Research On Wireless Sensor Networks Localization Technology Based On RSSI

With the rapid development of micro electro mechanical systems, sensor technology and wireless communication technology, a network called Wireless Sensor Network(WSN) which possess of information collection, transmission and processing capabilities was established. WSN, as a new kind of wireless data processing platform, has made such a great progress in theoretical research and practical application(e.g. military defense, industrial and agricultural control, urban management and et al.). Node localization technology as one of the key technologies of WSN, not only can effectively improve the efficiency of the network route and network management, but also the premise and foundation for most applications such as target tracking, personnel positioning and environmental monitoring. Therefore, WSN self-localization algorithm and related technology research remains challenges to be solved.The existing WSN localization algorithms based on RSSI are susceptible to multipath propagation, NLOS and other interfering factors, all of this result in increasing the distance measuring error, reducing the positioning accuracy and other issues. On the basis of full investigation and research progress, this paper intensively study a novel node localization algorithm with high precision and good stability, by using a combination of node localization and coordinate correction. Main research works are summarized below:(1) Existed basic maximum likelihood estimation(MLE) often has low precision and poor convergence. To solve above problems, this paper improve the initial positioning algorithm by using the constraint conditions which consisted by the RSSI values of the current time and the regional restriction circular which the center is the node coordinate of the previous time. The simulation results show that the improved algorithm not only improves the convergence of initial localization, but also increases the accuracy.(2) In the coordinate correction stage, we analysis the Insufficient of EKF filter technology and propose an AIUKF algorithm based on UKF filtering technique, iterative idea and adaptively robust filter theory, and directly using RSSI as observed quantity of the localization system, reduce the error accumulation in the ranging process. The proposed algorithm effectively reduced the influence of initial value fluctuation and measurements of abnormal value by using iterative algorithm and an adaptive factor. The simulation results show that the localization algorithm based on AIUKF not only improves the localization accuracy, but also enhances the convergence of localization results.