Wireless Sensor Networks Since The Localization Algorithm Research

With the development of the microelectronic technology, computer technology and wireless communication technoloy, wireless sensor network(WSN) has become a new kind of network. Localization is one of the key technologies in WSN. Since many applications of WSN depend on the location of sensors nodes, how to obtain the accurate location has become the focus the attentions. The thesis focuses on self-localization algorithms.In this paper, the main job is the following three aspects:Fristly the paper introduces the basic notion, syetem architecture, performance index of the algorithm and application field of the WSN. The representative algorithm of the WSN are summarized, what’s more, the advantage and the disadvantage of the algorithms are pointed out. The result will become the matting of the following research.Secondly the paper proposes an algorithm based on modifying weighted average hop distance. Only the average one-hop distance estimated by the nearest anchor was used in DV-Hop localization algorithm, but the value estimated by a single anchor can not reflect the whole network’s actual average one-hop distance. An algorithm is proposed to estimate the average one-hop distance based on weighted disposal. The average one-hop distance estimated by several anchors is used in this algorithm and assigned different weights according to the hops and the Environmental impact factors to the unknown node. The unknown node’s average one-hop distance is estimated more accurate and the localization precision is improved. Simulation results demonstrate that the average one-hop distance is estimated more exactly in the proposed algorithm than that of DV-Hop, and the location precision is more improved by two measures.Finnally the paper proposes two new algorithms:the Priority of the iterative weight centroid algorithm and the mufti-hops weight centroid algorithm.The weight centroid algorithm, which is range-free, has the advantages of low complexity and appropriate precision,But it performs well only with many anchor nodes. In this case, the former uses the located nodes as anchors and controls the cumulate of error by some methods; the latter exploits the anchor nodes n hops away in the localization. Simulation results demonstrate that they perform well in few anchor nodes case.