Design And Implementation Of An Indoor Localization And Tracking System Based On Short-Range Wireless Communication

Location-based services continue to enrich people's production and life,and are widely used in various fields such as traveling,logistics,and marketing,etc.The localization system based on the global positioning system can achieve high-accuracy in open outdoor scenes.It basically meets people's demand for positional information when they are outdoors.However,indoor localization is restricted by factors such as environment and cost,and there are greater technical challenges.Indoor localization based on short-range wireless communication has become particularly prominent because of its many advantages.At the same time,with the development and popularization of smart terminals,localization based on inertial sensors of smart terminal has also become one of the important indoor localization technologies.Therefore,for indoor localization and tracking technology based on short-range wireless communication,this article mainly studies iBeacon technology and pedestrian dead reckoning and new algorithms are proposed to improve localization accuracy.Firstly,based on iBeacon positioning,this thesis proposes an improved weighted centroid trilateration algorithm employing GDOP(Geometrical Dilution of Precision).Because the ranging algorithm based on the received signal strength indicator is easily influenced by signal propagation problems,the traditional trilateration algorithm may have complicated positioning geometric models and unreasonable reference point structures,which could lead to difficulties in position solving.This thesis proposes a calculation method for indoor GDOP,which can measure the error of indoor localization algorithm,to assist the selection of reference nodes and to participate as a weight factor in the improved WCT(Weighted Centroid Trilateration)algorithm.Secondly,based on the proposed improved iBeacon positioning algorithm,this thesis further designs and implements an integrated navigation scheme based on iBeacon/PDR(Pedestrian Dead Reckoning).This scheme combines the advantages of iBeacon positioning and PDR with the Kalman filter,which can ensure a high consistency and high precision of the output trajectory of the system.Meanwhile,a self-adaptive stride-length is also proposed in this thesis to prevent the PDR from drifting too much.Furthermore,a CUPT(Coordinate Update)algorithm is proposed to eliminate the cumulative error of the integrated navigation system,which further improves the localization accuracy.Finally,this thesis designs and implements an indoor localization and tracking system based on the integrated navigation algorithm mentioned above.The system mainly contains a resolving server,an indoor map webpage and a WeChat applet.This system was deployed in a practical scenario,and the performance of the indoor localization and tracking system was verified by practical tests.Field test results show that,in the experimental environment,the localization algorithm proposed in this thesis can achieve an average localization accuracy of less than 1 meters.