Design And Implementation Of Indoor Location System Based On The ZigBee Network

WSN changes the way of exchanging information between us and the objective world, so that we can easily perceive the natural. Layout and coverage, node localization, network communication protocols are several basic problems in WSN research. With the progress of information and intelligence, People’s demand for location is inereasing. Especially in complex indoor environments,such as the office building, mine,underground parking, warehouse, airport hall and so on,the indoor location information of related personnel and valuables need to be identified.But as the limitation of the complexity of the indoor environment conditions, location accuraey and location time, well-location technology is still unable to be used in an encloseure spaee.In recent years, ZigBee technology arises gradually for its low-power and low-cost characteristics, resolving some problems of indoor location perfectly.On the basis of previous location technology, accomplishing the design of indoor location system based-on ZigBee.Firstly, based on the actual needs of the project, showing an overview of the research background and significance of this paper, then giving an presentation for the current status of WSN location technology based-on ZigBee describing the characteristics, structure and protocol stacks of WSN deeply.Secondly, deeply researching the location technology. Location requires to compute the location of the nodes, so Firstly, introducing several methods about inter-node distance measuring and deriving its’formula; then analyzing the principle and step of location, location algorithm classification and evaluation criteria, and finally describing several typical localization algorithm based on the RSSI location, TOA location, TDOA location, AOA location and centroid location, and simultaneously analyzing their respective range of applications. Then, this paper presents the idea to improve the RSSI location algorithm. First, it estabshes signal propagation loss model; then deeply analyzes the defects of the traditional RSSI location algorithm and proposes an improved method for defects, and carries on derivation about mathematical theory, and then describes the execution order of the improved RSSI location. Finally, gives a quantitative comparative analysis of RSSI algorithm before and after improvement, and then simulates through MATLAB. The simulation results show that the improved algorithm significantly improves the location accuracy of the blind node, completing the improvement of the RSSI location algorithm. Again, the paper accomplishes the design of ZigBee wireless location system, though setting up hardware and software platform of the system,building the structural framework of the ZigBee wireless location system. The system’s hardware design is based on the reasonable application of the CC2430/31chips, the CC2431module location principle, and the design of three network nodes. System software design mainly includes software development environment, Profile of wireless location-based applications and the process for sending and receiving data of wireless location systems, and finally focuses on the data flow design for ZigBee gateway node, the reference node and blind node. Finally, by building the platform and observing system operating conditions, giving the smallest system architecture of wireless location,using real-time location software to detect localization results for the reference node and blind node, which proves that it is of great rationality and correctness of the system design.