The Research Of Localization Algorithm Assisted By Mobile Beacon In UWSN

With the rapid development of wireless sensor networks and underwater communication technologies,the demand of high-precision positioning for underwater targets is also increasing day by day.Important role is played in many other fields,such as navigation,marine environment monitoring and resource exploration.However,acoustic signal has problems in the underwater environment,such as large propagation loss and multipath effects.The anchor node as a reference node is placed in underwater,so the energy carried is limited and deployment and recovery is difficult.As a result,requirements of various fields for underwater target positioning are cannot fulfill and there are problems in localization in UWSN,such as low accuracy and high energy consumption.Due to the development of underwater vehicles and AUV in recent years,localization assisted by mobile anchor node has become an effective way to solve the problem of underwater localization.In this paper,two positioning algorithms are proposed to implement the positioning in underwater wireless sensor networks,which is based on the characteristics of underwater acoustic signals and using the excellent performance of mobile anchor nodes.The research results of this paper not only can provide the basis for high-precision positioning in underwater wireless sensor network,but also promote the high-precision underwater positioning technology development,and have high scientific value and practical significance.The main research of this article includes the following aspects:Firstly,a localization algorithm using a mobile anchor nodes based on region determination in UWSN is proposed,which aims at the existing problems of the UWSN localization algorithms.This algorithm is divided into two stages:region determination stage and location positioning stage.In the region determination stage,the target region is divided into several sub-regions by the region division strategy with the smallest overlap rate which can reduce the number of virtual anchor nodes and lock the target node to a sub-region.The path planning of mobile nodes optimizes the travel path and reduces moving distance,so system energy consumption is reduced.In the location positioning stage,the target node location can be calculated using the HILBERT path planning and trilateration.Secondly,aiming at the problem of large positioning error caused by unidirectional localization in LMRD algorithm,an UWSN positioning algorithm based on group mobility anchor nodes is proposed.This algorithm uses multiple mobile anchor nodes to improve the efficiency of the positioning process and the accuracy of positioning results.Based on the regional division of the UWSN node localization algorithm assisted by mobile anchor nodes,the positioning algorithm further reduces the localization error caused by unidirectional positioning.The positioning mechanism of the algorithm can be divided into three sub-regions determination,initial positioning and iterative location estimation.In the sub-region determination stage,the four mobile anchor nodes form a diamond shape and use the SCAN path planning to move.In the initial positioning stage,a preliminary calculation value of a target node is obtained according to different regional determinations.According to this coordinate,the mobile anchor node moves within the sub-region and the position of the target node is iteratively calculated.Through experimental verification,the localization algorithm using a mobile anchor nodes based on region determination in UWSN not only reduces the energy consumption,but also improves the accuracy and efficiency of the positioning process.However,this positioning algorithm results in large positioning error due to the uni-directional positioning of sub-region edge conditions.Therefore,an UWSN positioning algorithm based on group mobile anchor nodes is proposed in this paper.Through simulation and verification,this algorithm not only reduces the positioning error caused by unidirectional positioning,but also improves the positioning accuracy and improves the positioning efficiency.