Ship detection and tracking from single ocean-bottom seismic and hydroacoustic stations

Abstract

We report in this study how ocean-bottom seismometers (OBS) can be used as passive sonars to automatically detect, localize, and track moving acoustic sources at the ocean surface. We developed single-station methods based on direction of arrival and on multi-path interference measurements capable of handling continuous erratic signals emitted by ships. Based on a Bayesian mathematical framework, we developed an azimuthal detector and a radial detector and combined them into a fully automatic tracker. We tested the developed algorithm on seismic and hydroacoustic data recorded in the Indian Ocean by an OBS deployed at 4300 m depth, 200 km west of La Réunion Island. We quantified the performances using archives of commercial-vessel trajectories in the area provided by the Automatic Identification System. Detectors demonstrate capabilities in the detection range up to 100 km from the OBS with azimuthal accuracies of a few degrees and with distance accuracies of a few hundred of meters. We expect the method to be easily transposed to any other kind of sources (such as marine mammals).

Study of the strength characteristics of particle velocity at the seabed interface

“…Previous studies have focused on the effect of seabed acoustic parameters on the acoustic pressure signal, or only on the acoustic vector signal distributed in the seawater medium [1], but fewer studies have been conducted on the particle velocity signal received at the seabed interface. In recent years, due to the low attenuation characteristics of low-frequency signals and the superiority of receiving low-frequency signals using the Ocean Bottom Seismometer (OBS), the acquisition of low-frequency vector signals at the seabed interface using the OBS has provided a new research idea for long-range detection [2,3]. Therefore, in order to provide a better propagation theoretical basis for the substrate receiver research work, the acoustic field characteristics of the seabed interface have received considerable attention from scholars at home and abroad.…”

Matched Stochastic Resonance Enhanced Underwater Passive Sonar Detection under Non-Gaussian Impulsive Background Noise

“…Theoretical and experimental results have proven that there are abundant low-frequency periodic components that are related to the engine and propeller. Therefore, remote passive sonar detection with very-low-frequency ( f ≤ 100 Hz) signatures has attracts lots of attention [8][9][10][11].…”

Forward simulation of unfavorable geological bodies and analysis of waveform characteristics based on time domain finite difference method

“…type, direct current method type, and other forms. At present, the commonly used seismic advance detection in practical engineering mainly includes tunnel seismic prediction (TSP) developed in Switzerland [8][9] , tunnel geological prediction (TGP) developed in China [10] , and tunnel seismic tomography prediction (TST) [11] , true reflection tomography prediction (TRT) developed in the United States [12] , land sonar method [13] , etc. The electromagnetic category mainly includes ground penetrating radar prediction (GPR) [14][15] and transient electromagnetic method prediction (TEM) [16][17] .…”