Autonomous homing and docking for AUVs using Range-Only Localization and Light Beacons

This paper proposes a method for homing and docking an Autonomous Underwater Vehicle (AUV) to a subsea Docking station (DS) by combining acoustic and optical sensing. The AUV is assumed to be within acoustic ranging distance to the DS, whose location is otherwise unknown a priori . The homing and docking procedure comprises two stages. In the first stage, a Sum of Gaussian (SoG) filter is used to estimate the DS location while the AUV is guided along an observable trajectory. Once the DS position becomes known, the vehicle performs a homing maneuver to bring it within visual reach of the DS. In the second stage, a light beacon navigation system is used to estimate the DS pose with respect to the AUV. Visual information is used to update to a Simultaneous Localization And Mapping (SLAM) filter providing an AUV-pose estimate with the accuracy required for the docking maneuver. The feasibility and performance of the method is evaluated through Hardware-in-the-loop (HIL) simulation. The novelty and impact of the proposed approach lies in the complementarity of the two sensing modalities, which have not been yet demonstrated for AUV docking.