A novel parametric SAR autofocus method

Abstract

In synthetic aperture radar (SAR), low scene-contrast may invalidate most of the existing autofocus methods, and the limited autofocus performance is also difficult to verify. Based on a parametric statistical signal model in the coherent processing interval (CPI) of SAR, a novel SAR autofocus method is developed and it is especially applicable to extremely low-contrast scenes. Furthermore, the limitation of CPI length and the Cramer-Rao low bound of the autofocus parameter estimation are all analytically obtained. Finally, real measurement data is also exploited to validate the proposed model and the new method.