Localization Research In Zigbee Based Wireless Senor Network

With the development of wireless sensor networks, people began to realize the importance of moving object’s position information, the relevant services bring by determinate location information get attention, people began to do a lot of research on wireless localization methods and algorithms.Zigbee technology is one kind of wireless sensor networks technology, it get people’s favor on account of its low-speed, low-cost and low-power consumption characteristics, and it has been promoted heavily in the application of the wireless sensor networks, meanwhile it can meet the needs of localization system in my dissertation, so choose it as a solution.This dissertation introduce the development history and status of wireless sensor networks localization in domestic and overseas, illustrates the background and significance of topics, designed wireless sensor networks localization system based on Zigbee, the design of both the hardware and the software of the localization system are all included.The essential of wireless sensor networks localization is the localization of blind node, the method which we use to localization blind is based on the Received Signal Strength Indication.The localization system consists of three types of nodes: reference node, blind node and coordinator node.Among them, coordinator node is the core part of the human-computer interaction, made up of a CC2430 chip module, blind node uses a CC2431 chip module which built-in location tracking engine, reference nodes uses CC2430 module chips and deployment in the known position by artificial, reference nodes and blind node in networking.Two kinds localization algorithms of different localization mechanism are described in detail:range-based localization algorithms and range-free localization algorithms.Thr-ough the comparison of several localization algorithms, in order to meet the requests of localization system in this dissertation, such as low-cost, low-power consumption and easy achievement, etc.we choose the localization algorithms based on RSSI, RSSI localization algorithm is researched and analyzed, introduced three kinds of Blind node coordinate calculation methods at the same time.Due to the different of actual circumsta- nces and the ideal situation in theory, there will always be location error, so we improve the RSSI localization algorithm from ranging phase and coordinate calculation phase.Introduced average model and Gaussian filtering model in the range phase, it reduced the influence of rare pro-babilityand large interference events, so promoted the accuracy of the measured value.In coordinates calculation phase, improved the three-bonier measurement combine the actual circumstances in order to reduce the localization erro.The results of Matlab simulated experiments verified the effectiveness of improved localization algorithm.Finally, built the localization system based on Zigbee by the existing laboratory equipments, experiment and record the data.Based on the analysis for the experimental data, gain the comparison results from improved three-bonier measurement with the other two localization algorithms, the experiment results agree with the Matlab simulated experiment.which indicate that the research method is valid.Confirmed that the improved localization algorithm can promote the location accuracy by the experiments, demonstrate its feasibility.