Passive UHF RFID tag localization using reader antenna spatial diversity

A simple and robust RSSI based passive RFID localization technique has been investigated. The algorithm does not depend on the type of RFID tags or orientation, and is independent of the environment as long as there is a reasonable line of sight between the reader antennas and the interrogation zone. Experimental results show that the average estimated distance error is 17cm for a single tag in an open space, and 48cm for an area cluttered with many retail items. Our future work will focus on using phase information combined with RSSI to enhance the localization accuracy. Improved propagation models and positioning algorithms will be developed for robust estimation under varying environmental conditions.