Fully Autonomous Observation of Breakwaters by an Auv at Kamaishi Bay

This paper proposes a robust navigation method for Autonomous Underwater Vehicles (AUVs) operating around structures such as harbors and breakwaters. This method consists of a state estimator and a motion controller, enabling localization in the configuration map as well as following pre-given waypoints without any external help. The state estimator is based on a “particle filter” where the vehicle’s state, horizontal position and heading, is stochastically updated in real time using multi-sensor data. This method was actually implemented to a testbed AUV “Tri-Dog 1” and a series of sea trials were carried out around breakwater caissons at the mouth of Kamaishi bay in Japan. This is the first time an AUV has succeeded in fully autonomous observation around breakwater caissons. Mosaics of the foot protection blocks, rock mound and caisson’s surface are made from the observed images based on the estimated state of the AUV, to verify the performance of the method.