Minimum entropy autofocus for 3D SAR images from a UAV platform

Abstract

Newly developed platforms such as unmanned aerial vehicles (UAVs) offer significant potential for broadening the application of synthetic aperture radar (SAR) methods. Position and orientation uncertainties associated with such systems result in a loss of pulse coherence, leading to degradation of the resulting imagery. Building on recent efforts in the development of algorithmic autofocus methods, here we develop a variational autofocus technique for limited aperture, three dimensional SAR image formation. The method is based in the minimization of the image entropy. Results are demonstrated in the context of a UAV SAR under development at Tufts and MIT Lincoln Laboratory.