Localization of passive UHF RFID Labels with Kalman Filter

[摘要] Localization via Radio Frequency Identification (RFID) is frequently used indifferent applications nowadays. It has the advantage that next to itsostensible purpose of identifying objects via their unique IDs it cansimultaneously be used for the localization of these objects. In this work itis shown how Received Signal Strength Indicator (RSSI) measurements atdifferent antennae of a passive UHF RFID label can be combined forlocalization. The localization is only done based on the RSSI measurementsand a Kalman Filter (KF). Because of non-linearities in the measurementfunction it is necessary to incorporate an Extended Kalman Filter (EKF) or anUnscented Kalman Filter (UKF) where simulations have shown that the UKFperforms better than the EKF. Additionally to the selection of the filterthere are different possibilities to increase the localization accuracy ofthe UKF: The advantages of using Reference Tags (RT) or more than one tag pertrolley (relative positioning) in combination with an Unscented Kalman Filterare discussed and simulations results show that the localization error can bedecreased significantly via these methods. Another possibility to increasethe localization accuracy and in addition to achieve a more realisticsimulation is the consideration of the angle between reader antenna and tag.Simulation results with the incorporation of different numbers of fixedantennae lead to the conclusion that this is a useful surplus in thelocalization.

[学科分类] 电子、光学、磁材料