Temporal combination of positioning modes for AUV navigation in perturbed environments

We present a positioning system for AUVs that relies on the possibility of using its acoustical subsystem in two distinct modes: a high accuracy active mode, which is energy consuming, and a degraded passive mode, which requires no emission from the vehicle. This enables efficient use of the available on-board energy, by providing reliable estimates of external forces acting upon the vehicle (sea currents), and allowing a minimum amount of active interrogation of the acoustic transponders. The paper presents the entire architecture of the positioning system and simulation results that demonstrate the importance of careful distribution, along the mission, of the active navigation mode