Autofocus in fast factorized backprojection for processing of SAR images when geometry parameters are unknown

This paper introduces a new autofocus method for high-resolution SAR systems. The new method relies on varying antenna path parameters, i.e. the cause of the focusing problem. The variation and determination of antenna path parameters is computed and structured by incorporating the method into the framework of fast factorized backprojection, and thus also blending deterministic focus and autofocus into one method. The new autofocus has been tested with wavelength-resolution SAR data with good results.