Synthetic Aperture Radar Imaging Algorithm Research

Synthetic Aperture Radar (SAR) is a sort of high resolution imaging radar. Using SAR we can obtain radar images independent of all time, all weather, and long distance conditions, it provide multi-bands, huge-range observation and high resolution image. SAR plays a key role in military and civil applications.As a member in SAR family, ISAR which is applied to detect and image moving target is different from traditional SAR. Traditional SAR is used for stationary target imaging by moving itself while ISAR is always static.First of all, the basic theory of ISAR is summarized in this paper. Then the imaging algorithm based on 2-D turntable imaging principle of ISAR is analyzed and the formulations of Range-Doppler FFT algorithm are given. To improve the quality of ISAR image, the impact of window function has also been investigated. Then on the basis of monostatic imaging, the 2-D turntable imaging principle of bistatic ISAR is studied, and the small rotation angel imaging is analyzed.The basic theory of SAR imaging including squint SAR is also introduced and discussed in this paper. The Chirp Scaling Algorithm (CSA) is presented to obtain precise object image. The nonlinear Chirp Scaling algorithm (NCSA) is investigated for squint SAR imaging. The differences between CSA and NCSA are discussed and summarized at the end of this paper.