Session: 05-04-01 CCUS and Underwater Development/ Utilization

Submission Number: 157519

Evaluation of Acoustic Positioning of Underwater Vehicle From Seabed Lander System in an Ocean Experiment 

In order to observe In Japan Agency for Marine-Earth Science and Technology (JAMSTEC), a seabed lander system have been developed for observation at the deepest parts of the ocean up to 11,000 meters depth.  In order to expand the observation area and function of the lander, a small underwater vehicle system, which is launched from the lander, is under development.  The vehicle is currently tethered to the lander with a electrical cable, and in the future it is planed that the vehicle will cruise without the tether cable as an autonomous underwater vehicle (AUV).  Then the vehicle is positioned by the lander and communicate with that acoustically.  The lander has an acoustic communication and positioning system, with which that lander communicates with its mother ship on sea surface and the vehicle.  At the same time the lander measures the relative position of transmitter, i.e. both the mother ship and the vehicle, with the synchronization signal of the acoustic communication packet using super short baseline (SSBL) method. 

In this study, an experimental evaluation result of the acoustic positioning of the vehicle from the seabed lander system is introduced.  The experiment was conducted in a sea area, the depth is about 100 meters.  The lander was places on the seabed and the vehicle was hung from a ship or cruised around the lander.  The lander was equipped with a horizontally planer receiver array consists of five receivers in order to process SSBL positioning.  The acoustic system has a chip scale atomic clock (CSAC) and synchronization of the lander and the vehicle was precise.  Then the measurement of the distance was achieved with one-way propagation time of the acoustic signal.  Evaluation was conducted with receiver arrays of two sizes.  The positioning was performed within 1 meter order.  On the other hand, in the positional relationship between the lander and the vehicle, the distance was horizontal direction near the seabed of sharrow water.  Then there were outliers of the positioning result to some degrees.

Presenting Author: Yoshitaka Watanabe JAMSTEC

Presenting Author Biography: Yoshitaka Watanabe received the B.S. and M.S. degrees in fluid dynamics from Keio University, Japan, in 1999 and 2001, respectively, and received the Ph.D. degree in Tokyo University of Marine Science and Technology in 2009.
In 2001, he joined Japan Agency for Marine-earth Science and Technology. He belongs research group on underwater acoustic technology. His current research interests include underwater acoustic positioning and communication, and navigation of underwater vehicles.