Extensions to the step transform SAR processing technique

In previous descriptions of the step transform SAR azimuth compression algorithm, it has been assumed that the azimuth signal is linear FM and is strictly confined within a single range cell. These conditions do not always hold. Under stringent imaging conditions range curvature occurs, i.e., a nonlinear range migration of the energy associated with a point target takes place. If the system must also operate at a high squint angle, the azimuth signal becomes nonlinear FM. This paper describes extensions to the basic step transform algorithm that allow these imaging situations to be accommodated.