The Research And Realization Of Location Technique For Wireless Sensor Networks Based On ZigBee

With the rapid development of theoretical knowledge of wireless sensor networks in related fields, wireless sensor network positioning technology get a wide range of applications in forest fire prevention, environmental monitoring and military defense. However, due to the complexity of the various environment, the nodes transmit power limit, electromagnetic interference and communication distance, which will seriously affect the accuracy of RSSI values, thus affecting the positioning accuracy. So how to make the wireless sensor network to adapt to different environments, eliminate the influence of other factors on the target, which is targeting wireless sensor networks have an important role.This paper based on the research literature and a large number of sensor node design, through IAR and Altium Designer software designed hardware platform and software platform for wireless sensor nodes. Hardware platform includes a peripheral boards and RF modules, development board is composed of the liquid crystal display module, key module, TI CC2520 RF modules and other components. Software platform design includes unknown node software design, software design reference node and gateway node software design, meanwhile the algorithm is performed on the development boardAiming at the Static Weighted Centroid Location cannot get accurate positioning accuracy, this paper present a new algorithm-Adaptive weighting localization algorithm based on RSSI. Since RSSI value is directly related to the accuracy of positioning, and RSSI ranging affected by the communication distance and other factors, aiming at the problem this paper present RSSI optimization algorithm. Firstly we make initial average value for the collecting RSSI, Secondly the RSSI value is set by the Gaussian filter, filter out the small probability even and make the second average value for the RSSI, Finally, the optimization algorithm remove parameter's influence by formula derivation, the way can eliminate errors of different node's power and other factors. Due to the static weight positioning algorithm weighting factor is fixed, this paper let reference node adaptive get optimal weight correction factor. This algorithm judge the difference between the two groups distance, if the result exceed 1.5m, This algorithm analyze the node derivative of the unknown node location formulas positive and negative values, if the result of derivative value is a positive number or negative number,so the weight correction factor increase(decrease) in the interval gradually, all of this is finding the optimal weight correction factor which he difference between the minimum distance corresponding.Finally, we verify the feasibility of the new algorithms by the MATLAB simulation platform and experimental tests. We analyze positioning accuracy of different factors such as the different of reference node, communication radius and path attenuation coefficient. Meanwhile, we set up a small wireless sensor networks and analyze positioning accuracy of different real experiment scene such as indoor environment(College Hall), outdoor environment(Outdoor Football Field) and Underground tunnel. The new algorithm-Adaptive weighting localization algorithm based on RSSI has high precision positioning and feasible in practice by the Matlab simulation and experimental tests...