resolution_mmusic_s.m

music高阶谱分析算法研究

                        %function    resolution_mmusic_s    
                             % function    resolution_mmusic_s_1       
% antenna_number                                天线阵元个数
% A0A                                           信号的方位角/度
% A0A_radian                                    设置信号的角度为弧度
% signal_number                                 信号源个数
% signal_frequency                              信号的中心频率
% sample_frequency                              抽样频率
% lambda_bochang                                信号源波长
% antenna_space                                 天线阵元的间距
% samplepoint_number                            对天线阵输出X的采样个数
% SNR                                           信号与噪声的对数信噪比
clc;                                      % MATLAB语言实现MUSIC算法在天线测向上的应用
clear;
close all;
antenna_number=5;                               %天线阵元个数
AOA=[-2   5];                                  %信号的方位角/度
AOA_radian=AOA*pi/180;                          %设置信号的角度为弧度
signal_number=length(AOA);                      %信号源个数
signal_frequency=6*1e9;
sample_frequency=2.5*signal_frequency;
lambda_bochang=3*1e11/signal_frequency;    
antenna_space=0.5*lambda_bochang;               %天线阵元的间距
samplepoint_number=1000;                        %采样个数
SNR=[7   7   5];                                %信号与噪声的信噪比
                        
%#####设置信号的方向矩阵azimuth_matrice
      for row_1=1:antenna_number;                 
          for column_1=1:signal_number;
              t=(row_1-1)*2*pi*antenna_space/lambda_bochang*sin(AOA_radian(column_1));
              azimuth_matrice(row_1,column_1)=exp(-j*t);
          end;
      end;
         Jm=zeros(antenna_number,antenna_number);
                 for  row_3=1:antenna_number
                      Jm(row_3,antenna_number-(row_3-1))=1;
                 end; 
               
               %生成高斯噪声
               sigma_noise=1;
               noise=normrnd(0,sigma_noise,antenna_number,samplepoint_number);
               %产生实正弦连续波信号signal
               signal_amplitude=sigma_noise*10.^(SNR/20);
               initialphase_s_1=6*pi/180;
                  for   column_s_1=1:samplepoint_number;
                        signal_1(1,column_s_1)=signal_amplitude(1)*cos(2*pi*signal_frequency*column_s_1/sample_frequency+initialphase_s_1);
                  end;
               initialphase_s_2=[96   90  84.5  78.5  72.5  66  59  51.5  43  32  6]*pi/180;   
               initial_length=length(initialphase_s_2);   
               for   initialphase_index=1:initial_length
                     signal_2=s_differ_initialphase(samplepoint_number,signal_amplitude,signal_frequency,sample_frequency,initialphase_s_2(initialphase_index)); 
                     signal_corrcoeff=corrcoef(signal_1,signal_2);
                     signal_corr(initialphase_index)=signal_corrcoeff(1,2);
                     signal_cell{initialphase_index}=[signal_1;signal_2]; 
               end;
%#####求天线阵输出信号X、及其协方差矩阵R
       measured_number=100;  
               for   initialphase_index=1:initial_length
                     for  measured_index=1:measured_number
                          X{initialphase_index,measured_index}=azimuth_matrice*signal_cell{initialphase_index}+normrnd(0,sigma_noise,antenna_number,samplepoint_number);
                          R{initialphase_index,measured_index}=1/samplepoint_number*X{initialphase_index,measured_index}*X{initialphase_index,measured_index}';
                          Rb_m{initialphase_index,measured_index}=Jm*conj(R{initialphase_index,measured_index})*Jm;
                          Rmmusic{initialphase_index,measured_index}=R{initialphase_index,measured_index}+Rb_m{initialphase_index,measured_index};
                      end;
               end;
      resoluted_propability_music=reso_propa_mmusic(R,initial_length,antenna_number,samplepoint_number,antenna_space,lambda_bochang,measured_number);
      resoluted_propability_mmusic=reso_propa_mmusic(Rmmusic,initial_length,antenna_number,samplepoint_number,antenna_space,lambda_bochang,measured_number);
      figure(1)
      plot(signal_corr,resoluted_propability_music,signal_corr,resoluted_propability_mmusic,'r:');
      xlabel('信号源相关系数\rho');   ylabel('信号源AOA分辨概率');
      grid;       legend('music','mmusic');    axis([0,1,0,1]); 
      figure(2)
      subplot(2,1,1);   plot(signal_corr,resoluted_propability_music);  grid;   legend('music'); title('信号源AOA分辨概率');
      subplot(2,1,2);   plot(signal_corr,resoluted_propability_mmusic);   grid;   legend('mmusic');
      xlabel('信号源相关系数\rho');