Research On Positioning Algorithms Of Underwater Sensor Networks Based On RSS

In recent years,the exploration and research of underwater environment has attracted more attention,while the accurate underwater positioning technology is a key to marine research.Due to the growing demand for high accuracy and low energy consumption for node positioning in Underwater Wireless Sensor Networks(UWSNs),existing underwater sensor network node positioning algorithms have the disadvantages of long positioning time,high energy consumption and low accuracy.To address these issues,the following research on the static and dynamic positioning algorithms of underwater wireless sensor networks are carried out:Firstly,the composition,application and characteristics of the underwater wireless sensor network,including the characteristics of the underwater acoustic loss channel and related parameters,are intensively studied.the existing common positioning schemes and strategies are summerized.The advantages and disadvantages of various schemes and application scenarios are analyzed.The above study lays a foundation for the research of underwater wireless sensor network node positioning.Secondly,for underwater static positioning,considerting the technologies based on the distance measurement,lower reqirements of equipment complexity and cost make Received Signal Strength(RSS)more attractive.However,RSS-based distance measurement has the characteristics of non-convexand non-linear.Therefore,a positioning scheme based on convex optimization is proposed.The least squares relative error is used as the node position estimation model.With the transmission power being regarded as unknown information,the node position and transmission power are jointly estimated.Furthermore,the Semi-Definite Programming(SDP)technology is used to transfer the estimation into a convex optimization problem,which is solved by the CVX toolbox in MATLAB.Simulation results show that this algorithm has better estimation accuracy for both of the the node positioning and transmission power.Thirdly,for underwater dynamic positioning,there is a large positioning error caused by the collinear problem in the positioning algorithm based on mobile anchor nodes.To address this problem,a UWSNs positioning algorithm based on dual-anchor SCAN path planning is proposed.The algorithm uses the master-slave mobile anchor nodes to traverse the monitoring area in parallel with the SCAN path,and jointly receives the information such as the IDs and RSSs of the unknown nodes.The master anchor node uniformly processes the RSS values of the unknown nodes and calculates their coordinates.The simulation results show that the algorithm not only improves the efficiency of the positioning process,but also has better performances on the positioning rate and positioning accuracy.