OVERVIEW: Directional Sonobuoys are expendable acoustic sensors deployed from aircraft or ships to detect and localize underwater sound sources, primarily submarines, by passively listening to emitted noises.

GENERAL DESCRIPTION: These sonobuoys use hydrophones arranged to determine the direction of underwater acoustic signals without emitting any active pulses, enhancing stealth and tactical awareness. They are widely used in anti-submarine warfare (ASW) to provide bearings to contacts, assisting in tracking and targeting. Deployed individually or in patterns, they transmit acoustic data via radio to ASW platforms for analysis and action.

ROLE SUMMARY:
Category: Passive Sonobuoy
Primary Use: Underwater acoustic detection and bearing estimation
Function: Passive listening and direction finding of submarine noise
Platform: Maritime patrol aircraft, ASW helicopters, surface ships
Integration: Linked to ASW command and control and sonar systems

See Specific information under [Sensors/EW] and [Properties] sections.

SOURCE:
Jane’s Underwater Warfare Systems
Naval Technology Publications