Radio frequency identification tag location estimation and tracking system and method
First Claim
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.
6 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods for locating one or more radio frequency identification (RFID) tags are provided. A phase difference of received information signals of illuminated RFID tags is utilized to locate the RFID tags. One or more exciters transmit interrogation signals to illuminate the RFID tags in which the exciters may have a plurality of antenna selectively configured to transmit through two or more antennas and to receive on one antenna. Multiple reads of the same RFID tag can also be performed to generate a probability model of the location of the RFID tag. An enhanced particle filter is applied to probability model to determine the exact location of the RFID.
63 Citations
20 Claims
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1. A method of locating one or more radio frequency identification (RFID) tags comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A radio frequency identification (RFID) system for locating one or more RFID tags, the system comprising:
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a plurality of antennas configured to selectively transmit interrogation signals through at least two of the plurality of antennas and to selectively receive information signals from at least one RFID tag through one of the plurality of antennas different from the at least two of the plurality of antennas; and a reader configured to; activate the antennas configured to selectively transmit interrogation signals; determine the path length between the receive antenna, the at least one illuminated RFID tag, and each of the plurality of transmit antennas using the determined group delays of the received information signals; determine a plurality of ellipses based on the locations of each of the plurality of receive antennas, the location of the transmit antenna, and the determined path lengths; and identify a location of the at least one RFID tag based on the determined ellipses. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A method of locating one or more radio frequency identification (RFID) tags comprising:
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illuminating at least one RFID tag by a plurality of transmit antennas using interrogation signals at a plurality of frequencies; receiving a plurality of information signals from the illuminated at least one RFID tag by a receive antenna, where the plurality of information signals include information signals generated in response to interrogation signals sent at different frequencies from each transmit antenna; determining a group delay for each group of received information signals from the at least one illuminated RFID tag received by the receive antenna that were sent in response to interrogation signals from each transmit antenna; determining the path length between the receive antenna, the at least one illuminated RFID tag, and each of the plurality of transmit antennas using the determined group delays of the received information signals; determining a plurality of ellipses based on the locations of each of the plurality of transmit antennas, the location of the receive antenna, and the determined path lengths; and identifying a location of the at least one RFID tag based on the determined ellipses. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification