Using Slocum gliders for coordinated spatial sampling

Buoyancy driven Autonomous Underwater Vehicles (AUVs), such as the Slocum glider, allow for a prolonged presence to study the oceans. They can operate for weeks or even months recording oceanographic data for a fraction of the cost of research vessels. However, the vehicles are limited to the number of sensors that can be carried onboard. Alternatively, a group of AUVs performing formation flight, where AUVs maintain particular positions relative to each other, could be used to observe ocean conditions and phenomena at a high spatiotemporal resolution carrying a variety of sensors. The vehicles can conceptually act as a single science instrument that can be easier and less expensive to deploy than higher cost, large AUVs. In this paper we propose and evaluate, using simulations, an effective coordination strategy for formation flight which monitors the formation quality using underwater communication. If an AUV drifts out of formation, all vehicles are instructed through underwater communication to resurface in order to reestablish the formation. Overall, this strategy is able to keep a formation of gliders longer than the traditional approach and can gather significantly more data samples, which corresponds to an overall decrease in the per sample energy cost.