Estimation of wave glider dynamics for precise positioning

The wave glider is a new autonomous surface platform with unique capabilities for persistent observation in a variety of marine environments. The applications of this novel technology continue to expand; some of the potential oceano-graphic applications will require precise positioning and navigation beyond the platforms current capabilities. In this article we discuss the potential for precise localization of a wave glider based on a augmenting the onboard instrumentation (adding a high quality global positioning receiver and inertial measure unit) and implementing an estimation algorithm (an extended Kalman filter using a two-body dynamic model). To understand the capabilities and limitations of the wave glider´s novel propulsion mechanism, consisting of a surface float and submerged glider to harvest wave energy for forward motion, we propose a simplified dynamic model appropriate for real-time implementation. The physical parameters of this model are identified using experimental measurements collected from a wave glider operating in a coastal environment. Finally, we present the results of a proof-of-concept field experiment where the wave glider at the surface was used to precisely position a instrument moored to the seafloor to evaluate the performance of the wave glider for the type of mission that requires precise navigation.