From Citizendium, the Citizens' Compendium
- Acoustic warfare : Add brief definition or description
- Geophysical MASINT : A branch of measurement and signature intelligence that involves phenomena transmitted through the earth (ground, water, atmosphere) and manmade structures including emitted or reflected sounds, pressure waves, vibrations, and magnetic field or ionosphere disturbances.
- Measurement and signature intelligence : A variety of intelligence gathering disciplines complementary to the technical "mainstream" of imagery intelligence and signals intelligence. (MASINT)
- Hydrophone : Add brief definition or description
- Sonobuoy : Air-dropped, expendable sensors for anti-submarine warfare
- SURTASS : Add brief definition or description
- Target motion analysis : Add brief definition or description
- Towed array : Add brief definition or description
- Transducer : Device, usually electrical, electronic, electro-mechanical, electromagnetic, photonic, or photovoltaic, that converts one type of energy or physical attribute to another for various purposes.