High resolution bearing estimation in partially known ocean using short sensor arrays

All currently known methods of bearing estimation in ocean, such as SIM and R-MUSIC, require deployment of long sensor arrays. The minimum number of sensors is proportional to the number of normal modes ~ (ocean depth/wavelength). It is shown in this paper that high - resolution bearing estimation can be achieved with shorter arrays by using a truncated normal mode expansion of acoustic field in the ocean. The proposed approach has the following additional advantages: (1) reduced need for knowledge of channel parameters, and (2) lower computational complexity.