Student research highlight enhanced sonar bathymetry: An echo DOA tracking approach

In this article, we highlight recent advances in adaptive sonar-array processing for three-dimensional (3-D) depth map reconstruction, i.e., bathymetry. Bathymetry reconstruction of underwater environments is of great importance for applications ranging from infrastructure inspection to intrusion detection. Side-scan images, that is, two-dimensional (2-D) images of the backscattered signal amplitude are affected by the layover phenomenon, i.e., superposition of echoes. This phenomenon appears in the presence of tall objects, whenever the pulse emitted by the sonar ensonifies the top of the object before the bottom. In such, the area around the object is not entirely observable and a full 3-D bathymetry reconstruction is necessary. For sidelooking sonar arrays, bathymetry is obtained by triangulating the scatterers corresponding to each range bin, or equivalently, estimating the direction of arrival (DOA) of backscattered echoes.