Indoor Localization System Based on Passive RFID Tags

In this paper, we present a low-cost localization system using UHF RFID passive tags in indoor environments. It can be used to locate objects or people in an unfamiliar building. The signal power distribution, propagation conditions and environmental factors will be studied in more detail. Landmark reference tag grid is applied in our system. The tag RSSI (Received Signal Strength Indication) is the main value for our improved K nearest neighbor algorithm. Path Loss models for an indoor environment are also analyzed. The error map and the accuracy of the reference positions are constructed through the Path Loss model for helping to choose corresponding K reference positions.