title('两个部分重叠的方向图') % % % figure(2) % g_sum=abs(p1)+abs(p2); % g_diff=abs(p1)-abs(p2); % plot(alfa*180/pi,((g_sum))) % hold on; % plot(alfa*180/pi,((g_diff)),'r--') % xlabel('doa-degree'),ylabel('gain'); % title('和差波束') % legend('和波束方向图','差波束方向图') % grid on;zoom on; figure(10) plot(x,err0,'b*');grid on;zoom on;title('绝对误差曲线'); xlabel('角度') ylabel('角误差') figure(11) plot(x,err1,'b*');grid on; zoom on;title('相对误差曲线'); xlabel('角度') ylabel('角误差')