Slant range and cross range correction for polar format distortion in ISAR imaging

The authors describe a focusing procedure, for use in step-frequency ISAR imaging, which corrects for the assumption of a rectangular data sampling grid; searches for focused images can be shortened using a two stage procedure. The first stage of processing constructs an intermediate image from which slant range blurring is removed, The second stage removes the slant range dependent, cross range blurring by phase correction of the slant range profile. Example images using simulated data are used to illustrate results from each stage of the processing. An example using experimental data is also shown