Abstrait

Underwater Positioning ROV Using Multiple Transducers

P. Bini Palas,, Abilash Jose

This paper introduces the implementation of positioning ROV in underwater navigation solution using multiple transducer technique, which is based on USBL, DGPS, DVL and AHRS measurements. To realize the accurate key element of sub-sea position and frequent update rate of underwater navigation solution, three approaches are chosen. The first one is the underwater positioning system that uses a vessel mounted transceiver to detect the range and bearing to a target using acoustic signals. The second one is Doppler Velocity Log (DVL) that has been used to provide navigation information for ships, Remotely Operated Vehicles (ROVs), Human Occupied Vehicles (HOVs) and Autonomous Underwater Vehicles (AUVs). By using multiple transducers to measure velocity (either bottom tracking or water-column tracking), these observations can be integrated to generate displacements. These relative displacements, when oriented to realworld coordinate systems through heading, pitch and roll sensors can generate absolute displacements relative to geographic coordinate systems. The third one is an Attitude and Heading Reference system (AHRS) that consists of sensors on three axes that provide heading, attitude and yaw information for ROV. They are designed to replace traditional mechanical gyroscopic ROV instruments and provide superior reliability and accuracy, where the global position can be acquired from differential global position to provide improved location accuracy (USBL or DGPS) measurements, considering positioning state machine. Positioning at sea with different approaches can be done by verifying the developed algorithm using the obtained experimental data.