基于matlab的一维CA-CFAR算法实现恒虚警

clc; clear; close all; warning off; addpath(genpath(pwd)); Fs = 1000; % Sampling frequency T = 1/Fs; % Sampling period L = 1500; % Length of signal t = (0:L-1)*T; % Time vector % Form a signal containing a 50 Hz sinusoid of amplitude 0.7 and a 120 Hz % sinusoid of amplitude 1. S = 0.7*sin(2*pi*50*t) + sin(2*pi*120*t); % Corrupt the signal with zero-mean white noise with a variance of 4 X = S + 2*randn(size(t)); X_cfar = abs(X); % Data_points Ns = 1500; % let it be the same as the length of the signal % Targets location. Assigning bin 100, 200, 300, and 700 as Targets % with the amplitudes of 16, 18, 27, 22. X_cfar([100 ,200, 300, 700])=[16 18 27 22]; % plot the output figure(1); tiledlayout(2,1) nexttile plot(X_cfar) % Apply CFAR to detect the targets by filtering the noise. % TODO: Define the number of Training Cells T = 12; % TODO: Define the number of Guard Cells G = 4; % TODO: Define Offset (Adding room above noise threshold for the desired SNR) offset = 5; % Initialize vector to hold threshold values threshold_cfar = zeros(Ns-(G+T+1),1); % Initialize Vector to hold final signal after thresholding signal_cfar = zeros(Ns-(G+T+1),1); % Slide window across the signal length for i = 1:(Ns-(G+T+1)) % TODO: Determine the noise threshold by measuring it within % the training cells noise_level = sum(X_cfar(i:i+T-1)); % TODO: scale the noise_level by appropriate offset value and take % average over T training cells threshold = (noise_level/T)*offset; % Add threshold value to the threshold_cfar vector threshold_cfar(i) = threshold; % TODO: Measure the signal within the CUT signal = X_cfar(i+T+G); % add signal value to the signal_cfar vector signal_cfar(i) = signal; end % plot the filtered signal plot(signal_cfar); legend('Signal') % plot original sig, threshold and filtered signal within the same figure. nexttile plot(X_cfar); hold on plot(circshift(threshold_cfar,G),'r--','LineWidth',2) hold on plot (circshift(signal_cfar,(T+G)),'g--','LineWidth',2); legend('Signal','CFAR Threshold','detection')