Patent ID: 7693681

Claim:
A method for determining a three-dimensional position of a Radio Frequency Identification (RFID) tag, comprising the steps of: moving, by a controller, a mobile object carrying an RFID antenna in a workplace to a first position where the RFID antenna receives a radio signal from said RFID tag; determining, by the controller, horizontal angle from the RFID antenna to the RFID tag based on the feasibility of communication between the RFID antenna and the RFID tag as the RFID antenna is turned or moved in a horizontal direction at the first position by the controller; determining, by the controller, a vertical angle from the RFID antenna to the RFID tag based on the feasibility of communication between the RFID antenna and the RFID tag as the RFID antenna is turned or moved in a vertical direction by the controller; determining, by the controller, a distance from the RFID antenna to the RFID tag based on the power of the signal received from the RFID tag; and determining, by the controller, a three-dimensional position of the RFID tag by vector calculation using the horizontal angle, the vertical angle, and the distance.