The AQS-20A is an airborne SONAR mine countermeasure detection system, developed by Raytheon. The system is utilized by the MH-60S and MH-53E helicopters and as part of the mission package for the Littoral Combat Ships (LCS) and some United States Navy Destroyers of the Arleigh Burke class. However, only one destroyer has been outfitted with the specific mission package as of April 2009. The AN/AQS-20 mine hunting sonar systems will be employed for deeper mine threats. The "Q-20", as it is commonly called, is an underwater towed body containing a high resolution, side-looking, multibeam sonar system used for minehunting along the ocean bottom. This rapidly deployable system provides real-time sonar images to operators in the aircraft to locate, classify, mark and record mine-like objects and underwater terrain features. The AQS-20 has an active, stabilized underwater vehicle, equipped with advanced multiple-beam side-looking sonar. The helicopter tows the underwater body by a small-diameter electromechanical cable while on board the helicopter, an operator can view the underwater image and identify objects on a video monitor while recording the data on S-VHS digital tapes for post mission analysis. Operators actually fly the device underwater, controlling the depth of the device the same way that an airplane controls its altitude. Once located, the exact coordinates of mine-like objects can be used by Explosive Ordnance Disposal (EOD) personnel to reacquire and neutralize the mine.
Per the Joint Electronics Type Designation System (JETDS), the nomenclature AN/AQS-20A is derived this way:
||Nomenclature has been derived from the JETDS
||Installed on a piloted aircraft
||Used for Detecting, Range and Bearing, Search
||Unique designator for this particular unit
||First variant on the base unit