Add Radar simulation

2024-05-09 16:48:41 +08:00
parent c57d8588e3
commit 392f83b068
29 changed files with 409 additions and 56 deletions
@@ -0,0 +1,13 @@
+function y = R_d_func(t, range, velocity)
+    global c f_n T_r;
+
+    ti = t - (2 / c) * r(t, range, velocity);
+    p = rem(ti, T_r); % p = t - nT_r
+    n = round((ti - p) / T_r);
+
+    if (n < 0)
+        n = 0;
+    end
+
+    y = R_x_func(t, range, velocity) * exp(1j * -2 * pi * f_n(n + 1) * (t - n * T_r));
+end
@@ -0,0 +1,5 @@
+function y = R_x_func(t, range, velocity)
+    global scatter_coef c;
+    ti = t - (2 / c) * r(t, range, velocity);
+    y = scatter_coef * T_x_func(ti);
+end
@@ -0,0 +1,14 @@
+function y = T_x_func(t)
+    global T_r T_p f_n;
+    p = rem(t, T_r); % p = t - nT_r
+    n = round((t - p) / T_r);
+
+    if (p > T_p)
+        y = 0;
+    elseif (p <= 0)
+        y = 0;
+    else
+        y = exp(1j * 2 * pi * f_n(n + 1) * p);
+    end
+
+end
@@ -0,0 +1,38 @@
+global M N K d epsilon f_c Delta_f c scatter_coef B f_s T_p T_r lambda delta_t max_t range_t len freqs slow_len num_pulse
+
+N = 128; % 脉冲个数
+M = 5; % 频点个数
+K = 10; % 目标个数
+d = 32;
+epsilon = 1e-5; % 误差
+
+f_c = 10e9; % 初始载频 10GHz
+Delta_f = 8e6; % 载频步进间隔 8MHz
+% c = 299792458; % 光速
+c = 3e8;
+scatter_coef = 0.3; % 目标散射强度
+
+B = 64e6; % 带宽 64MHz
+% B_0 = 1e9;
+
+T_p = 1e-6 / 3; % 单载频脉冲下的采样周期 / 脉冲宽度
+f_s = 100 / T_p; % 快时间采样率
+T_r = T_p * 6;
+
+lambda = c / f_c; % 雷达工作波长
+
+% 仿真时间
+num_pulse = 180;
+delta_t = 1e-2 * T_p;
+max_t = num_pulse * T_r;
+range_t = 0:delta_t:max_t - delta_t;
+len = round(max_t / delta_t);
+
+freqs = ((0:len - 1) * f_s) / len;
+
+% 绘图
+figure_flag_1 = false;
+figure_flag_2 = false;
+figure_flag_3 = false;
+
+slow_len = 1e4;
@@ -0,0 +1,22 @@
+function [range, range_idx] = get_range(s_T, s_R, r_0)
+    global T_r delta_t len c range_t;
+
+    % 只取第一个 T_r 的数据计算
+    range_N = T_r / delta_t;
+    s_T_first = [s_T(1:range_N), zeros(1, len - range_N)];
+    s_R_first = [s_R(1:range_N), zeros(1, len - range_N)];
+
+    s_T_fft = fft(s_T_first, len);
+    s_R_fft = fft(s_R_first, len);
+
+    % 发射信号和回波信号做相关
+    p = ifft(s_R_fft .* conj(s_T_fft));
+    norm_p = real(p).^2 + imag(p).^2;
+    [~, range_idx] = max(norm_p);
+
+    range = range_t(range_idx) * c / 2;
+    % fprintf("predict range = %f\n", range);
+    % fprintf("origin range = %f\n", r_0);
+    % fprintf("err = %f\n", range - r_0);
+    % fprintf("\n");
+end
@@ -0,0 +1,47 @@
+function velocity = get_velocity(s_T, s_R, origin_velocity)
+    global T_r delta_t c f_c max_t slow_len;
+    freq_s_T = 1 / T_r;
+
+    slow_freqs = ((0:slow_len - 1) * (1 / T_r)) / slow_len;
+    range_t_slow = 1:slow_len;
+
+    num_slow = max_t / T_r;
+    s_R_slow = zeros(1, slow_len);
+    k = floor(T_r / delta_t);
+
+    idx = 1;
+
+    while abs(s_R(idx)) == 0
+        idx = idx + 1;
+    end
+
+    for i = 0:num_slow - 1
+
+        while abs(s_R(idx + i * k)) == 0
+            idx = idx + 1;
+        end
+        s_R_slow(i + 1) = s_R(idx + i * k);
+    end
+
+    s_R_fft = fft(s_R_slow);
+    [~, max_index_s_R] = max(s_R_fft);
+    freq_s_R = slow_freqs(max_index_s_R);
+
+    % figure(2);
+    % subplot(2, 1, 1);
+    % plot(range_t_slow, abs(s_R_slow));
+    % title(sprintf('s_R'));
+    % subplot(2, 1, 2);
+    % plot(slow_freqs, abs(s_R_fft));
+    % title(sprintf('s_R_fft, freq = %E', freq_s_R));
+    % xlabel('频率 (Hz)');
+
+    f_d = freq_s_T - freq_s_R;
+    velocity = (c * f_d) / (2 * f_c);
+
+    fprintf("predict velocity: %f\n", velocity);
+    fprintf("origin velocity: %f\n", origin_velocity);
+    fprintf("err = %f\n", velocity - origin_velocity);
+    fprintf("\n");
+
+end
@@ -0,0 +1,86 @@
+%%
+clc;
+clear;
+
+config_parameters;
+
+range = [250, 140, 167, 128, 12];
+velocity = [16, 76, 155, 125, 463];
+
+global C_n f_n;
+C_n = zeros(M, len);
+f_n = zeros(M, len);
+
+for n_idx = 1:M
+
+    for t_idx = 1:len
+        C_n(n_idx, t_idx) = floor(rand * (M - 1));
+        f_n(n_idx, t_idx) = f_c + C_n(n_idx, t_idx) * Delta_f;
+    end
+
+end
+
+T_x = zeros(M, len);
+R_x = zeros(M, len);
+R_d = zeros(M, len);
+
+for n_idx = 1:M
+
+    for t_idx = 1:len
+        t = range_t(t_idx);
+        T_x(n_idx, t_idx) = T_x_func(t);
+        R_x(n_idx, t_idx) = R_x_func(t, range(n_idx), velocity(n_idx));
+        R_d(n_idx, t_idx) = R_d_func(t, range(n_idx), velocity(n_idx));
+    end
+
+end
+
+save temp.mat
+
+%%
+
+clc
+clear
+load temp.mat
+
+pred_range = zeros(1, M);
+range_idx = zeros(1, M);
+pred_velocity = zeros(1, M);
+
+for n_idx = 1:M
+
+    [pred_range(n_idx), range_idx(n_idx)] = get_range(T_x(n_idx, :), R_x(n_idx, :), range(n_idx));
+    pred_velocity(n_idx) = get_velocity(T_x(n_idx, :), R_x(n_idx, :), velocity(n_idx));
+
+end
+
+%%
+r_range = 1:500;
+v_range = 1:500;
+
+[X, Y] = meshgrid(r_range, v_range);
+pred_z = zeros(length(r_range), length(v_range));
+origin_z = zeros(length(r_range), length(v_range));
+
+for n_idx = 1:M
+    pred_z(round(pred_range(n_idx)), round(pred_velocity(n_idx))) = 1;
+    origin_z(round(range(n_idx)), round(velocity(n_idx))) = 1;
+end
+
+figure(1)
+subplot(211);
+mesh(X, Y, pred_z);
+title("Predict range-velocity reconstruction under M = 5");
+xlabel("Range (m)");
+ylabel("Velocity (m/s)");
+
+subplot(212);
+mesh(X, Y, origin_z);
+title("Origin range-velocity data under M = 5");
+xlabel("Range (m)");
+ylabel("Velocity (m/s)");
+
+
+
+
+
@@ -0,0 +1,3 @@
+function x = r(t, range, velocity)
+    x = range + velocity * t;
+end