Comparison of Omega-K and backprojection regarding spatial resolution for squinted spotlight SAR with motion errors

Abstract

The image quality of an image processing technique in a real airborne spotlight Synthetic Aperture Radar scenario mainly depends on its capability of correcting motion error effects. Therefore we compare the frequency domain imaging technique rotated Omega-K with explicit range cell migration correction with the time domain algorithm global Backprojection in their imaging quality by taking motion errors and scene size as well as the squint and the depression angles into account. The numerical investigations show that for a squint angle of 20° and a depression angle of 25° up to a limit of 5m motion error magnitude Omega-K yields good image quality in terms of Integrated Side Lobe Ratio for point targets with 200 m ground range distance to the spot center. For larger motion errors or larger scene sizes the Backprojection algorithm should be used to guarantee image quality with the disadvantage of higher computational costs.