A Range-free Distributed Active Multi-stage Localization Algorithm

The appearance of underwater wireless sensor network gives researchers a greathelp on underwater environment observation and monitoring. It is meaningless for thecollected data without localization in some applications such as target tracking, disasterprevention.Considering the difficulty of distance measurement underwater, a range-freedistributed active multi-stage algorithm proposed in this paper. It is applied to therandom distribution topology network. It adds an average hops distance recalculation asthe estimated distance from unknown nodes to anchors based on the dv-hop whichreduces the localization error. The distributed pruning broadcast algorithm as anefficient routing table creation method prunes the previous node’s neighbors recursivelyin the next hop set. It decreases the unnecessary message’s forwarding counts. With themaximum likelihood estimation the modified distance estimation error reductionalgorithm can effectively enhance the positioning accuracy.Simulation results confirm that average localization errors reduce from sixty totwenty meters approximately. And the forwarding message count level is decreasedfrom exponential to linear which effectively prevents the network congestion, improvesthe energy conservation and extends the network lifetime.