A Real-Time RFID Positioning System Using Tunneling Tags

This paper proposes a new type of real-time decimeter-level radio-frequency identification (RFID) positioning system at 5.8 GHz. The system uses received signal phase (RSP)-based positioning techniques and tunneling tags (TTs). TTs amplify the signal strength of their backscattered signals while preserving the phases allowing for ultra-precise position estimates at long distances. A proof-of-concept RSP-based real-time frequency hopping reader is implemented on Software-Defined Radio (SDR) and Universal Software Radio Peripheral (USRP) platform. Experimental results show an average one dimensional and two-dimensional positioning accuracy of 11 cm and 17 cm, respectively, in outdoor environments.