Study Of SAR Imaging Autofocus Algorithm

Synthetic aperture radar(SAR) enhances radar's information acquisition capability and information awareness ability by obtaining high resolution imageries. Now,SAR has been widely used in airborne radar system as a new function of modern radar. Especially for litter airborne SAR platform flying at middle and low height, Its flight path and motion attitudes are hardly controlled in the influence of airflow during the period of recording data. After traditional motion compensation, surviving phase error need to be estimated and compensated automatically in high resolution SAR imaging process to obtain well focused image.Studying the technology of SAR is usually based on SAR imaging. They are necessary to SAR imaging comprehending the theory of SAR and applying SAR imaging algorithm. The theory of SAR is introduced from physical concept and SAR imaging processing using simulated data. Then common SAR imaging algorithms are discussed.Autofocus is one of the key steps in the signal processing of a SAR system. SAR image autofocus algorithm based on SAR echo is mainly studied in this dissertation. Three novel autofocus algorithms is presented in this dissertation after classical autofocus algorithms is introduced briefly, which are based on maximum total variation, DCT and sub-space projection technique respectively. The performance of the algorithms is analyzed by simulation data .And the measured data show the validity of the method.