Improvement of Localization Algorithm for Wireless Sensor Networks Based on DV-Hop

DV-Hop localization algorithm is a typical representative of range-free algorithms, which can be applied to large-scale wireless sensor network location monitoring with random distribution of nodes, such as geological hazard monitoring, water pollution monitoring, forest fire monitoring and more. In order to get a higher positioning accuracy, a new method is used to determine the average hop distance of anchor nodes firstly. Secondly, the estimated distances between nodes are calculated by using the correction value corresponding to the average hop distance; finally, in the positioning stage, when the number of anchor nodes is small, the Min-Max (Minimum-Maximum) method is used to obtain the estimated coordinates; on the contrary, the ML (Maximum Likelihood) method is used to calculate the estimated coordinates. One is to reduce the amount of calculation; the other is to keep the accuracy stable. Finally, the Quasi-Newton method is used to iteratively optimize the coordinates of unknown nodes. The results indicate that the accuracy of algorithm is about 15%-20% higher than that of the original DV-Hop algorithm.