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:
- transmitting, to at least one RFID tag, a first interrogation signal from a first transmit antenna at a first location and a different second interrogation signal from a second transmit antenna at a second location;
receiving first and second information signals at a set of one or more receive antennas in a third location in response to the first and second interrogation signals from the at least one RFID tag;
determining a set of phase differences for the received first and second information signals from the at least one RFID tag received by the at least one receive antenna;
determining, based on the set of phase differences;
a first path length between the first location of the first transmit antenna, the at least one RFID tag, and the third location of the set of receive antennas, anda second path length between the second location of the second transmit antenna, the at least one RFID tag, and the third location of the set of receive antennas; and
identifying a location of the at least one RFID tag based on the determined phase differences of the first and second received information signals and the first and second path lengths.
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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.
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Citations
19 Claims
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1. A method of locating one or more radio frequency identification (RFID) tags comprising:
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transmitting, to at least one RFID tag, a first interrogation signal from a first transmit antenna at a first location and a different second interrogation signal from a second transmit antenna at a second location; receiving first and second information signals at a set of one or more receive antennas in a third location in response to the first and second interrogation signals from the at least one RFID tag; determining a set of phase differences for the received first and second information signals from the at least one RFID tag received by the at least one receive antenna; determining, based on the set of phase differences; a first path length between the first location of the first transmit antenna, the at least one RFID tag, and the third location of the set of receive antennas, and a second path length between the second location of the second transmit antenna, the at least one RFID tag, and the third location of the set of receive antennas; and identifying a location of the at least one RFID tag based on the determined phase differences of the first and second received information signals and the first and second path lengths. - View Dependent Claims (14, 15, 16)
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2. A radio frequency identification (RFID) system for locating one or more RFID tags, the system comprising:
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a plurality of antennas comprising; first and second transmit antennas configured to transmit interrogation signals to at least one RFID tag, wherein the first and second transmit antennas are at first and second locations respectively; and at least one receive antenna to receive information signals from the at least one RFID tag; and a reader configured to; selectively activate the first transmit antenna to transmit a first interrogation signal at a first frequency and the second transmit antenna to transmit a second interrogation signal at a different second frequency; receive first and second information signals in response to the first and second interrogation signals at a set of one or more receive antennas in a third location; and identify a location of the at least one RFID tag based on the first, second, and third locations, and a first path length between the set of receive antennas, the at least one RFID tag, and the first transmit antenna, and a second path length between the set of receive antennas, the at least one RFID tag, and the second transmit antenna, wherein the path lengths are determined from the first and second information signals. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 17, 18, 19)
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Specification