Using the holographic property of synthetic aperture sonar images to enable real aperture sonar navigation.

Abstract

Synthetic aperture sonar (SAS) images contain broadband multiaspect information about a scene; this leads to several holographic properties. The most commonly understood property is that a complete image can be reconstructed at lower resolution from any subband of the Fourier transform; this effect is used for speckle reduction. A less commonly understood property is that a SAS image contains all possible real aperture images over some range of angles and frequencies. This allows real aperture images to be coherently correlated with SAS images. The ability to coherently correlate sonar images permits the use of a broad class of probabilistic feature-based navigation algorithms. This paper describes the method of coherently correlating SAS and real aperture images for navigation, and presents results from St. Andrew Bay and the Gulf of Mexico using the small synthetic aperture minehunter.