Indoor Localization Technology Research Based On Multidimensional Scaling For Passive UHF RFID

In recent years,passive ultrahigh-frequency(UHF)RFID tag localization has been increasingly concerned.However,due to the multipath propagation in the indoor environment,the positioning accuracy of traditional location algorithms significantly declines.In order to improve the positioning accuracy in the complicated indoor environment,the algorithms based on multidimensional scaling for passive UHF RFID are researched in the paper.Based on the research of passive UHF RFID,the passive UHF RFID multipath channel model and the ranging error model are proposed,laying the foundation for the algorithm research.To improve the localization accuracy in multipath channel,the traditional algorithms are researched and a robust algorithm named residual weighted multidimensional scaling(RWMDS)is proposed.In order to construct the squared distance and scalar conduct matrix in the RWMDS algorithm,the reader-to-tag and the tag-to-tag distances are required.The inter-tag distances are estimated using a few reference tags by establishing the relationship between inter-tag distance and phase information vectors measurement.Based on the modeling of ranging error in multipath environment,the RWMDS algorithm can be applied to determine the estimated locations of the tags through a few iterations.Simulation results show that the RWMDS algorithm achieves higher localization accuracy than traditional algorithms in multipath environment.