Comparison of Passive Acoustic Monitoring sensors for Direction of Arrival estimation of underwater acoustic sources

This paper compares experimental performance obtained using Passive Acoustic Monitoring (PAM) sensors to estimate the Direction of Arrival (DoA) of an acoustic signal emitted by an underwater source. The PAM sensors analysed are the Wilcoxon VS-301 and VS-209 Vector Sensors (VSs), and the hydrophone array Geo-Sense Mini-streamer. The data used to make the comparison was obtained from experimental missions in which the PAM sensors were installed on the X300 Autonomous Underwater Vehicle (AUV). The experimental tests were run in coastal busy environments and with different geometries to analyse the robustness against noise, configurations and signal processing algorithms. Results show how VSs and classic hydrophone arrays have different strengths and capabilities. Within the specific experimental environments of our tests, these initial results show that the hydrophone array might achieve low average errors (less than 3.5^◦) and high precision (standard deviation less than 10^◦) but might be more susceptible to geometry variations. The VSs obtained lower accuracy, with an average error below 20^◦ and lower precision with a standard deviation between 5° and 80°. They were also more sensitive to thrusters and vehicle motion. However, they are much more compact and represent a logistically simple solution that can be very appealing for deployments on AUVs. This work is part of the Distributed Autonomous Mobile Passive Sonar system (DAMPS) research project, which aims at developing a multi-robot system for the position tracking of noise sources in underwater environments.