Efficient SAS image-reconstruction algorithms

Abstract

Now that several prototype strip-map synthetic aperture sonar (SAS) systems are in operation and producing images (albeit on an irregular basis), much of the focus of current research is on the efficiency of the various strip-map image reconstruction algorithms. Although sometimes still used by several sonar groups, the old ‘‘delay-and-sum’’ beamforming, or exact algorithm, is clearly inadequate for high throughput imaging. Newer algorithms such as the range/Doppler, wave number, and chirp-scaling algorithms are considered. Using a simulated target field of point reflectors, the results from all of these algorithms are compared and the relative computational loads given. As well, the more recently developed (em accelerated) chirp-scaling algorithm is explained.