Research On AUV-Aided Localization Scheme For Underwater Wireless Sensor Networks

With the rapid development of information technology and network technology, wirelesssensor networks flourishes. Due to the water area of earth is abundant and the research field isexpanding, there is a greatly interest in exploration of underwater wireless sensor networks.Underwater wireless sensor network has limited communication capabilities, the deployment ofsensor is randomly and the energy of sensor node is limited. This is the same as terrestrial wirelessnetworks. Underwater environment is different from terrestrial environment as following: The radiocommunication is unfit for underwater because the radio signal underwater is easy to appear thephenomenon such as reflection, refraction and diffraction. Therefor GPS can not be appliedunderwater, all above unique features will cause grand difficulties in the research and design ofUWSN.The position information of sensor nodes is the basis of sensor networks protocols andapplications, it can not only help the network to achieve load balancing and the automaticconfiguration of the tology, but also provide technical support for routing, topogy control and targettracking. Based on the analysis of existing underwater wireless sensor network localizationalgorithm, and the present situation of the positioning error of nodes underwater is still large, thispaper proposed an localization algorithm based on the selection of beacon nodes and AUV-aidlocalization algorithm. The algorithm set the weight of becon nodes according to RSSI received byunknown nodes, proper beacon nodes can be selected according to the weight in order to improvethe positioning accuracy, at the same time, the algorithm introduce AUVs to assist the UWSNlocalization, the localization accuracy of every unknown node is estimated based on the number, thedistribution and the distance of neighboring beacon nodes. Accordingly, some nodes with loweraccuracy are filtered out, then AUVs will give assistance to the secondary positioning of thesenodes. Thereby the algorithm can effectively improve the location accuracy of nodes, and reduce thecomputation and complexity of this scheme.The results of simulation experiment and theoretical analysis on the above algorithms suggestthat these algorithms can improve the positioning accuracy effectively, moreover, the computationand complexity of this scheme are proven preferable as well. Finally, we designed and implementeda prototype system of wireless sensor networks for environmental monitoring of water, theAUVs-aid algorithm is validated, and the system test show the AUVs-aid algorithm has practical feasibility.