Outlier rejection for autonomous acoustic navigation

Navigation is a critical requirement for the operation of autonomous underwater vehicles (AUVs). In this paper we present acoustic navigation results for the Odyssey II AUV obtained by using a Kalman filter that integrates dead-reckoning with acoustic range measurements made to an array of acoustic beacons pre-deployed in the operating environment. Because spurious acoustic measurements due to multipath propagation are common, initialization and outlier rejection techniques are addressed. The navigation algorithm has been extensively tested by post-processing of real data acquired by Odyssey II during field operations in a variety of environments. These include the Charles River Basin, the Atlantic Ocean (1.5 km off the Florida coast), and the Pacific Ocean (375 km off the Oregon coast). Our results show improved performance over prior techniques based exclusively on fix computation and dead reckoning