Localization of RFID Tags Through Real-Time Angle-of-Arrival Estimation

Radio frequency identification (RFID) is an enabling technology for many applications of the Internet-of-Things. The most interesting one is its use for localization and tracking purposes. Among all the possible localization techniques, angle-of-arrival (AoA) estimation performed through phase interferometry proved to be accurate and lightweight in terms of complexity, allowing operation in real-time. In this letter, we propose an approach to UHF RFID tag localization by real-time AoA estimation through a dedicated digital architecture. After introducing the idea and its underlying principles, we discuss a preliminary validation campaign using a software-defined radio and a custom RF front-end aiming to demonstrate the accuracy consistency varying the path loss and the signal power levels.