Synthetic aperture bathymetry estimation with a multielement array

Bathymetric estimation from multiple synthetic aperture sonar (SAS) images is challenging for shallow water environments with low frequencies. This is due to the multipath echoes corrupting the desired direct-path echoes. In an attempt to suppress some of these multipaths, the MUD synthetic aperture sonar developed at TNO has a sixteen element vertical hydrophone array. In this paper we consider a number of different bathymetry estimation techniques using multielement vertical arrays. We introduce an ad-hoc multilook variant of the matrix pencil method and find that it outperforms beamformed interferometry, extending the range of useful bathymetry until the problematic multipath mode produces a similar angle of arrival that cannot be resolved.