Node Localization In Underwater Wireless Sensor Networks

Underwater Wireless Sensor Networks(UWSNs)are a crucial monitoring tool in ocean resource exploration,environmental monitoring,and underwater communication.However,node localization in UWSNs is challenging,especially when influenced by natural environmental factors such as ocean currents,which can result in significant location errors and greatly impact the network’s effectiveness.In response to the aforementioned issues,this paper considers factors such as ocean current models,variations in sound velocity,loss of measurement information,and propagation delay,and proposes a mobile node(super node and ordinary node)localization technique.The main research contents of this paper are given as follows:Considering the dynamic node localization problem in ocean currents,the super node localization algorithm based on frequency domain analysis and the weighted fusion algorithm for ordinary nodes based on depth information is proposed.First,a depth-related ocean current model is proposed by combining the dynamic characteristics of ocean currents with actual ocean current data.Based on this ocean current model,frequency domain analysis and particle swarm optimization are used to predict the location of the super node.Then,based on the broadcast information of the super node,the information fusion localization algorithm based on depth is designed to achieve localization and prediction for ordinary nodes.Considering the problem of mobile node localization in a medium with varying sound velocity,a minimum residual localization algorithm based on sparse feature points extraction is proposed.Considering the non-linearity of sound speed based on the current model,the algorithm models the sound speed curve and linearizes it by extracting sparse feature points.The propagation time required for signal transmission is then calculated using the time of arrival model.Finally,the minimum residual localization algorithm based on the sparse feature points is utilized to achieve node localization in a non-linear sound speed environment.Considering the issue of measurement information loss during underwater communication,the localization algorithm based on target prior information is proposed.In addition to considering the ocean current model and non-linear sound speed,this algorithm also takes into account the possibility of measurement information loss.When measurement information is lost,the velocity of the target is predicted using prior information,which provides an estimated range for the target.Then,by combining the received measurement information with the motion range obtained from the prior information of the target,the algorithm uses the sparse feature pointsbased minimum residual localization algorithm to achieve node localization.This approach enables ordinary node localization in the loss of partial measurement information.Considering the localization problem in UWSNs containing mobility-constrained node under delay conditions,the delay compensation algorithm and the particle system-based ordinary node localization algorithm is proposed.Firstly,model the mobility-constrained nodes according to their characteristics.Then,based on the current model,the delay compensation algorithm is proposed to address the delay problem in the straight-line propagation path.Finally,considering the above factors,the particle system-based ordinary node localization algorithm is proposed to enable the mobility-constrained nodes to participate in ordinary node localization in a more accurate modeling way.Simultaneously,the impact of propagation delay on localization is mitigated.This paper considers the influence of the marine environment on the localization of moving nodes in UWSNs from multiple aspects and proposes corresponding solutions.They are expected to provide technical references for environmental monitoring and target localization in UWSNs.