Research On Underwater 3D Localization Assisted By Mobile Node

Localization is one of the most crucial issues in the art of underwater acoustic sensor networks.In exiting localization technology,the range-free localization strategy generally has a low accuracy,and the range-based localization method tends to bear extra cost due to distance measurement,while the result of RSSI-based scheme is always not precise enough.In this paper,the attenuation characteristics of the acoustic signal spreading in the underwater channel are analyzed,and the variation law of the RSSI received while the beacon node moves is observed,accordingly a new ranging approach is proposed.Different to traditional RSSI-based ranging scheme which is aiming to measure the node-to-node distance,the range scheme in this paper targets measuring the distance between node and the trajectory by employing the Support Vector Regression(SVR)to process non-linear data with the aid of the moving beacon node.Combining the optimized moving path of beacon node,we proposed two localization strategies for 3D underwater space,which are node-to-trajectory range-based algorithm and projection-based algorithm.The node-to-trajectory range-based algorithm calculates the coordinates of nodes based on the distances from the node to the two trajectories surrounding the node,while the projection-based algorithm locate the node with the projection of the node on the moving path and the corresponding node-to-trajectory distance.In this paper,the proposed localization schemes do not need extra devices or process of network synchronization;they also avoid the shortcoming that precision declining due to the disturbed by noise in traditional RSSI-based scheme.In the end,the simulation results show that the accuracy of distance measurement reach a high level,which is benefit from processing of a large number of RSSI.As the final result,the localization algorithms achieve excellent performance.