| With the rapid development of Internet technology, wireless sensor networks gradually affect all aspects of people's life. The applications expand from military to agriculture,manufacturing,transportation,environment,engineering etc. At the same time the structure of wireless sensor networks have shown the private network,cellular networks,wireless ad-hoc networks etc. The importance of node location information in network nodes determines positioning technology for wireless sensor networks is one of the main supporting technologies. Positioning technology has become a research hotspot.On the basis of describing the existing positioning technology,the representative location algorithm and location system, This paper analyzes the limitations of existing algorithms. Wireless sensor network possess three characteristics,which is the low proportion of the beacon nodes, beacon nodes distributed unevenly, and the limited communication radius . This leads the existing algorithms is not fit for the network with low ratio of beacon nodes. Aiming at the problems of the low localization accuracy and low localization rate of coverage in wireless sensor networks (WSNs) where the density of anchors is low, an improved algorithm called HCAPIT based on multi-hop Convex positioning algorithm and APIT is proposed, The algorithm makes use of the K-hop neighbors information of the unknown node beacon node, adopts the Perfect Point-In-Triangulation test to estimate the probable area and reduces the area through multi-hop Convex.Based on the design algorithm flow, we establish an appropriate system model and simulation model. The simulation validates the algorithm performance respectively from the ratio of beacon nodes, communication radius, the error distribution, the total number of nodes in the network. The simulation results show that the improved algorithm is more suitable for the network where the node density is low. The lower beacon node density , the greater effect of location. |
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