基于压缩感知的脉间捷变频SAR成像研究

Research on Interpulse Frequency Agility SAR Imaging via Compressed Sensing

捷变频技术应用到合成孔径雷达系统中会存在多普勒调频率捷变、方位向无法压缩等问题.在分析捷变频SAR回波相位特性的基础上,本文研究了传统的相关法在方位压缩中的应用;针对相关法效率低、旁瓣高等固有缺陷,考虑到回波信号的稀疏性,提出了基于压缩感知的方位压缩算法,并形成了一种距离压缩采用匹配滤波、方位压缩采用压缩感知的捷变频SAR二维成像方案.仿真实验表明,该方案能克服多普勒调频率捷变等问题,实现捷变频SAR二维成像,并具有低旁瓣、高分辨等优点.

When carrier frequency agility is applied to SAR system,there could be some problems,such as Doppler chirp rate agility,focusout in azimuth, etc. After we analyzed the phase characteristic of radar echo,correlation algorithm was applied to pulse compression in azimuth firstly. Considering the connatural problems of low efficiency and high side lobe level that correlation algo rithm had, pulse compression algorithm based on compressed sensing was presented, which made use of the sparsity of echo signals. Then, a strategy about frequency agility SAR imaging was proposed which involves pulse compression in range based on matching filter and pulse compression in azimuth based on compressed sensing. The results indicate that imaging slrategy can both conquer Doppler chirp rate agility and achieve frequency agility SAR imaging, which has the merit of lower side lobe level and higher reso lution.