Experimental testing of detection, localization, and call density of synthetic sounds using Navy surplus sonobuoys.

A series of synthesized sounds were played back from multiple locations around and within a grid of four DIFAR sonobuoys. Four type 53F DIFAR sonobuoys with attached SPOT GPS devices were deployed in a square with ~1nmi (2km) between each sonobuoy. Sound sources include periodic deployment of weighted light bulbs (producing an impulsive sound when the bulb implodes at depth) and synthetic tonal sounds broadcast through an underwater speaker. A time-synchronized multi-channel recording was made of the sounds received on the four sonobuoys. These experimental data have been used for multiple studies including testing methods to estimate sonobuoy drift, testing novel methods for detection and localization of sonobuoy signals, and testing methods for Acoustic Spatial Capture-Recapture (ASCR) methods for estimating call density. We encourage use of these methods for additional research and development.