Research On Relative Positioning Algorithm Based On UHFRFID

With the development of information technology,context-aware services based on location information have attracted more and more attention.Radio Frequency Identification(RFID)technology has been developed and applied to logistics management,library management,passenger flow analysis,and manufacturing industries with its advantages of non-line-of-sight,low cost,and easy expansion.Although a lot of research on RFID positioning technology,there are still some problems that have not been solved properly.In indoor navigation,logistics monitoring and other scenarios,managers are more concerned with the relative location information of the target than the absolute location information.Most absolute positioning algorithms are difficult to achieve centimeter-level positioning accuracy,hence,their performance cannot meet the requirements of relative positioning.Quite a few absolute positioning algorithms could obtain lower positioning errors,however,their establishment and implement rely on dedicated hardware devices,which narrows the application fields.This paper studies the relative positioning problems based on the Received Signal Strength Indicator(RSSI).Firstly,a high-precision UHF RFID channel model for mobile scenes is proposed to extract tag identity information and signal profile.Secondly,a multi-reference power profile relative location algorithm based on dynamic time warping technology is proposed.Multi-point equalization mechanism is introduced to improve the accuracy of local position.The simulation results show that the proposed method has higher accuracy than the G-RSSI algorithm and the RSSI algorithm based on STPP.Finally,a relative localization algorithm suitable for uncertain radiation scene is proposed.The higher order fitting mechanism is leveraged to smooth the uncertain profile used as positioning basis.According to the difference of similarity between different tag positions,the concept of central reference is proposed to improve the selection of reference position in the relative positioning algorithm.The experimental results show that,compared with G-RSSI and FCFS algorithm,the proposed method can achieve better positioning performance.