Wireless Network Sensor Positioning Algorithm Research

As a new technique in information acquisition and processing of nowadays, Wireless sensor networks(WSN) which is famous for it effective and convenient property can be wildly used in many areas such as, environmental supervision, medical treatment, traffic control, national defense, out space exploration , and so on. Self-localization is one of the indispensable supporting techniques in wireless sensor networks, and had widely drawn attention of researcher and scholars.Many wireless sensor of networks applications are based on accuracy of sensor self-Positioning. Because of constraints in size,the investigation of efficient location algorithms which satisfy the basic accuracy requirement should meet the problem of limited Power,and cost of construction of sensor nodes ,that is the great challenge of WSN.In the recent investigation the location technology for WSN can be categorized to two kinds: Range-based approaches and Range-free approaches. Range-based methods have better accuracy,but require additional hardware at the sensor nodes,for it high energy cost and expensive equipments makes it unavailable on regular application fort of sensor networks. Which is wild located with a lot of node in it. Acknowledging that the cost of hardware required by range-based solutions may be in appropriate in relation to the required location precision,researchers have sought alternate range-free solutions to the localization problem in sensor networks. Because of the hardware limitation of WSN devices,solutions in range-free localization are being pursued as a cost-effective alternative to more expensive range-free algorithm makes no assumption about the availability or validity of range information. In allusion to the special self-organizing network WSN, range-free has been abroad attended by the scientific researcher. Because of the advantages on power and cost on sensor node, the thesis focuses on investigation of range-free algorithm for WSN.First of all, the research status of wireless location techniques and positioning systems for WSN are summarized based on the study of a lot of related literatures; follow by the system structure and soft-hardware of network node for WSN are summarized; also referring the inherent and bright characteristic knowing from the other wireless network and introducing the wide application value.Secondly, localization modes of network node are analyzed; and mainly introduce representative several arithmetic, which have been compered. The analyse the novel localization algorithm APIT which is based on lapped area and its disadvantage, and put forward a improved algorithm RCENTROID ,base on the RSSI and CENTROID arithmetic .which is presented and simulated, the results show that it has the better positioning accuracy , but less communication overhead and more compute time than CENTROID . Furthermore, this paper analysed the character of map-growing algorithm, and drawbacks of it .then brought Least Squares method in the map-growing algorithm and form a improved algorithm which names map-growing+ algorithm. The result of the simulation indicated that the new algorithm is more effective than the origin one.At last, this paper makes a conclusion for this dissertation. And foresee the future of the MSN location algorithm.