雷达信号检测.zip_信号检测算法_动目标检测_雷达 对消_雷达检测_雷达算法

function [] = detection_function(fr, fd1, fd2, M, N, n_reference, n_protect, alpha) % This function shows the radar signal processing in MTI, MTD and CFAR. % MTI is 3-pulse canceller, and MTD is N-point FFT, and then the GOCACFAR % shows the result. % fr ----------------------------- PRF % fd1 ---------------------------- doppler frequency of moving target1 % fd2 ---------------------------- doppler frequency of moving target2 % M ------------------------------ number of range point % N ------------------------------ number of tr % n_reference -------------------- number of CFAR reference unit % n_protect -------------------- number of CFAR protect unit % alpha -------------------------- CFAR threshold factor if nargin ~= 8 error('The number of input argument should be 8.'); end %------------------------------参数设置------------------------------------------------------------------------------------------------------ fr = 200; % PRI（Hz） tr = 1 / fr; % 导前周期，即脉冲重复周期（s） fd1 = 90; % 动目标1的多普勒频移（Hz） fd2 = 140; % 动目标2的多普勒频移（Hz） M = 6700; % 回波信号的距离点数 N = 10; % 导前周期数 n_reference = 11; % CFAR待检单元每侧的参考单元数 n_protect = 2; % CFAR待检单元每侧的保护单元数 alpha = 2.9; % CFAR门限因子 %-----------------------------生成N个导前周期，每个导前周期含M个距离点的复数据，其中只包含动目标，无杂波------------------------------------------ for m = 1 : N moving_target1(m) = 10 * exp(j * 2 * m * pi * fd1 * tr); % 第m个导前周期，动目标1在某距离点内的复数据 moving_target2(m) = 10 * exp(j * 2 * m * pi * fd2 * tr); % 第m个导前周期，动目标2在某距离点内的复数据 end x = ones(1, 3); % 每个动目标占据三个距离点 n = length(x); for m = 1 : N sequence(m, :) = [[zeros(1, 1700), x, zeros(1, 3400 - 1700 - n)] * moving_target1(m), [zeros(1, 1600), x, zeros(1, M - 3400 - 1600 - n)] * moving_target2(m)]; % 第m个导前周期，令动目标1占据1701、1702和1703三个距离点，令动目标2占据第5001、5002和5003三个距离点 end %------------------------------生成杂波，并将其加入到各个周期的数据序列，形成回波混合信号-------------------------------------------------------- for m = 1 : N clutter_i(m, :) = randn(1, M); clutter_q(m, :) = randn(1, M); clutter(m, :) = 0.5 * (clutter_i(m, :) + j * clutter_q(m, :)); % 杂波 end for m = 1 : N mix_signal(m, :) = sequence(m, :) + clutter(m, :); % 生成混合信号 end %------------------------------三脉冲对消（MTI）---------------------------------------------------------------------------------------------- for m = 1 : N - 2 mti(m, :) = mix_signal(m, :) - 2 * mix_signal(m + 1, :) + mix_signal(m + 2, :); % 三脉冲对消运算 end %------------------------------FFT运算（MTD）------------------------------------------------------------------------------------------------ for n = 1 : M mtd(:, n) = fft(mti(:, n) .* hamming(N - 2, 'periodic'), N - 2); % N-2点FFT运算 end mtd_amplitude = abs(mtd); % MTD各通道直接输出模值 set(0, 'defaultfigurecolor', 'w'); for m = 1 : N - 2 figure(m + 5); plot(mtd_amplitude(m, :), 'r'); grid on; xlim([0, M]); xlabel('距离点'); title(['MTD第 ' num2str(m - 1) ' 通道输出结果']); end %-----------GOCA CFAR--------------------------------------------------------------------------------------------------- for m = 1 : N - 2 % 分别对MTD N-2个通道内的距离点做过门限检测 z = mtd_amplitude(m, :); for n = 1 : 1 + n_protect % 待检单元 b2(n) = mean(z(n + 1 + n_protect : n + n_protect + n_reference)); % 待检单元右侧的参考窗求均值 d(n) = b2(n); end for n = 1 + n_protect + 1 : n_reference + n_protect + 1 b1(n) = mean(z(1 : n - 1 - n_protect)); % 待检单元左侧的参考窗求均值 b2(n) = mean(z(n + 1 + n_protect : n + n_protect + n_reference)); d(n) = max(b1(n), b2(n)); % 两侧参考窗均值选大 end for n = 1 + n_reference + n_protect + 1 : M - n_reference - n_protect b1(n) = mean(z(n - n_protect - n_reference : n - 1 - n_protect)); b2(n) = mean(z(n + 1 + n_protect : M)); d(n) = max(b1(n), b2(n)); end for n = M - n_reference - n_protect + 1 : M b1(n) = mean(z(n - n_protect - n_reference : n - 1 - n_protect)); b2(n) = mean(z(n + 1 + n_protect : M)); d(n) = max(b1(n), b2(n)); end s_cfar = zeros(1, M); for n = 1 : M T(n) = alpha * d(n); % 第n个距离点的检测门限 if z(n) > T(n) % 过门限 s_cfar(n) = z(n) - T(n); % 将该距离点的数据置为差值 end end temp(m, :) = s_cfar; % 存储各个通道的检测结果 figure(m + 40); plot(z, 'r'); hold on; plot(T, 'g'); xlabel('距离点'); grid on; xlim([0, M]); title(['MTD第 ' num2str(m - 1) ' 通道的门限设定']); legend('混合信号', '门限'); figure(m + 80); hold off; plot(s_cfar, 'r'); xlabel('距离点'); grid on ; xlim([0, M]); title(['MTD第 ' num2str(m - 1) ' 通道检测结果']); end for n = 1 : M cfar(:, n) = max(temp(:, n)); % 取N-2个通道中的最大值作为该距离点的检测结果 end figure(115); plot(cfar, 'r'); title('GOCA CFAR检测结果'); xlabel('距离点'); xlim([0, M]); grid on ;