The Study Of Ultra-Wideband Accurate Indoor Localization Technology Based On Wireless Synchronization

With the development of civilization,the indoor space for people’s activity becomes more and more complex and huge.The requirements for shopping center,airport and factory’s guiding and locating become increasingly fierce.The indoor localization technology has become a hot topic of research in recent years.Due to its high accuracy,anti-multipath fading and low power consumption,UWB technology provides a good solution for accurate indoor localization.Combined with the basic theory of UWB,the UWB localization technology has been deeply analyzed in this paper.In order to increase the number of tags that system can support,meet the requirement of low-power standard and considering the difficulty of wiring in complex indoor environment such as factory,the Time Difference of Arrival(TDOA)measurement method with wireless clock synchronization has been proposed.After analyzing several wireless synchronization methods,finally the Reference Broadcast Synchronization(RBS)has been decided.Also the Linear programming and Kalman filter are used for synchronization error reduction to improve the accuracy of traditional RBS algorithm and meet the requirement of system precision.In order to verify the correctness of synchronization method,an ultra-wideband accurate indoor localization system is designed in this paper,and the hardware and software design of this system is completed.This system consists of tags,anchors and upper computer.Tag is in charge of inquiring the status of synchronization anchor and sending positioning signal,implements the function of multi-tags anti-collision and position detection.Synchronization anchor uses task queue to manage tag positioning and time synchronization,ensures no conflicts between time synchronization and multi-tags positioning.After time synchronization,positioning anchor records the arrival time of positioning signal and calculates its differences,sends the data to host computer.The host computer utilizes the TDOA algorithm to calculate tag position and displays the results on browser.Several measurements such as system synchronization,single-tag positioning,multi-tags anti-collision and positioning have been tested.The results show that this system allows accurate localization under several circumstances,and it can attain high accuracy positioning with 20 cm mean synchronization error,satisfy the requirement of indoor localization and approach the world’s advanced level.