一种星载高分辨率SAR的非基带插值方位预处理方法

A method of non baseband interpolation preprocessing in azimuth for spaceborne high-resolution SAR

星载高分辨率滑动聚束SAR系统采用方位向大转角技术来实现高分辨率与宽测绘带的折中,系统在大转角时场景回波的距离徙动非常大,单一回波窗无法适应大距离徙动。基于这一问题本文提出一种非基带插值方位预处理方法,系统采用分段变重频技术实现对回波的全覆盖。通过二维时域对回波沿方位向分块,采用非基带插值对分段后的时域信号进行重采样,得到不同PRF下的均匀化数据。仿真结果表明,该方法有效实现了数据的均匀化预处理,与传统处理方法相比成像结果的方位分辨率提高,PSLR、ISLR得到4 d B以上的改善。

Azimuth large angle technology is used for striking balance between high resolution and wideswath in space-borne high resolution sliding spotlight SAR system. Echo window cannot adapt to thelarge range migration which come from large angle scenario. In order to solving this problem, apreprocessing method of non baseband interpolation in azimuth is presented in this paper. The segmentedvariable frequency technology is applied for full coverage of the echo in the system. According to theazimuth,two dimensional time domain is used for dividing the echo. Non baseband interpolation isapplied for re-sampling the segmented time domain signal, and homogenized data is achieved underdifferent PRF. Simulation results show that this method is effective in pre-proeessing data uniformly.Compared with traditional methods, the azimuth resolution is improved,PSLR and ISLR of imagingresults are all improved above 4 dB.