No abstract

The project DESIBEL, funded by the European Union (MAST-2 programme), included development of the underwater vehicle demonstrator SIRENE. The free-swimming, acoustically remote operated vehicle is designed to place and recover deep-sea measuring stations on the sea-floor.An acoustic data link allows to monitor the vehicle state from the surface and to send guidance commands. The positioning system consists of an acoustic rangemeter working with transponder beacons and of sensors describing attitude and movement of the vehicle.The position estimator realizes two functionalities: first, it realizes selection of consistent sensor measurements; secondly it computes a position estimate from the validated information.The sensor system as well as the positioning algorithm are the subject ol rhis p a p . Results from various sea-tri ' ' y undertLLk n betv .en june and december 1997 ;ustrate the describcJ methods and allow to discuss future improvements.. .