AUV Tri-TON — A hover-capable platform for 3D visualization of complicated surfaces

AUV Tri-TON is a hovering type autonomous underwater vehicle developed by the University of Tokyo, launched in 2011. The vehicle was constructed as a testbed under the governmental project to develop instruments to estimate ore reserves in underwater hydrothermal deposits. The vehicle's mission is to obtain dense, large-area 3D image of hydrothermal vent fields, in collaboration with a seafloor station. The information will be also used for environmental assessments, mine planning, and educational activities. Although the vehicle is not equipped with an inertial navigation system (INS), the vehicle can estimate its position in real-time with a precision enough for rough photo-mosaicking, owing to the mutual acoustic positioning with the station. The vehicle has two suites of imaging instruments looking forward and downward directions in order to image whole surface of bumpy hydrothermal vent fields. The vehicle has been tested through a series of experiments at tanks and real fields. In April 2012 the vehicle was deployed to the hydrothermal vent field of Kagoshima Bay in Japan and succeeded in observing seafloor with the area of around 200 square meters.