Wireless Sensor Network Node Location In Large Public Places

As the global positioning system(Global Positioning System,GPS)as the representative of the satellite positioning technology has been able to open even in the outdoor environment to provide high-precision positioning services,but in indoor and underground closed environment,because of the influence of satellite positioning signals by obstacle,multipath propagation and other factors,it is difficult to effectively locate.And wireless sensor networks(Sensor Network Wireless,WSN)positioning technology has become an important research direction in large-scale indoor public places because of its low cost,easy to implement and strong anti-interference.Because it has many advantages,since the mass organization,a variety of perception,strong robustness and high fault tolerance,has been widely used in many fields of military,medical,intelligent Home Furnishing of industry and agriculture,disaster management,etc.Positioning technology is one of the most important and indispensable technologies in almost all application scenarios.In localization technology of wireless sensor network,it is more applied to the location technology based on distance measurement(Rang-based)and the localization technology based on non ranging(Rang-free).Range based localization technology is the need for direct measurement of distance or angle space between the nodes in the information,and then to determine the location of network nodes through the relevant geometric algorithm,the positioning accuracy is relatively high,but the high requirement on hardware;and based on the positioning technology range is relatively simple,not the actual distance between the measurement of nodes,the cost is relatively low,so its development is very rapid.This paper focuses on the research and improvement of the DV-Hop location algorithm in Wireless Sensor Networks:in-depth study and analysis of the positioning demand for large public places and the classic non ranging location algorithm DV-Hop.resulting in the distribution ratio between the beacon nodes in positioning monitoring area distribution ratio and between beacon nodes and unknown nodes is not balanced,the average distance of each hop is not suitable for the calculation of node coordinates;a nonlinear least square optimization algorithm based on fixed beacon nodes is proposed,which is called Rectangular(Hybrid DV-Hop RHDV-Hop).The error sources for DV-Hop localization algorithm the new algorithm,mainly to make the optimization and improvement of the following:first,the traditional random throwing the node layout to the beacon node fixed form beacon node ring in the monitoring area periphery;secondly,according to the beacon nodes and unknown nodes deployment ratio,namely the average hop number,select the right of the average distance of each hop as the global average distance per hop distance calculation;finally,using nonlinear least squares optimization algorithm Levenberg-Marquardt to optimize the calculation of the unknown node coordinates.Simulation results show that the RHDV-Hop positioning algorithm is more suitable for large indoor public places,and the positioning accuracy is significantly improved compared with the original algorithm.