Mobile Robot Localization using Rotating Synthetic Aperture RFID

Wireless location sensing plays a critical role in the developing Internet of Things (IoT), which has been attracting increasing attention in both the academia and industry recently. Nowadays UHF Radio Frequency Identification (RFID), due to its long-range, inexpensive, multi-tag identification and battery-free sensing capability, has been widely applied for localization especially in intelligent manufacturing factories and warehouses. Inspired by the robustness against noise and multipath distortion of synthetic aperture radar, we present a rotating synthetic aperture RFID method for robot localization in this paper. Based on this method, a robot equipped with a rotating RFID antenna perceives the position of itself, so it is a smart transporter unit in manufacturing for searching and conveying objects. The robot estimates its positions based on synthetic aperture RFID with an indistinct trajectory. Rotation and multi-frequency technique improves the resolution and location accuracy. The theoretical ambiguity analysis is also proposed. We evaluate the performance with commercial-off-the-shelf (COTS) RFID devices and build a prototype system with cm-level mean accuracy.