Research on the broadband source localization of a vector hydrophone vertical line array in the deep sea

This paper develops an approach that estimates the range and depth of a broadband source by adopting the vector hydrophone vertical array (VHVA) in the deep ocean. The sound field in the direct wave zone is mainly composed of direct (D) and once-sea-surface-reflected (S1B0) waves. The arrival angles and time delays of the two waves are consistent. The combined beamforming technology is applied to the VHVA to accurately obtain the elevation angles and further enhance the received signal-to-noise ratio (SNR). The source ranges are then estimated according to the simple geometric relationship. The source depth estimation model is established based on the Lloyd-mirror principle, which relates the interference properties of D and S1B0 to the oscillation period of the combined signals of VHVA. The feasibility and availability of this method are validated by both simulations and sea trials in the South China Sea. The experimental results indicate the range estimation error of the moving vessel is less than 10% and the surface or submerged targets can be effectively determined. Our proposed algorithm has the strong benefits of simple principle, low computational complexity and small error. These properties indicate this algorithm can be used in target detection in the deep sea.