Integration of Range, Bearing and Doppler Measurements from Transponders into Underwater Vehicle Navigation Systems

Long Base Line (LBL) systems for surface and underwater navigation have been used for a long time. Methods for navigating with a single transponder have emerged over the last decade, and enable less costly transponder deployments. This paper discusses utilization of the information available from the transponder signal: range, direction and speed. These measurements are non-linear in nature. The choices of update methods, handling these non-linearities, are important when combining them with a navigation system. Extended Kalman Filter (EKF), Sigma Point Kalman Filter (SPKF) and ad-hoc methods are developed for this and tested in typical AUV scenarios. The results show that all three measurements can be used individually to aid an inertial navigation system. The quality of navigation is highly dependent on the trajectory of the vehicle. Also the choice of update method is important to the navigation quality when the initial uncertainty is high compared to the range to the transponder. Navigating with range and/or differential range to a sole transponder will give an accuracy almost down to the limit set by the transponder localization