Performance evaluation and verification of spread-spectrum based UHF RFID ranging

Abstract

This paper presents measurement results of a recently introduced time of flight (ToF) ranging method for backscattering RFID tags. The measurements are done with off-the-shelf EPC Class1 Gen2 tags, an automated tag positioner, a modified software defined radio (SDR) platform as the RFID reader, and a PC post-processing the ranging results. The ranging error and its variance is measured and discussed at tag distances of 0.1–4m for different tags, operating frequencies, and ranging signal power levels.