Patent ID: 9291699
Filing Date: 2016-03-22
CPC Classification: G01S,G06K

Claim Text:
1. A method of locating one or more radio frequency identification (RFID) tags comprising: illuminating at least one RFID tag by an exciter using a plurality of frequencies; receiving information signals from the illuminated at least one RFID tag by a plurality of receive antennas; determining a group delay for the received information signals from the at least one illuminated RFID tag received by each of the plurality of receive antennas; determining the path length between the exciter, the at least one illuminated RFID tag, and each of the plurality of receive antennas using the determined group delay of the received information signals at each of the plurality of receive antennas: determining a plurality of ellipses based on the locations of each of the plurality of receive antennas, the location of the exciter, and the determined path lengths; and identifying a location of the at least one RFID tag based on the determined ellipses.