Subspace intersection method of bearing estimation in shallow ocean using acoustic vector sensors

The subspace intersection method (SIM) provides asymptotically unbiased bearing estimates of multiple acoustic sources in a range-independent shallow ocean using a one-dimensional search without prior knowledge of source ranges and depths. The original formulation of this method is based on deployment of a horizontal linear array of hydrophones which measure acoustic pressure. In this paper, we extend SIM to an array of vector sensors which measure acoustic pressure as well as all components of particle velocity. Use of vector sensors reduces the minimum number of sensors required by a factor of 4, and also eliminates the constraint that the intersensor spacing should not exceed half wavelength. The performance enhancement due to the additional information provided by the vector sensors is illustrated through simulation results.