Whale 3D monitoring using astrophysic NEMO ONDE two meters wide platform with state optimal filtering by Rao-Blackwell Monte Carlo data association

This paper proposes an algorithm for whale monitoring by passive acoustic using four short-spaced hydrophones. It is successfully tested on the NEutrino Mediterranean Observatory – Ocean Noise Detection Experiment (NEMO ONDE) underwater acoustic platform. In past years, interest in marine mammals has increased, leading to the development of passive acoustic methods of localization which permits to study whales’ behavior in deep water (several hundreds of meters) without interfering with the animals. In this paper, we propose a robust Angle of Arrival (AoA) tracking algorithm, which provides an estimation of elevation and azimuth angles in spite of the short distance between hydrophones, which does not allow direct 3D localization. Moreover we show that, in some cases, the time-delay between direct signal and its reflection on the sea surface allows the range estimation, and thus the exact localization of the whale. The classic AoA estimation is performed with a non-linear regression, and it is compared with a more sophisticated algorithm, the Rao-Blackwell Monte Carlo Data Association. We demonstrate that the second method is very robust to the presence of clutter. According to the Pavi 2009 workshop challenge, our algorithm is the only one performing relevant tracks of whale.