×

Steerable phase array antenna RFID tag locater and tracking system and methods

  • US 8,742,896 B2
  • Filed: 11/26/2012
  • Issued: 06/03/2014
  • Est. Priority Date: 09/11/2007
  • Status: Active Grant
First Claim
Patent Images

1. A method of locating and tracking an RFID tag, the steps comprising:

  • calibrating at least two phase array steerable antennas to optimally align the antennas with known global coordinates;

    configuring an RFID reader for a working environment;

    performing a two-dimensional raster scan of a visible area of the working environment with a first antenna;

    calculating a minimal covering of the visible area with one or more beam areas;

    defining a set of steering directions for raster scans;

    using the first antenna to determine if one or more RFID tags are present in the beam areas;

    estimating an expected location for at least one RFID tag in the beam area;

    projecting the expected location of the RFID tag into global coordinates;

    estimating the most probable conjugate pairing (“

    PGPt1

    );

    calculating a most likely location of the RFID tag'"'"'s projection in global coordinates relative to a second antenna (“

    PGPt2

    ) using an estimated random distribution of RFID tag heights and PGPt1;

    calculating a projection in global coordinates inverse of PGPt2 so as to yield a most probable steering direction for the second antenna;

    reading with the other antenna in the direction indicated by a plane point projection of PGPt2;

    triangulating any RFID tag seen by the other antenna using PGPt1 and PGPt2;

    triangulating using PGPt1 and PGPt2 if the RFID tag is not seen by the other antenna, as this location is still highly probable as a location for the RFID tag; and

    repeating these steps for each beam area.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×