Two-Step Azimuth and Elevation Angle Estimation with Vector Hydrophone Array

This paper proposes a new 2D direction finding algorithm using vector hydrophone array. A vector hydrophone comprises of two or three velocity hydrophones plus an optional pressure hydrophone, all spatially co-located in a point-like geometry. The velocity hydrophones are identical but orthogonally oriented, measuring one Cartesian component of the incident sonar wave-field's velocity-vector. The pressure hydrophone measures the acoustic pressure in the wavefield. The proposed algorithm realizes the 2D direction estimation via two steps. In the first step, a pressure-particle-velocity field vector smoothing root-MUSIC algorithm is presented to estimate sources' elevation angles. In the second step, the estimated elevation angles are applied to extract the direction cosines and then to estimate sources' azimuth angles. Compared with most of the previous algorithms, the proposed algorithm offers advantages as: (1) uses the pressure-particle-velocity field vector sensor smoothing, which enables to offer more accurate elevation angles' estimates for correlated sources, without losing of array aperture; (2) requires no spectral searching and direction cosine pairing-match procedures. Monte-Carlo simulations are presented to verify the proposed algorithm's effectiveness.