The Improvement And Implementation Of RSSI Location Algorithm In Wireless Sensor Network Based On ZigBee

With the rapid development of modern communication technology and embedded technology, wireless sensor network increases its scope and scale in applications. Positioning technology as an important application of wireless sensor network, has become a research hot spot.wireless sensor location network can be widely used in environmental monitoring, military reconnaissance and other fields. ZigBee provides a perfect solution for designing a wireless sensor location network. Therefore, This thesis has important practical significance. The core work and the purpose of this thesis is to improve the positioning accuracy for RSSI algorithm.The thesis expounds the research background and significance of its project. Then introduces some related theoretical knowledge Simply. Including:wireless sensor network system structure and protocol stack; IEEE802.15.4/ZigBee protocol stack; Wireless locating mechanism classification and localization algorithm evaluation criteria, etc.The thesis analyzes several typical localization algorithms'positioning principle detailedly, and points out the advantages and disadvantages for each algorithm; Finally,the thesis expounds three node coordinates calculation method. The thesis expounds two kinds of signal transmission path loss model briefly:The first is free space signal propagation path loss model. The second is logarithm normal distribution model.The principle and process of the traditional RSSI are analysed detailedly in this thesis, then the thesis indicates that several shortcomings of traditional RSSI algorithm and proposes two improved methods:The first, the thesis imports serveal irrelevant beacon nodes to involve the distant measurement between the blind node and the beacon node. The second, the thesis imports the centroid algorithm to involve the blind node coordinates calculation with trilateration. Finally, the thesis compares the improved RSSI algorithm's positioning error with traditional RSSI algorithm. The simulation data shows that the improved RSSI algorithm has a great improvment in positioning accuracy, but the time required to complete orientation also increased.Finally,The thesis implements a wireless sensor network positioning system based on ZigBee, which using RSSI localization algorithm. Emphatically analyses the principle of CC2431 hardware location engine and the data transceiver process between the three different type nodes. In the end, the thesis sets up and runs the WSN location system with the software named Z-Location Engine. Results show that the system achieved better location performance.