Cooperative Localization and Unknown Currents Estimation Using Multiple Autonomous Underwater Vehicles

This letter is on cooperative localization and sea currents estimation using multiple Autonomous Underwater Vehicles (AUVs). Due to sea currents, dead reckoning localization based on inertial navigation sensors results in accumulation of localization error. To reduce the error accumulation, this letter proposes navigation algorithm to allow multiple AUVs to simultaneously estimate their navigation states and unknown sea currents. This letter introduces the fusion of Unscented Kalman filter and linear Kalman filter for joint estimation of the navigation states and unknown sea currents. Suppose that only one AUV, called the leader, is equipped with Doppler Velocity Logs (DVL) and Ultra Short Base Line (USBL) sensors. To improve the localization of multiple AUVs, the leader measures both the bearing and the range of its nearby AUV periodically. As far as we know, this manuscript is unique in considering cooperative localization of multiple AUVs in unknown currents. The effectiveness of this cooperative localization is verified using MATLAB simulations.