Simultaneous 2D Localization of Multiple Standard Passive LF-RFID Transponders

In this paper, an approach to the simultaneous two dimensional localization of 16 LF-RFID transponders is proposed. The underlying hardware setup as well as the localization algorithms are explained. Prior to the localization, the transponders must be programmed with a special modulation pattern. A detailed discussion on the modulation pattern and the synchronization of the signals is given. The advantage of the proposed method is that no complex bi-directional communication protocol or anti-collision method needs to be employed. The theoretical amount of simultaneously localizable transponders is limited to 64 by the size of the transponder memory. Using a laboratory setup consisting of a wooden shelf with 16 compartments, the localization and identification method is demonstrated with 16 transponders. Limitations of the method are pointed out and probabilities of failures are measured. The robustness of the method is shown with metallic components being added to the shelf.