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Radio frequency identification tag location estimation and tracking system and method

  • US 10,585,159 B2
  • Filed: 02/09/2018
  • Issued: 03/10/2020
  • Est. Priority Date: 04/14/2008
  • Status: Active Grant
First Claim
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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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