Underwater Target Localization Using Opportunistic Ship Noise Recorded on a Compact Hydrophone Array

Mojgan Mirzaei Hotkani,Seyed Alireza Seyedin,Ehsan Malekshahi,Bruce Martin,Jean-Francois Bousquet

doi:10.3390/acoustics3040039

Mojgan Mirzaei Hotkani, Seyed Alireza Seyedin + Show 3 more

Open Access

https://doi.org/10.3390/acoustics3040039

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Abstract

In this research, a new application using broadband ship noise as a source-of-opportunity to estimate the scattering field from the underwater targets is reported. For this purpose, a field trial was conducted in collaboration with JASCO Applied Sciences at Duncan’s Cove, Canada in September 2020. A hydrophone array was deployed in the outbound shipping lane at a depth of approximately 71 m to collect broadband noise data from different ship types and effectively localize the underwater targets. In this experiment, a target was installed at a distance (93 m) from the hydrophone array at a depth of 25 m. In this study, a matched field processing (MFP) algorithm is utilized for localization. Different propagation models are presented using Green’s function to generate the replica signal; this includes normal modes in a shallow water waveguide, the Lloyd-mirror pattern for deep water, as well as the image model. We use the MFP algorithm with different types of underwater environment models and a proposed estimator to find the best match between the received signal and the replica signal. Finally, by applying the scatter function on the proposed multi-channel cross correlation coefficient time-frequency localization algorithm, the location of target is detected.

Highlights

Nowadays, ocean acoustic scientists pay significant attention towards to the use of passive approaches instead of active techniques for ocean sensing due to the environmental regulations prohibiting the transmission of invasive noise source; passive sensing reduces the cost and energy consumption for remote nodes
A new technique was presented based on the use of ambient noise as a type of secure signaling
The signal generated by the rotation of the propellers of moving ships can act as a sonar signal source and as an opportunistic noise source that detects the position of the target by receiving its scattering from the surface of objects using the hydrophone arrays

Summary

Introduction

Ocean acoustic scientists pay significant attention towards to the use of passive approaches instead of active techniques for ocean sensing due to the environmental regulations prohibiting the transmission of invasive noise source; passive sensing reduces the cost and energy consumption for remote nodes. Opportunistic sources refer to acoustic energy existing in a maritime medium that has not been generated for the clear aim of ocean measurement. Wave noise and noise generated by sea ice and ships are known examples of acoustic sources of opportunity [1]. Ship noise can be considered as an active acoustic source for monitoring the ocean, despite its undesirable effects on the life of marine mammals. The cavitation introduces a rapid change of pressure in a liquid, which leads to small vaporfilled cavity formations in places where the pressure is relatively low. At higher pressures, these cavities, called “bubbles” or “voids”, collapse and can generate a high intensity shock wave. Ships are powerful and underutilized acoustic sources of opportunity that can be used to obtain information about the marine environment and target localization [8]

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