Research Of Positioning Algorithm For RFID Tags Based On Unwrapping Phase

In the warehousing and logistics industry,efficient positioning technology can improve the system's intelligence level and management efficiency.It is an enabling technology for building intelligent warehouse logistics systems.The existing RFID positioning technology uses the arrival time,received signal strength,arrival direction angle and other information to achieve positioning,and has the disadvantages of low positioning accuracy and poor real-time performance.This thesis proposes an RFID tag location algorithm based on unwrapping phase,which has the advantages of high positioning accuracy,strong anti-interference,and good real-time performance.The main research content of this thesis includes:An RFID tag location algorithm based on phase-distance model is proposed,and on this basis,a mobile dual antenna positioning system is constructed.For the problem of discontinuity in the wrapping phase-distance model,An RFID tag location algorithm based on the unwrapping phase-distance model is proposed.Based on this algorithm,a mobile dual-antenna RFID tag positioning system combining the RFID system and the robot system is constructed.For the phase-unwrapping problem in phase-based RFID tag positioning system,based on traditional phase unwrapping algorithm,a phase unwrapping algorithm based on shooting method is proposed,which can not only solve the problem of ? phase hopping,2? cycle ambiguity problem,but also can effectively solve the problem of phase loss,improve the robustness of RFID tag positioning system.The positioning error of the mobile dual-antenna positioning system is analyzed.The precision factor of the mobile dual-antenna positioning system is deduced based on the precision factor theory.The influence of the system parameters of the dual-antenna positioning system on the positioning error is analyzed,and based on the analysis conclusions,the optimization measures of the system parameters are proposed.A mobile dual-antenna positioning system is developed with the Pioneer-3 DX mobile robot.Experiments of the phase unwrapping algorithm based on the shooting method are designed and carried out with this system,and the effectiveness of the algorithm is proved.Experiments of the systematic error analysis of the factor are designed and carried out,which proves the effect of the optimized selection of system parameters on the positioning accuracy of the system.Experiments of the RFID tag positioning algorithm based on the unwrapping phase are conducted,and the positioning accuracy of the system is analyzed.The accuracy,efficiency of this positioning algorithm are verified.