Error Analysis of a Distributed Node Positioning Algorithm in Underwater Acoustic Sensor Networks

In this paper, we study the problem of distributed and passive node positioning in the underwater environment. Since the underwater sound speed is depth-dependent, the transmission path of acoustic signals is non-straight. In the distributed node positioning algorithm, we consider the depth-dependent sound speed, and relate the horizontal distance to the acoustic signal propagation time between the anchor and underwater node. Using information from at least three anchors, the underwater node estimates its horizontal location. Moreover, we analyze the impact of several factors, namely the time delay estimation error, the anchor's location estimation error and the sound speed estimation error, on the performance of distributed node positioning algorithm, in terms of the localization error. Simulation results show that the effect of analyzed factors on the localization performance is sensitive to the position of the underwater node. Moreover, among the considered factors, the effect of the sound speed estimation error on the localization performance is the worst.