Localization Algorithm For Wireless Sensor Network Of Sparse Anchors

Node localization is not only one of the main supporting technologies of wireless sensornetworks, but also is the prerequisite and foundation of many applications in WSN, and thetechnology of node localization plays a key role for object monitor function in wireless sensornetwork. Currently, most algorithms use anchor nodes equipped with GPS to be reference points, butdue to the energy, cost and other constraints, anchor nodes are not suitable for mass deployment.When anchor nodes are sparsely distributed, most algorithms will promote positioned nodes as anchornodes directly to increase the number of reference nodes, but the method usually leads toaccumulation of localization errors easily.To solve the problems above, firstly this paper proposes an improvement of node promotionstrategy, which gives weight to reference nodes by their localization accuracy and describes unknownnodes’ positioning results with the weight.The weight consists of range error and reverse localizationerror.The improvement replaces range error of initial anchor nodes with all nodes’ range error andreverses the role of anchor nodes and unknown nodes,at last use reverse localization error to beanother part of the weight.The improvement of node promotion strategy will promote node withhigher weight to be anchor node and reduce the subsequent accumulation of localization errorseffectively.Secondly, we raise the two-point localization method to solve the issue of low location rate withsparsely distributed anchor nodes in wireless sensor network. After the implementation of three-pointor multi-point localization algorithm, we will apply two-point localization algorithm to the bad nodesof network, and use the collaboration of nodes within a jump to exclude the disturbing location so asto determine the correct position of unknown nodes. The two-point localization algorithm willimprove localization rate of node in network, and increase the range of network monitoring.Finally, this paper raises a new algorithm by applying the promotion strategy and two-pointalgorithm to RSSI, which named ST_RSSI. And MATLAB software is applied to simulate theST_RSSI algorithm. At last, simulation results show that the ST_RSSI algorithm can not onlyguarantee higher node localization rate, but also improve the localization accuracy obviously.