Root-MUSIC-based azimuth-elevation angle-of-arrival estimation with uniformly spaced but arbitrarily oriented velocity hydrophones

This novel underwater acoustic azimuth-elevation source localization scheme realizes the eigenstructure-based polynomial rooting procedure for an L-shaped uniformly spaced array of diversely oriented and possibly spatially co-located velocity hydrophones and an optional pressure hydrophone. A velocity hydrophone measures a Cartesian component of the acoustic particle velocity vector of the incident wavefield. At each uniformly spaced array grid, one or more co-located and diversely oriented velocity hydrophones and/or a pressure hydrophone are placed, with the number and orientations of velocity hydrophones possibly varying from grid position to grid position in some known prearranged manner. The diverse orientation of the velocity hydrophones, however, disrupts the Vandermonde array manifold structure in each of the two uniform-linear-array legs of the L-shaped array. Nonetheless, ingenuous mathematical manipulations proposed in this paper restore the disrupted Vandermonde algebraic structure, thereby permitting once again the use of polynomial rooting to estimate the directions of arrival. A proposed pairing procedure matches each source’s x-axis direction cosine estimate with its corresponding y-axis direction cosine estimate. Simulation results verify the efficacy of the proposed scheme.