window_len = 64; % 窗口长度 N_guard = 16; % 保护间隔 N_train = 32; % 训练窗口长度 threshold = 3; % 判决门限 [range_indices, doppler_indices] = cfardetect(echo_mti, window_len, ... N_guard, N_train, threshold); range = range_indices * c / (2*fs) * lambda / 2; % 目标距离 doppler = (doppler_indices - n/2 - 1) * fs / n; % 目标多普勒频移中的cfardetect的代码是什么

cfardetect的代码如下：

function [range_indices, doppler_indices] = cfardetect(echo_mti, window_len, N_guard, N_train, threshold)
    [n, m] = size(echo_mti);
    RDM = zeros(n - N_guard - N_train + 1, m - window_len + 1);
    for i = 1:n - N_guard - N_train + 1
        for j = 1:m - window_len + 1
            train = echo_mti(i:i+N_train-1, j:j+window_len-1);
            train_fft = fft(train, [], 2);
            train_pow = abs(train_fft).^2;
            guard = echo_mti(i+N_train+N_guard:i+N_train+N_guard+N_train-1, j:j+window_len-1);
            guard_fft = fft(guard, [], 2);
            guard_pow = abs(guard_fft).^2;
            threshold_pow = threshold * mean(guard_pow, 1);
            RDM(i, j) = max(max(train_pow, [], 1) - threshold_pow);
        end
    end
    [doppler_indices, range_indices] = find(RDM);
end

其中，echo_mti是经过MTI（移动目标指示）处理后的回波信号，window_len是窗口长度，N_guard是保护间隔，N_train是训练窗口长度，threshold是判决门限。函数的输出是range_indices和doppler_indices，分别对应目标距离和多普勒频移的索引值。