Multibeam sonar image matching for terrain-based underwater navigation

This paper presents a terrain-referenced method for positioning an underwater vehicle equipped with a multibeam sonar. The local bathymetric profiles provided by this sensor are matched with a digital elevation map (DEM). The absolute position and heading of the vehicle with respect to this reference map are estimated by correlating a part of this map with the on-line altitude measurements. We propose an extended approach to the classical matching methods that takes into account the non-regular sampling of sonar data in the correlation space. This technique has been successfully applied to real terrain data obtained from the Var underwater canyon (France)