Comparing noise vessel azimuth tracking with a planar hydrophone array and a single vector sensor

C. Soares(1), F. Zabel(1), P. Santos(2)) and A. Silva(2)
(1) Marsensing Lda, Faro, Portugal
(2) LARSyS, University of Algarve, 8005-139 Faro, Portugal

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Ref.: INCREASE'2023, July 2023

Vector sensors are appealing for monitoring underwater noise due to its inherent directivity. While acoustic pressure sensors are ambiguous in all directions, vector sensors permit the aquisition of directional information through the measurement of particle velocity, which enables the possibility of azimuth tracking of underwater noise sources. Underwater acoustic systems based on vector sensors can play an interesting role in Marine Protected Areas where integrated marine observatories are needed to assess the evolution of the environmental state. The MARREAL marine observatory is a marine observatory equipped with a number of sensors and subsystems, including an acoustic acquisition system made of four hydrophones and a vector sensor. The observatory was deployed in September 2022 in Sagres, Portugal, near the Baleeira Port which is accessed by fisher boats and recreational boats. This paper shows preliminary results on azimuth estimation of boats passing in the deployment area, obtained independently with a 4-hydrophone planar array and a vector sensor. The results indicate that a single vector sensor can provide fair results on azimuth tracking of boats passing in the area. At high signal-to-noise ratio (SNR) the vector sensor is able to yield results similar to those obtained with the planar array. When the SNR is low the planar array outperforms the vector sensor with the actual processing methods used.