Tag Localization by Handheld UHF RFID Reader With Optical and RFID Landmarks

In this paper a prototype method for manual inventorying and real-time 3D localization of RFID tagged products by a low-cost handheld UHF RFID reader is introduced. The device is equipped with a UHF RFID reader and an optical camera. "ArUco" markers with RFID tags are placed at known positions. Those optical and RF landmarks are used for the estimation of the pose of the handheld reader over time, by fusing the corresponding measurements in a Kalman filter. The reader also measures RFID tagged items at unknown locations. The positions of the tags are estimated by unwrapping the collected phase measurements, combined with the estimated antenna trajectory. Experimental results show that increased accuracy can be achieved by increasing the spatial density of the optical and RFID markers. The proposed method is expected to enhance low-cost manual inventorying, delivering 3D localization of the tagged products.