Numerical Studies of Object Localisation Using Ocean Acoustic Tomography

Ocean acoustic tomography (OAT) is a technique used to study ocean properties by analysing sound wave propagation. In this study, OAT is used to detect and localise underwater objects by analysing variations in acoustic wave propagation caused by their presence. This paper explores the application of acoustic tomography for underwater object localisation through numerical modeling. Using COMSOL Multiphysics and the finite element method, a two-dimensional harbour model is developed, incorporating an acoustic monopole as a sound source, forty hydrophones, and a rectangular object. The study analyses the impact of object positioning on acoustic pressure distribution in both time and frequency domains. The results indicate that hydrophones located close to or nearby an object’s position show visible anomalies, captured both in time signals and frequency-amplitude spectra. Similar patterns were observed for certain positions of hydrophones, whereas receivers located farther from the object did not capture any significant differences.