Preliminary Localization Results With An RFID Based Indoor Guiding System

This paper reports preliminary work with an RFID based local positioning system (LPS) designed for location and guidance of people and autonomous vehicles in indoor environments. The system consists of an RF reader carried by the mobile user, and a number of active RFID tags, disseminated at known positions in the displacement region, which regularly emit RF signals with an identification code. Upon reception of a signal, the range of the user to the corresponding tag is estimated indirectly from the received signal strength (RSSI), using a previously obtained statistical model. A computationally efficient Bayesian localization method (particle filter) is used to process the measurements and produce an estimation of the user's position. The RFID-LPS is tested empirically in a displacement region comprised of three adjacent rooms, with a total area of 250 m2, in which there are placed 21 tags. Our first results show a typical mean positioning error of 3.25 m, which compares favorably with other systems reported in the literature.