Sub-aperture method for the wide-bandwidth wide-angle inverse synthetic aperture radar imaging

In this paper, a method for obtaining focused inverse synthetic aperture radar (ISAR) images of targets based on the radar backscattering measurements taken over wide bands and wide angles. The proposed method divides wide angle and wide frequency band into small aperture bands in the spatial frequency or Fourier domain. This set-up makes it possible to use fast calculation of ISAR images for every sub-aperture data set as in the case of standard ISAR case of small-bandwidth and small-angle. The details of the method are presented and numerical examples are given for the validation the method. The electromagnetic scattering estimation from the target is calculated via a hybrid simulator that uses both the physical optics and the shooting & bouncing ray concepts.