In synthetic aperture radar (SAR), many adverse conditions may cause errors in the raw phase-history data. Autofocus methods are commonly used in SAR to mitigate the effects of these problems. Over the years, many types of autofocus have algorithms have been created, however, each has implicit assumptions restricting their use. The backprojection image formation algorithm places few restrictions on SAR imaging, thus it is desirable to have an autofocus algorithm that is similarly unconstrained. This paper presents a versatile autofocus method that is accordant with backprojection
