几种提高分布式雷达方位向分辨率方法的分析与比较

Analysis and Comparison of Several Algorithms on Improving Azimuth Resolution for Distributed SAR

分析比较了三种提高分布式合成孔径雷达方位向分辨率的方法:时域扩频,展宽等效多普勒带宽,分辨率虽有提高,但存在频谱混叠,影响成像效果;提高频谱利用率,实现全孔径成像,达到理论分辨率,但多普勒分量提取以及模糊抑制的计算量过大;利用统计分析及估计理论对成像进行空域滤波虽然扩展了清晰成像面积,但没有提高绝对分辨率,且由于矩阵的伪逆操作,计算量惊人。针对上述算法的不足,借鉴扩频思想,提出空间频率滤波方法以改善合成信号的频域特性,从而提高方位向分辨率。给出了仿真结果以说明所提出方法的有效性。

We analyzed three existing methods for improving azimuth resolution for distributed SAR system in this paper： to extend equivalent Doppler spectrum in time domain, which improves resolution while leads to spectrum overlapping and worsen results; to improve spectrum utilization and realize full-aperture imaging, which results in considerable computational complexity; to carry out spatial filtering by means of statistics and estimation, which enlarges imaging area while maintains theoretical resolution and results in amazing computational complexity for pseudo-inverse of matrix. In view of the shortcomings of these methods, we proposed a spatial frequency filtering approach to improve the synthesized spectrum to overcome them. We presented computer simulations to validate the proposed method.