The area of passive UHF RFID is mostly a niche application for tracking of small goods. Accurate localization of tagged objects could be beneficial in numerous applications, such as warehouse and point-of-sale portals, salesrooms, or archives. Although there has been considerable research on this issue since 2005, accurate positioning remains elusive. There are two major reasons for this: Severe multipath propagation due to the backscatter nature (degenerate channels) and the portal setup (resembling industrial environments) is the dominant source of errors. In combination with limitations enforced by the design of passive UHF RFID (low-power, low-complexity tags; high throughput of tags in portals), this makes ranging in passive UHF RFID a very challenging task.

The question treated and answered by this project is: “Is it possible to determine the position of a passive UHF RFID tag given a set of readers at known positions and within the limitations of passive UHF RFID? If so, how?”