A complete solution to underwater navigation in the presence of unknown currents based on range measurements from a single location

An underwater navigation algorithm is considered that enables an underwater vehicle to compute its trajectory and unknown currents by utilizing range measurements from a single known location. By assessing local observability about potential vehicle trajectories, we characterize those trajectories that cannot be asymptotically estimated. Analysis is also presented to clarify the relationship between finite time observability, a theme of this work, and existence of an observer with exponentially decaying observation dynamics. The navigation algorithm is illustrated using a hardware experiment.