Cooperative Multi‐tag Localization in RFID Systems: Exploiting Multiplicity, Diversity and Polarization of Tags

Radio frequency identification (RFID) positioning systems can entail either tag localization or reader localization. This chapter first presents a tag localization system with multiple tags attached to the target and a data fusion algorithm combining measurements obtained at reference readers from the multiple tags. It then presents a reader localization system with a single antenna reader carried by the target and angle of arrival (AOA) measurements obtained from reference tag‐pairs. In order to increase the localization accuracy, multiple tags can be deployed on a target. With respect to a single‐tag system, a multi‐tag system has several advantages: multiple/redundant data availability per instance, faster retrieval of statistics per target, higher robustness and quality of service (QoS). Moreover, a multi‐tag system has a higher likelihood of line of sight (LOS) as well as a lower likelihood of polarization mismatches between the tags and the reader, which implies a higher number of correct readings.