Deep Long Life Passive Sonobuoy Sensor System

A passive long-life A-size sonobuoy vertical acoustic sensor array designed for the low frequency band from 5 to 500 Hz located near the bottom in the deep ocean will be developed. The array will be deployed for a period of up to two weeks and will take advantage of the Reliable Acoustic Path (RAP) conditions that occur when the sound velocity at depth exceeds the maximum sound velocity in the vicinity of the upper edge of the deep sound channel, as well as of the lower acoustic ambient that is found below this critical depth. The Phase I developed candidates, and performed modeling and simulation activities to evaluate prospective designs associated with the sensor types, array, telemetry, packaging, deployment and self-noise remediation within the overall architecture of an A-size sonobuoy. Analytic computer models of alternative designs were evaluated. While an array of omnidirectional hydrophones was identified as a prime candidate for the sonobuoy, a slightly shorter array with a directional sensor in the center was identified as a worthwhile candidate.Because they share many common elements, both the omni and directional arrays will be developed and tested in Phase II. Prototypes of the final design will be fabricated and tested.