Research Of Indoor Positioning System Based On Zigbee Wireless Network

Since quickly and efficiently obtain the target position information and provide location-based services, which is the prerequisite and basis for monitoring and control of wireless sensor networks' s events, the technology of node localization is one of WSN's key technologies. Zigbee as one of new low-rate and short-range wireless network technology, which is featured with low power dissipation, low cost, high safely, and low latency, meet wireless sensor network's demand, and especially is suitable to indoor and small-scale localization. This article has designed a Zigbee-based wireless senor network indoor positioning system after a thorough study on Zigbee and wireless positioning technology. Main summaries are listed below:1.The article has summarized status of Zigbee and indoor wireless positioning technology, given a detailed instruction to several common positioning algorithms about their principles and characters, and provided measuring index for positioning algorithm performance. CC2530-centered Zigbee has been chosen as the wireless sensor network positioning platform and detailed introductions to design of software and hardware have been conducted.2.Based on previous algorithms, this article has perfected two different types of RSSI-based positioning algorithms. For the first algorithm-maximum likelyhood estimation, an appropriate weight matrix has been selected out through theoretical analysis and simulation. For the second algorithm-triangle weight centroid positioning algorithm, unreasonable weight value has been analyzed, with the ratio of the distance between nodes instead of the reciprocal of the distance as weight value and simulation experiments have been conducted under Matlab environment.3.Modified triangle weight centroid positioning algorithm has been tested integrally, including two stages: distance measurement stage and positioning stage. In distance measurement stage, RSSI-based distance measurement model has been adopted in this article for the sake of system cost, power dissipation, node size, and practicability of RSSI-based distance measurement system. In order to offset disturbance by environment factors, an error compensation mathematical model has been put forward by curving filling. In positioning stage, the paper completed theparameter calibration of PC and PC code of positioning algorithm written in Visual Basic6.0 development environment. PC called the positioning algorithm to calculate coordinates of mobile node.The positioning system has been analyzed in position accuracy, power dissipation, cost, fault tolerance, and adaptivity, suggesting that error of the positioning system controlled within 1.5m and performs well in positioning effectiveness, showing low power dissipation and cost, and high fault tolerance and adaptivity, and exhibits some theory and application potential.