PARADIGM: a buoy-based system for AUV navigation and tracking

A large variety of Autonomous Underwater Vehicles (AUVs) are currently under development or in production. In order for an AUV to be useful, its self-navigation capabilities must support the mission requirements. Often, underwater acoustic navigation techniques must be utilized in order to meet the navigational accuracy requirements. In addition to vehicle self-navigation, most AUV operators also require a method of tracking the vehicle while it is underway, so that its progress may be monitored, and also so that it may be located easily upon surfacing, or in the event of a vehicle failure. The Woods Hole Oceanographic Institution (WHOI) has developed a buoy-based system that simultaneously provides for both vehicle self-navigation and external tracking. This system has been used extensively by WHOI to support the REMUS AUV operations, and has also been used by the Naval Oceanographic Office to support sea-trials of the LAZARUS vehicle system. Long Baseline Acoustic Navigation is often the preferred subsea navigation method. It is generally accomplished by deploying two or more acoustic transponders, moored to the seafloor, near the desired area of operations. The vehicle then interrogates the transponders, determines its range to each, and finds its position using triangulation techniques. WHOI has developed a radio-controlled buoy, which can serve as a navigation transponder for the vehicle, and can also be commanded via the radio link to interrogate the AUV and report the measured travel time back to the operator. This paper describes the PARADIGM (Portable Acoustic RADio Geo-referenced Monitoring) system architecture, and presents data describing results achieved