Enhancing the Efficiency of Active RFID-Based Indoor Location Systems

Active RFID-based indoor location systems rely on received signal strength (RSS) measurements in order to report position estimates of target objects. In practice, such systems exhibit a location error in the order of several meters. Much of this is due to the varying-nature of RSS measurements over time. Localization errors of several meters are harmful for applications in which the desired location information is the room or area where the target object is placed. When such location information is wrong, a user searching for the object has no choice other than to perform a blind search through the indoor environment. In this paper, we propose a simple algorithm that can greatly reduce the need for blind searches by automatically reporting to users a second estimate of the possible area in which the target object could be located. We have enhanced the well- known LANDMARC location system with our algorithm for performance evaluation. Simulation results show that the overall location performance is boosted by up to 96.66% in accordance with signal propagation conditions and the placement of target objects.