Research Of Indoor Positioning Technology Based On Wireless Sensor Network

With the rapid development of mobile Internet, location based services(LBS) have become more and more indispensable in people’s daily life. And indoor localization is the premise and key to implement LBS.Satellite navigation systems have been widely used in outdoor LBS service. But satellite signal can not penetrate the interior walls and other obstacles, satellite navigation systems can not get satisfied localization performance, which restricts the development of indoor LBS. Indoor positioning technology based on wireless sensor network can make up for the deficiencies of GPS,which can provide real-time location and navigation information for underground parking and other places.Due to the need of extra hardware, the overhead of the state of art of indoor localization technology is pretty high and it is hard to popularize. But received signal strength indicator(RSSI) based indoor localization does not need any additional equipment, which can be obtained directly during wireless communication. Therefore, RSSI based indoor localization has become the first choice for indoor positioning research.Based on the analysis of the localization algorithm in Wireless Sensor Networks, two indoor localization algorithms are investigated and studied deeply. One is based on RSSI ranging, the other is based on fingerprint. Contents and contributions of this paper are summarized as follows:(1) Propose an adaptive piecewise curve fitting algorithm based on the study of signal propagation model. The experiment results show that the proposed algorithm has better positioning precision and better environmental adaptability.(2) Study the existing location algorithm based on fingerprint. Analyze the impact of the pretreatment methods of raw RSSI, the measures to solve neighborhood, k neighbor selection and the methods of obtaining position coordinates on positioning accuracy for determining the optimal positioning algorithm for indoor environment.(3) Design a indoor prototype system based on wireless sensor network, which can choose different indoor localization algorithm. The experimental results show that the improved algorithm based on RSSI and the optimized algorithm based on the fingerprint have higher positioning accuracy.