Coherence extrapolation for underwater ambient noise

Coherence extrapolation for underwater ambient noise.

This paper considers extrapolation of the vertical coherence of surface-generated oceanic ambient noise to simulate measurements made on a longer sensor array. The extrapolation method consists of projecting the noise coherence measured with a limited aperture array into the domain spanned by prolate spheroidal wave functions, which are an orthogonal basis defined by array parameters and the no...

Underwater Ambient Noise

Effect of Underwater Ambient Noise on Quadraphase Phase-shift Keying Acoustic Sensor Network Links in Extremely Low Frequency Band

This study evaluates the impact of underwater ambient noise using seven real noise samples; Dolphin, Rain, Ferry, Sonar, Bubbles, Lightning, and Outboard Motor in three frequency ranges in extremely low frequency (ELF) band. The ELF band is the most significant bandwidth for underwater long-range communication. ELF band which is extended from 3 to 3000 Hz clearly, faces bandwidth limitation. Me...

13: Exploiting the Spatio-Temporal Coherence of Ocean Ambient Noise for Passive Tomography

Coherent processing of ambient noise, based on these computed noise cross-correlation between receivers, has been suggested as a potential means for developing passive methods for ocean acoustic tomography or thermometry [Roux et al., 2004]. However, this technique can require long recording times to extract stable coherent arrivals from ocean noise correlations [Sabra et al., 2005a; Godin, 201...

Exploiting the Spatio-Temporal Coherence of Ocean Ambient Noise for Passive Tomography

Extracting the coherent component of the ambient noise field propagating between a pair of passive receivers provides a means for passive acoustic sensing of the ocean environment. For instance, the arrival-times structure of the ambient noise cross-correlation time-function between a pair of receivers can yield an estimate of the arrival structure (or wavefronts) of the actual time-domain Gree...