1. A method for synthetic aperture radar (SAR) processing comprising: receiving, by use of a processor, a plurality of SAR signals; generating a piecewise approximation of the plurality of SAR signals over a coherent processing interval, wherein the piecewise approximation is a function of a linear fit, an aspect filter, a spatial filter, and a sparsity constraint and mitigates phase reflection components of each SAR signal; and generating an estimate of a scene from the piecewise approximation.