Localization Algorithm Of Wireless Sensor Network And Its Improvement Based On DV-Hop

Node localization technology is one of the key technologies in wireless sensor network. Range free algorithms play an important role in large-scale sensor networks, which especially has extensive application prospects in military, environment, intelligent space etc. DV-Hop localization algorithm is a typical representative of range free algorithms, which have many advantages including a simple positioning method, relatively high positioning accuracy, and relatively small computational costs. But the disadvantage of this algorithm is to use hop distance to replace the straight line distance and errors in randomly distributed wireless sensor networks which are relatively large. The study and research were done on the basis of previous research, and the main contents are as follows:1) Analyze the error factors of the original DV-Hop location algorithm and the algorithm in this paper which mainly include hop count, average hop distance, positioning calculation method. The classic improved DV-Hop algorithm was simulated and compared, which showed that the improvement of the classic improved algorithm was single and its location precision was insufficient.2) Aimed at the error brought about by the hop factors, the method of increasing hop threshold in the data packet format was put forward, which ensured to eliminate big location error data. The experimental result showed that rationally optimize the maximum hop threshold can improve the localization accuracy of 7% under the simulation environment in this paper.3) Aimed at the positioning error caused by the average hop distance, combined with average hop distance of anchor nodes after optimizing, the revised method of the average hop distance was put forward. And the simulation results show that, the improved method made full use of the information of anchor nodes after optimizing and had higher positioning accuracy compared with single anchor node.4) In the location calculation method, the improvements of the algorithm mainly include initial value estimation and final estimate of node coordinates. In the initial estimates,when the anchor nodes were less, the algorithm was solved with minimum and maximum(Min-Max) algorithm, when the anchor nodes were more,the algorithm was solved with least squares method. In the final estimation, use the quasi newton algorithm to iteratively optimize the initial value.The simulation results show that, the accuracy of algorithm is about 40% higher than the original DV-Hop algorithm, and about 15%-20% higher than the improved algorithm.