The uncertainty behavior of an enhanced three-dimensional (3D) localization scheme for pulsed sources based on relative travel times at a large-aperture three-hydrophone array is studied. extension two-hydrophone approach time differences between direct and surface-reflected arrivals, with significant advantages, but also drawbacks, such as left-right ambiguity, high range/depth uncertainties b...

Estimates of the noise source spectra of ships based on long term measurements in the Baltic sea are presented. The measurement data were obtained by a hydrophone deployed near a major shipping lane south of the island Öland. Data from over 2,000 close-by passages were recorded during a 3 month period from October to December 2014. For each passage, ship-to-hydrophone transmission loss (TL) spe...

Two filter based approaches for deghosting of Ocean Bottom Cable data are presented. One of them is phase shifting of geophone followed by least square matching of cross ghosted geophone and hydrophone data.In the second approach,phase shifting of geophone is followed by direct matching of geophone’s amplitude spectrum with that of the hydrophone within the seismic bandwidth.Results obtained fr...

Acoustic communication experiments were carried out during multistatic submarine searches in a littoral area. The purpose of the communication is to send information from the active transmitter to bistatic receivers. After transmission with a low-frequency source, phase-shift keyed signals were recorded on various hydrophone arrays towed by remote platforms. Message recovery is complicated by a...

Clinical ultrasound (US) imaging and therapy require a precise knowledge of the intensity distribution of the acoustic field. Although piezoelectric hydrophones are most common, these devices are limited in terms of, for example, type of materials, cost, and performance at high frequency and pressure. As an alternative to conventional acoustic detectors, we describe acoustoelectric hydrophones,...

According to the auditory principle of fish’s lateral line organ, a novel microelectromechanical systems (MEMS) bionic vector hydrophone used for obtaining vector information of underwater sound field is introduced in this paper. It is desirable that the application of MEMS-based piezoresistive effect and bionics structure may improve the low-frequency sensitivity of the vector hydrophone as we...

Despite their simple geometry, uniform linear arrays suffer from port-starboard ambiguity. Triplet arrays, where a set of three hydrophones is used inplace of a single omni-directional hydrophone, is one possible solution to the problem. An alternative is vector sensor arrays inwhich each hydrophone is replaced with acoustic vector sensor that measures both the acoustic pressure and particle ve...

This paper develops an efficient three-dimensional localization method for transient acoustic sources, with uncertainty estimation, based on time differences between direct and surface-reflected arrivals at two hydrophones. The localization method accounts for refraction caused by a depth-dependent sound-speed profile using a ray-theoretic approach for calculating eigenray travel times and part...