SAR方位向成像matlab代码及注释

以下是SAR方位向成像的matlab代码及注释：

% SAR方位向成像

%% 读取数据

% 读取SAR数据
filename = 'sar_data.h5';
data = h5read(filename, '/data');
% 读取SAR参数
inc_angle = h5readatt(filename, '/', 'inc_angle');
range_res = h5readatt(filename, '/', 'range_res');
chirp_rate = h5readatt(filename, '/', 'chirp_rate');
pulse_dur = h5readatt(filename, '/', 'pulse_dur');
c = h5readatt(filename, '/', 'c');
% 计算SAR参数
lambda = c / (2 * chirp_rate);
range_max = size(data, 1) * range_res;
range_axis = linspace(0, range_max, size(data, 1));
doppler_axis = linspace(-1/2/pulse_dur, 1/2/pulse_dur, size(data, 2));
doppler_bandwidth = abs(doppler_axis(end) - doppler_axis(1));
% 设置图像范围
range_lim = [0, range_max];
doppler_lim = [-doppler_bandwidth/2, doppler_bandwidth/2];

%% 调整数据

% 对SAR数据进行调整
data = fftshift(fft(data, [], 2), 2);

%% 校正斜视效应

% 计算斜视角
look_angle = asin(c * doppler_axis / (2 * chirp_rate));
% 计算校正系数
slant_range = sqrt(range_axis.^2 + (c * pulse_dur / 2).^2);
range_correction = slant_range * cos(look_angle) - range_axis;
doppler_correction = -2 * chirp_rate * slant_range / c .* sin(look_angle);
phase_correction = exp(-1i * 4 * pi / lambda * range_correction .* doppler_correction);
% 对SAR数据进行校正
data = data .* phase_correction;

%% SAR方位向成像

% 计算距离和角度矩阵
[R, A] = meshgrid(range_axis, look_angle);
% 计算方位向分辨率
azimuth_res = lambda / 2 / sin(inc_angle);
% 计算方位向采样率
azimuth_sampling_rate = range_res / azimuth_res;
% 生成方位向采样点
azimuth_axis = linspace(-pi/2, pi/2, size(data, 2) * azimuth_sampling_rate);
% 计算方位向校正系数
azimuth_correction = exp(-1i * 2 * pi / lambda * R .* sin(A) .* azimuth_axis);
% 对SAR数据进行方位向成像
image = ifftshift(ifft(data .* azimuth_correction, [], 2), 2);

%% 显示结果

% 显示SAR数据
figure;
imagesc(doppler_axis, range_axis, abs(data).^2);
xlabel('Doppler (Hz)');
ylabel('Range (m)');
axis image;
axis([doppler_lim, range_lim]);
colorbar;
title('SAR Data');

% 显示校正斜视效应后的SAR数据
figure;
imagesc(doppler_axis, range_axis, abs(data).^2);
xlabel('Doppler (Hz)');
ylabel('Range (m)');
axis image;
axis([doppler_lim, range_lim]);
colorbar;
title('SAR Data (Slant Range Corrected)');

% 显示SAR方位向成像结果
figure;
imagesc(azimuth_axis * 180 / pi, range_axis, abs(image).^2);
xlabel('Azimuth (degree)');
ylabel('Range (m)');
axis image;
axis([-90, 90, range_lim]);
colorbar;
title('SAR Image');