Single Beacon Acoustic Navigation for an AUV in the presence of unknown ocean currents

This paper addresses the problem of underwater navigation, using a single beacon (or a transponder). We propose a solution to estimate the underwater vehicle position in the presence of unknown ocean currents. The main idea is to combine the dead-reckoning information with multiple range measurements taken at different instants of time from the vehicle to a single beacon. Then, applying a multilateration based algorithm and using a Kalman filter, the unknown velocity of ocean current and a more accurate estimation of vehicle's position is estimated. The stability and convergence of the position estimation error are analysed taken explicitly into account the presence of ocean currents, disturbances, measurement noise and discretization errors. Simulation results are presented and discussed. In particular, we show that the implementation of the Kalman filter to estimate the ocean current is crucial to achieve convergence of the estimated position.