Focusing Synthetic Aperture Sonar (SAS) data with the Omega-K technique

Abstract

Synthetic Aperture Radar (SAR) and Sonar (SAS) systems provide high resolution reflectivity maps of the imaged scene by coherently combining the echoes collected along a virtual array of receivers. A peculiarity of SAS systems is that the echoes are often collected by moving a short real array of hydrophones to avoid range ambiguity. In this paper we present a modification of the standard wavenumber focusing algorithm widely used in SAR data processing to make it suitable for focusing bi-static SAS data. An autofocusing technique is then exploited to estimate and compensate for the deviation of the platform trajectory from the rectilinear one.