Study Of Real-time Signal Processing System Of High Resolution Of Airborne Spotlight SAR

Synthetic Aperture Radar (SAR) imaging has been a new trend of radar, and SAR imaging has the characteristics of all-weather, day/night, long range and high-resolution. Since the invention of SAR in 1950s, it has had great development. The airborne SAR has been widely used and the space-borne SAR has already been applied in some areas.The paper focuses on how to implement the spotlight SAR imaging algorithm in hardware. The algorithm is an effective imaging modality for high resolution imaging. By controlling the antenna beam pointing, the spotlight SAR imaging makes the radar exposure to a specific area of the ground for a long time., resulting in higher azimuth resolution. The spotlight SAR imaging mode is very similar to rotating target imaging mode. Polar format algorithm of Spotlight SAR imaging is borrowed from the rotating polar target imaging algorithm. Motion Compensation (MOCO) is necessary for SAR due to the instability of the movement of platform. So Chapter 2 introduces the MOCO algorithm in spotlight SAR imaging mode. Chapter 3 treats the structure of SAR real-time imaging system, which is composed of a storage board and a signal processing board. Chapter 4 is the emphasis of the paper, mainly discussing the software implementation of spotlight SAR imaging system. Tasks are reasonably distributed to each board and processing unit on the basis of the analysis of high resolution airborne spotlight SAR system and the corresponding algorithm. Implemented by mixed programming of C and Assembly language, as well as the computing on FPGA, the DSP software is of high efficiency and reliability. In the end the shortage of present research as well as some discussion on the future research work is presented.