Research On Local Cooperative Localization Algorithm In Wireless Sensor Networks

With the rapid development of wireless sensor network technology, itsapplication has been involved in various fields, including military, agricultural,industrial, environmental protection, Health care, intelligent transportation, buildingdetecting, and space exploration. Nodes’ location information is the supportingtechnology of routing protocol, topology control, safety technology and othertechnical, if they lose the position of the nodes, the other functions will lose theirmeanings.The main target in this paper was to improve localization algorithm for wirelesssensor network coverage and positioning accuracy. Anchor node optimization basedon RSSI localization algorithm and Local cooperative localization algorithm had beenproposed. The main contents are as follows:Firstly, the concept, characteristics and system structure of wireless sensornetwork is described. Then it is elaborate to describe the basic principle, classificationmethod, procedure, the performance evaluation standard of location algorithm and theclassical positioning algorithm.Secondly, deeply study and analysis of the RSSI location algorithm. RSSI signalvalue is constantly affected by environmental factors, such as temperature around thenodes, humidity and light intensity, signal interference and so on. In order toovercome the shortcomings of RSSI-based location algorithm anchor nodeoptimization based on RSSI localization algorithm is proposed by combining thecharacteristics of the lognormal distribution model. This algorithm for calculating thelocal path loss exponent and setting the threshold condition of error can removeinvalid anchor nodes which are affected by the environmental factors. The nodes canbe known its location accurately by more effective anchor nodes which are filtered.Again, this article elaborates the concept of cooperative thought, the main reasonand targeted content for the introduction cooperative thought, and then localcooperative localization algorithm is proposed. The idea of cooperative localization is introduced into RSSI localization algorithm and setting the threshold condition oflocal path loss exponent. Nodes that meet certain requirements of localization errorwould be upgraded to anchor nodes to take part in localization of other nodes andimprove coverage rate of localization. That can reduce the cumulative error generatedin localization and ensure the accuracy requirements of the application.Finally, simulate this localization algorithm by the Network Simulator Tool inLinux environment. That determines the optimal error threshold in anchor nodeoptimization based on RSSI localization algorithm. The conclusions can reached: theaccuracy of anchor node optimization based on RSSI localization algorithm is betterthan the traditional RSSI and RSSI location algorithm improved positioningalgorithm; Local cooperative localization algorithm of wireless sensor networkperforms well on nodes’ localization accuracy and coverage rate compared with thealgorithm of improved RSSI localization, MDS-MAP and cooperating localization.