Exploration of Teisi Knoll by autonomous underwater vehicle "R-One Robot"

Abstract

This paper outlines the exploration of Teisi Knoll by the autonomous underwater vehicle the R-One Robot, as carried out October 19-22, 2000, and presents images taken by the sidescan SONAR fitted to the bottom of the vehicle. The R-One Robot was launched from the R/V Kaiyo, started diving near the support ship, followed pre-determined tracklines which were defined by waypoints, and finally came back to the destination where it was recovered by the support vessel. In order to minimize positioning error, which is determined by the inertial navigation system and Doppler SONAR, the robot ascended to the surface several times to ascertain its precise position using the global positioning system, the antenna of which is fitted on the vertical fin. Taking advantage of this positioning system, the robot followed the pre-determined tracklines with an error of less than 40 meters in 30 minutes of continuous diving. Disturbance to the robot is small enough compared to towed vehicles that its movement can be regarded as stable. This stability resulted in clear side scanning images of the knoll and the surrounding sea floor. The robot stopped at the center of the knoll, and descended vertically into the crater. When the vehicle was in the crater, anomalous manganese ion concentrations were detected by the in situ trace metal micro-analyzer GAMOS at the front of the robot.