Unmanned localization of sperm whales in realistic scenarios

In this paper an unmanned sperm whale localization technique is presented. It focuses on the localization of sperm whales using a two-hydrophone array passive localization system. It is based on the beamforming technique and on the time delay between the direct and surface reflected wavefronts. The proposed method is based on that presented by E. K. Skarsoulis and it aims to develop a low computational complexity signal processing system, which can operate autonomously in remote buoys with power and computational limitations. This study consists on the analysis of the improvements provided by using beamforming theory on the method proposed in. The equipment used mainly composed of two hydrophone arrays deployed near the surface. It was found that the accuracy of this methodology depends on the array´s location and can be improved by increasing the depth and the separation between the arrays and/or decreasing the angle formed by the line which crosses through the arrays with respect to the horizontal plane. The performance of the proposed method is evaluated through simulations using a real sperm whale signal in deep water, in presence of low and high SNR. The enhancements are proven in the extraction of the direct and surface-reflection arrival times as well as the arrival angle for each path under realistic conditions.