UAV-SAR Motion Compensation And Imaging Algorithm

SAR can achieve high-resolution imaging of the ground and is capable ofobtaining radar image similar to optical images. SAR is with the characteristics ofworking all-time and all-weather. UAV is a new platform for SAR and has beenresearched widely. Strip map mode and spotlight mode are the two main modes of SAR.The long dwell time on the target helps the spotlight SAR, the main mode for the highresolution imaging of SAR, obtain high resolution image of the illuminated area.This thesis focuses on radar imaging and motion compensation under theresolution requirement of0.05m×0.05m. There are several contributions in this thesis:(1) Range resolution and azimuth resolution of SAR are discussed; strip map modeand spotlight mode of SAR are compared and analyzed.(2) The PFA imaging algorithm of spotlight SAR is analyzed in detail, aiming toimaging under the resolution of0.05m×0.05m, data missing in limited extent isappeared when the interpolation is operated in range direction, and the explanation isgiven. One method of decreasing the dechirping bandwidth in range direction ispresented to minish the variation range of the waves in rage direction and avoids thedata missing under the interpolation operation in range direction, which ensures theachievement of imaging simulation under the resolution requirement of0.05m×0.05mbased on PFA algorithm.(3) The influence of motion error on SAR echo data is analyzed. Simulation resultsof0.05m×0.05m resolution images are showed after investigating two algorithms ofMD and PGA. Aiming to the resolution requirement of0.05m×0.05m and, consideringthe features of unmanned airborne SAR, resolution requirement of0.05m×0.05m, theinfluence of range migration on SAR imaging, one modified motion compensationmethod is proposed to achieve high resolution UAV-SAR imaging through correctingrange migration and phase error.To sum up, this thesis studies high resolution UAV-SAR imaging and motioncompensation algorithms under the resolution requirement of0.05m×0.05m. Based thePFA imaging algorithm, presents solutions solving the imaging problems of missing data in imaging of0.05m×0.05m resolution and one modified motion compensationmethod, at last verifies these solutions through simulation.