Sonobuoys record and transmit underwater sounds using a transducer and a radio transmitter. Passive, active, and special-purpose sonobuoys are the three categories of sonobuoys. A hydrophone is used in passive Sonobuoys to listen for sound energy from a target. Active sonobuoys send an acoustic signal using a transducer and then listen for the return echo from an item. Special purpose buoys give extra environmental data, such as water temperature and wave height. These devices can be dropped into the ocean from heights as high as 30,000 feet.
The Directional Frequency Analysis and Recording (DIFAR) sonobuoy is a passive acoustic sonobuoy that the Navy uses to locate submarines beneath the surface. One or more vector sensors are included in DIFAR buoys, which provide the direction to the source of an auditory signal. Non-directional hydrophones are usually included as well Read more
