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 (IoT). 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 (SDR) and a custom RF front-end aiming to demonstrate the accuracy consistency varying the path loss and the signal power levels.