Reducing the noise introduced by the engine of a moving autonomous vehicle for recording underwater sounds

摘要

In this work, a hydrophone has been integrated in a moving autonomous underwater vehicle (AUV) in order to have an autonomous controlled system capable of recording underwater audio. The performance of the system, in terms of best recording of the audio, has been analyzed by placing the hydrophone in two different positions: the front of the AUV and its lower part. From this analysis, it has been determined that the best position for the hydrophone (i.e., the one that receives the lowest engine noise) is the former. In addition, a signal processing based on an order analysis has been performed for the purpose of filtering the noise introduced by the engine of the AUV. This technique achieves the filtering of most of this noise without removing contributions from other sources of interest whose frequency spectrum overlaps with the noise of the engine. This is a fundamental characteristic of the new system because it allows for cleaner underwater recordings. The aim is to increase the capabilities for detection of sources emitting in the range of the AUV acoustic contribution by reducing the same and not so much by completely removing it. (C) 2019 Elsevier Ltd. All rights reserved.