CFAR修改

EchoProcess/CFARV2.m

@@ -0,0 +1,158 @@
+%% Target Detection Pd Pfa,CA-CFAR
+close all;clear all;clc;
+N = 1e4;        %Points
+n = 1:N;
+SNR = 10;       %SNR in dB
+Pfa = 1e-3;     
+sigma_dB = 0;   %Noise power in dB
+sigma = db2pow(sigma_dB);           %Noise Power=1w
+
+noise = sigma/sqrt(2)*(randn(1,N)+1i*randn(1,N));
+A = sqrt(sigma^2 * 10^(SNR/10));    %Target signal
+T_fix =  sqrt(-sigma^2*log(Pfa));   %fix thresholding ֻ�����������й� ������������Ϊ����
+c = 500;                            %one side,ref cell = c-guardc
+guardc = 10;   
+CUTIdx = N/2;   %Ŀ��ĸ���
+%Simulation of target detection%
+sample = rand(1,N) < 0.001;  %��������ɼ���Ŀ�� ��Ӧλ�÷���1
+A0 = A .* sample;            
+%A1 = abs(A0 + noise.*sample);
+signal1 = A0 + noise;              %Receive signal
+
+figure(1);
+idx_target = find(A0 > 0);  %��ʵĿ��λ�� 
+idx_detect = find(abs(signal1) > T_fix); %ͨ����ֵ��⵽��Ŀ��
+plot(n,abs(signal1),'-o','MarkerIndices',idx_detect,'MarkerSize',10);
+hold on; plot(n(idx_target),abs(signal1(1,idx_target)),'p','MarkerEdgeColor','r','MarkerFaceColor','r');
+hold on; plot(n,T_fix*ones(1,N));
+xlim([c+2,N-c-1]);
+
+%Evaluation of Pd & Pfa %
+signal2 = A + noise;
+disp('Detection Rate��')
+Pd_est  = sum(abs(signal2) > T_fix) / N
+disp('False alarm Rate��')
+Pfa_est = sum(abs(noise(1,c+2:N-c-1)) > T_fix) / N
+
+%Simulation of CFAR detection
+%Ncells = 23;%Ntrails =1e4;
+
+
+%signal = noise;
+sample = rand(1,N) < 0.001;  %��������ɼ���Ŀ��
+signal = A.*sample;
+signal = signal+noise;
+%signal(1,CUTIdx) = signal(1,CUTIdx) + A;  % 5000��Ŀ��
+k = Pfa^(-1/(2*(c-guardc)))-1;   %����ϵ����ʽ���ھ�ֵΪ0�µĶ�����˹���������£�  
+
+T_cfar = T_fix .* ones(1,N);
+for j=c+1:N-c
+    pn = sum(abs(signal(1,(j-c:j-guardc-1))).^2) + sum(abs(signal(1,(j+guardc+1:j+c))).^2);
+    T_cfar(j) =k.*abs(pn);
+end
+figure(2);
+idx2_target = find(sample > 0);  %��ʵĿ��λ��
+idxC = find(abs(signal).^2 > T_cfar);         %���ڼ����ֵ��Ŀ��
+plot(n,abs(signal).^2,'-o','MarkerIndices',idxC,'MarkerSize',10);
+hold on; plot(n(idx2_target),abs(signal(1,idx2_target)).^2,'p','MarkerEdgeColor','r','MarkerFaceColor','r');
+%hold on;stem(N/2,abs(signal(1,N/2)).^2,'-p','MarkerEdgeColor','r','MarkerFaceColor','r');
+hold on;plot(n,T_cfar);
+xlim([c+2,N-c-1]);
+Pfa_cfar = sum(abs(noise(1,c+2:N-c-1)).^2 > T_cfar(1,c+2:N-c-1))./(N-2*c)
+% %Pfa_np = sum(x(CUTIdx,:)>T_ideal)/Ntrials
+
+%% Pd
+N_trial = 10000;     
+sum_fix = 0;
+sum_cfar = 0;
+T_fix =  sqrt(-sigma^2*log(Pfa)); 
+for n = 1:N_trial
+    noise = sigma/sqrt(2)*(randn(1,N)+1i*randn(1,N));
+    signal = noise;
+    signal(1,CUTIdx) = signal(1,CUTIdx) + A;          %5000��Ŀ��
+    sum_fix = sum_fix + (abs(signal(1,CUTIdx)) > T_fix);
+
+    pn = sum(abs(signal(1,(CUTIdx-c:CUTIdx-guardc-1))).^2) + sum(abs(signal(1,(CUTIdx+guardc+1:CUTIdx+c))).^2);
+    T_cfar0 =k.*abs(pn);
+    sum_cfar = sum_cfar + (abs(signal(1,CUTIdx)).^2 > T_cfar0);
+end
+pd_fix = sum_fix / N_trial   %��ֵ�̶��µĺ��龯��
+pd_cfar = sum_cfar / N_trial
+
+%% CFAR COMPARE
+close all;clear all;clc;
+N = 6e3;        
+n = 1:N;
+SNR = 20;       
+Pfa = 1e-6;     
+sigma_dB = 0;   
+sigma = db2pow(sigma_dB);           %Noise Power=1w
+ndeta = 100;
+scale = 5;
+noise = sigma*[randn(1,N/2-ndeta), scale*randn(1,N/2+ndeta)];
+A = sqrt((scale*sigma)^2 * 10^(SNR/10));    %Target signal amplitude
+T_fix =  sqrt(-sigma^2*log(Pfa));   %fix thresholding
+c = N/40;                             %one side,ref cell = c-guardc
+guardc = 10;                         %guard cell number
+CUTIdx = N/2;                       %position of target
+
+%CFAR mode choose%%%%%,0 CA;1 GO;2 SO;3:OS
+disp("��������������IJ�����     0���� CA-CFAR")
+disp("                           1���� GO-CFAR")
+disp("                           2���� SO-CFAR")
+disp("                           3���� OS-CFAR")
+disp("                           4���� �˳�   ")
+flag=input("�����룺");
+while(flag==0||flag==1||flag==2||flag==3)
+    cfar=flag;
+    %%Simulation of CFAR detection
+    %signal model
+    signal = noise;
+    signal(1,CUTIdx) = signal(1,CUTIdx) + A; %5000��Ŀ��
+    %k = Pfa^(-1/(2*(c-guardc)))-1;
+    T_cfar = ones(1,N);
+    ncell = 0;
+    pn = 0;
+    for j=c+1:N-c
+        a = sum(abs(signal(1,(j-c:j-guardc-1))).^2);
+        b = sum(abs(signal(1,(j+guardc+1:j+c))).^2);
+        if cfar==0
+            pn = a + b;
+            ncell = 2*(c-guardc);
+        end
+        if cfar==1
+            pn = max(a,b);
+            ncell = c-guardc;
+        end
+        if cfar==2
+            pn = min(a,b);
+            ncell = c-guardc;   
+        end 
+        k = Pfa^(-1/ncell)-1;
+        T_cfar(j) =k.*abs(pn);
+    end
+    n_target = 5; %target numbers
+    if cfar==3
+        s = sort(signal);
+        T_cfar = ones(1,N) .* s(1,N-n_target).^2;
+    end
+
+    %traget detected
+    idxC = find(abs(signal).^2 > T_cfar);
+
+    figure;
+    plot(n,10*log(abs(signal).^2),'-o','MarkerIndices',idxC,'MarkerSize',10);
+    hold on;stem(N/2,10*log(abs(signal(1,N/2)).^2),'-p','MarkerEdgeColor','r','MarkerFaceColor','r');
+    hold on;plot(n,10*log(T_cfar));
+    xlim([c+2,N-c-1]);ylim([0,100]);
+    Pfa_cfar = sum(abs(noise(1,c+2:N-c-1)).^2 > T_cfar(1,c+2:N-c-1))./(N-2*c);
+    fprintf('�龯��:%s\n',num2str(Pfa_cfar));
+    disp("��ǰ����ִ�����")
+    disp("��������������IJ�����     0���� CA-CFAR")
+    disp("                           1���� GO-CFAR")
+    disp("                           2���� SO-CFAR")
+    disp("                           3���� OS-CFAR")
+    disp("                           4���� �˳�   ")
+    flag=input('�����룺');
+end
+disp("���˳�����")