Range-only positioning of a deep-diving Autonomous Underwater Vehicle from a surface ship

This paper describes a method for the precise postprocessed positioning of a deep-diving autonomous underwater vehicle (AUV) using only a set of acoustic ranges from a surface ship while the AUV executes a closed path under the ship. This approach avoids the use of either a precisely calibrated (and consequently expensive) ultrashort baseline (USBL), or a long baseline (LBL) system (which is expensive in ship time to deploy). Results of Monte Carlo simulation and field results from the first trials of the Autosub6000 AUV are presented to support the hypothesis that an AUV at 6000-m depth can be positioned to an accuracy commensurate with global positioning system (GPS) quality or better, within a period of 1 h.