Diver navigation and tracking system

This paper describes an intelligent underwater acoustic system that allows the positions of several divers to be tracked in three-dimensional space and to telemeter each diver´s co-ordinates to a remote receiver at the surface. The positions of the divers are fixed using three randomly deployed seabed transponders that may be described as `intelligent´. The transponders fix their own relative positions and the position of the surface receiver, usually a vessel, by an exchange of coded acoustic pulses. These positions can be related to a differential GPS system at the surface if absolute co-ordinates are required. The divers each know their own position from a wrist-worn computer with a backlit graphical/numerical display. As well as the current position, the display can show the track from the beginning of the dive, the location of the surface vessel and the instantaneous position of the other divers. Also, a transponder can be attached to remotely operated vehicle (ROV) or autonomous underwater vehicle (AUV) to allow the position and data of the vehicle to be tracked by the surface vessel and by any divers in the vicinity