合成孔径雷达图像的自适应旁瓣抑制算法分析和实验研究

The Analyzation of SAR Image Adaptive Sidelobe Reduction Algorithms and Experiments

合成孔径雷达是有源相干高分辨率成像系统 ,常规成像算法对接收数据进行二维匹配滤波 ,实现成像。由于成像系统的二维频域支持域有限 ,使成像系统的方位向和距离向脉冲响应为 sinc函数 ,又 SAR图像具有动态范围大的特点 ,使 SAR图像中的强目标旁瓣使弱目标主瓣发生畸变 ,所以要对 SAR图像进行旁瓣抑制。讨论并比较了两种自适应旁瓣抑制算法 ,并利用模拟数据和中科院电子所的 L- SAR系统的雷达图像对这两种算法进行了实验研究。

Synthetic aperture radar is an active coherent high resolution imaging system. The classical imaging algorithms process the SAR received data by matched filter in two-dimensional frequency domain, and get reconstructed SAR images. In classical imaging algorithms, Fast Fourier Transform is used broadly. Because of the limited frequency domain support of the SAR systems, the system impulse responses in the range and azimuth directions are sinc functions. And the SAR images have great dynamic domain. The ratio of the returned power between the bright and the weak targets reached 50 dB, even higher. The sidelobe of a bright point target can easily obscure and violate the mainlobe of weaker points. So SAR images often demands sidelobe reduction. The conventional sidelobe reduction applies the fixed weighting functions on the whole aperture data, and the conventional weighting approach have to compromise between the degree of sidelobe reduction and imaging resolution. In this paper discusses two adaptively sidelobe reduction algorithms, and compared their processing results with conventional sidelobe reduction methods by the simulated data and the IECAS L\|SAR system raw data.