Field results from point to point real-time underwater acoustic tracking using a simple mathematical filter

MBARI has developed and field tested a simple real time single beacon acoustic underwater asset tracking algorithm using range and bearing data only. A Benthos USBL DAT mounted in a Liquid Robotics Wave Glider surface vehicle successfully tracked an underwater drifting Coastal Profiling Float and a moving Long Range Autonomous Underwater Vehicle, both of which were outfitted with Benthos acoustic modems, for up to four days. The algorithm uses an error function weighted moving average to filter range data combined with simultaneous bearing data to provide the Wave Glider with updated underwater position estimates. Successful field trials were conducted off Monterey, CA and Hawaii with results presented in this paper. The algorithm operates in real time and requires very low computational overhead.