A sonobuoy is a device used to detect and identify objects moving in the water. Typically, a sonobuoy is used to detect submarines by either listening for the sounds produced by propellers and machinery (passive detection) or by bouncing a sonar “ping” off the surface of the submarine (active detection). Multi-static operations utilize separate active source and passive receiver sonobuoys. Multi-static techniques are also used for submarine detection and localization. Specialized sonobuoys can also detect electric fields and magnetic anomalies, as well as measuring environmental parameters like water temperature versus depth, air temperature, barometric pressure, and wave height.

Sonobuoys are generally dropped from aircraft that are equipped with a means to launch them and electronic equipment to receive and process data sent by the sonobuoy. Sonobuoys may also be deployed from virtually any sea platform.

Sonobuoys are classified by size (A, B, C, etc.) and type (active, passive or measurement). All U.S.-manufactured sonobuoys, except the MK-84, are A-size (approx. 4 7/8 in. X 36 in.). Some countries have moved to half-size, or A/2, as a preferred configuration.

During the Cold War, passive detection in deep water was the strategy of choice to covertly track nuclear submarines around the world. Since former Soviet Union and NATO relations have changed, detection needs have fluctuated. An increase in the number of diesel electric submarines under the flag of third world nations has led to an increase in the interest in active sonobuoys and shallow water detection techniques.

Sonobuoy Tech Systems offers a full line of sonobuoys and technical support to address modern Anti-Submarine Warfare (ASW) needs.

Sonobuoys with different characteristics other than those described can be designed and built to customer requirements, following a careful analysis of needs. Sonobuoy TechSystems has designed and manufactured many sonobuoy variations over the years and continues to make high-performance, high-reliability sonobuoys.