Feasibility Study of the Unmanned-aerial-vehicle Radio-frequency Identification System for Localizing Construction Materials on Large-scale Open Sites

The locations of construction resources, such as workers, equipment, and materials, are one of the important data types for monitoring the states of ongoing activities. The needs for location data have driven various research efforts on sensing technologies for tracking these resources. Although a GPS has been employed mostly for construction equipment, radio frequency identification (RFID) technology has been used for construction materials including precast elements. The RFID system generally requires an on-site manager to walk around the site holding a reader to communicate with the tags attached to materials at close ranges. These manual procedures are time-consuming and inefficient when the materials are spread over a large-scale broad area. Also, the materials located beyond a manager's reach are undetectable. Therefore, in this study, an unmanned aerial vehicle (UAV)-based system that carries an RFID reader in the air for locating RFID tags attached to materials on the ground is proposed. The proposed UAV-RFID system receives signals from the tags located within the sensing range of the reader and saves their strength indicator values. The candidate area of the tag locations is estimated from the specifications of the reader and the flight altitude. Experimental tests signify that the system has a great potential to replace the manual reading process and improve the material management efficiency.