Localization of UHF RFID labels with reference tags and Unscented Kalman Filter

To accomplish location-awareness in indoor scenarios Radio Frequency Identification (RFID) tags are often used for the localization. This paper only uses Received Signal Strength Indicator (RSSI) values from passive UHF RFID labels for the localization process. The RSSI values of reference tags (RTs) for which the locations are known are employed as side information for the localization of an RFID label (LT). For the localization of this LT an Unscented Kalman Filter (UKF) in combination with the RTs information is used. Simulations based on measured data achieve a localization accuracy of about 17cm with this localization method, compared to a localization error of 20cm without RTs and 83cm when only using k nearest neighbor (kNN) algorithm.