Orientation Sensing Using Multiple Passive RFID Tags

Knowing the inclination of an object can be valuable information in a supply chain application, e.g. when handling orientation sensitive objects. In this work we present a method for sensing the inclination using Radio Frequency IDentification (RFID) technology. The method requires standard RFID equipment and assumes that each object is tagged with a passive UHF tag. We use a simple statistical estimator based on the Received Signal Strength (RSS) of the tag reply. The performance is evaluated via experimental measurements, and the results are positive with a good precision within distances of 2 m