A novel approach of RFID based indoor localization using fingerprinting techniques

In this paper, a novel approach for an indoor localization using a fingerprint technique is proposed. The UHF band Radio Frequency Identification (RFID) system is utilized. The passive RFID tags are employed as references attached to the ceiling at known locations and the RFID reader carrying on the vehicle of interest is the target to be localized. The basic principle of the fingerprint technique is to find the location of the target by comparing its signal (or information) pattern with a previously recoded database of known signal (or information)-location data. Therefore, there are two main steps to estimate the target location: (i) construction of database containing the signals (or information) and their corresponding locations, and (ii) estimation of the target location. In this paper, firstly, the detected tags found by the reader at each location of interest are collected and from now on the detected tags are called a fingerprint. Secondly, the location of the reader can be estimated using two proposed methods using the intersection between the detected tags and fingerprints. These two methods are compared to a simple method called the center of gravity (C.G.). The effectiveness of this method is verified by an indoor experiment. The result of location estimation error is less than 60 cm.