Localizing underwater acoustic pingers using a streamlined method with an autonomous unmanned vehicle

Abstract

Locating assets underwater is an important role of AUVs and Gliders. One instance is the recovery of black boxes from downed aircraft. All aircraft have an acoustic beacon attached to their flight data recorder that activates upon impact with water. Currently, to find the recorder a ship will search a large area towing a hydrophone while human operators carefully listen for the beacon’s pings. This is very costly! After searching the entire area, an estimate of the beacon’s location is made based on the loudness and spatial distribution of detections. Is this reliable? Is there enough time before the beacon’s battery dies? This talk presents a streamlined approach for locating pingers on the seabed. Here, an AUV replaces the ship, two hydrophones replace the towfish, and a small processor containing an automatic ping detector and localization algorithms replace human operators. The method exploits the AUV backseat driver in order to form synthetic hydrophone arrays and to diminish the search area after a ping is detected. Not only does this streamline the AUV’s route but also pinpoints the location of the blackbox from far away. The method will be introduced and results of field trials shown.