Time frame selection for High PRF Pulsed Doppler radar ISAR image formation

Inverse Synthetic Aperture Radar is a signal processing technique used to obtain high resolution images of targets. In ISAR imaging high cross-range resolution is obtained by exploiting the radar to target relative motion. The radar target kinematic affects the data grid spacing and shape in the Fourier domain (acquisition surface). When the grid is rectangular with equally spaced points, the ISAR image is focussed and it has predictable resolution properties. The object of this paper is to investigate the relationships between the acquisition surface and both the resolution and defocusing properties of the ISAR image given the radar-target kinematic. A distortion parameter that depends on the kinematic properties is defined and compared to image focus quality indicators. Simulation results are also shown considering a complex target model.