Interferometric transmission synthetic aperture sonar

Synthetic aperture has the potential for an order of magnitude improvement in the cross-range resolution of side-scan imaging sonars. However, two problems have up to now prevented the operational deployment of such systems in the ocean. The first relates to the focusing of the array despite platform wander and sound speed fluctuations, which lead to unknown array and wavefront distortions. The second relates to the limitation of the maximum range and platform velocity, ie, the area mapping rate. This is due to apparition of range or azimuth ambiguities above a critical range and velocity. In this paper, two new patented sonar designs (1), are presented which allow the area mapping rate to be doubled, with respect to that of a conventional synthetic aperture. For the purpose of the presentation, ideal conditions are assumed for platform motion and the medium