Underwater Positioning System Based on Drifting Buoys and Acoustic Modems

GNSS (Global Navigation Satellite System) positioning is not available underwater due to the very short range of electromagnetic waves in sea water medium. In this article a LBL (Long Base Line) acoustic repeater system presented. The hyperbolic, i.e., based on time differences and it does need accurate atomic clocks synchronize repeaters. architecture calculations that demonstrate feasibility solution are uses four buoys sequentially transmit their position instant transmission, for which they equipped with receivers modems. can be fixed or even drifting, but inexpensive devices, pose no hazard navigation easily quickly deployed specific mission. multilateration algorithm used receiver To simplify algorithm, depth receiver, measured by sensor, used. Results presented error an vehicle its displacement during transmission frame buoys.