Accurate indoor position estimation by Swift-Communication Range Recognition (S-CRR) method in passive RFID systems

RFID (Radio Frequency IDentification) systems have become meaningful as a new identification source that is applicable in ubiquitous environments. Each RFID tag has a unique ID, and is attached to some object. A user reads the unique ID of a RFID tag with RFID readers and obtains the information on the object. One of the important technologies that use the RFID systems is the indoor position estimation of RFID readers. If a user can understand a position of an RFID reader, the position estimation can be applied to a navigation system for walkers. Using conventional methods, the system needs more than two RFID tags for the accurate indoor position estimation, and the accuracy itself of position estimation is not so high. In this paper, we propose a new method for accurate indoor position estimation of passive RFID systems. In this method, the position of an RFID reader is estimated using SCRR (Swift Communication Range Recognition) method. The proposed method is capable of accurate position estimation in near real time regardless for large numbers of RFID tags.