US 2021/0199747 A1 · METHODS AND APPARATUS FOR LOCATING RFID TAGS

Abstract

A radio frequency identification (RFID) system includes an array of antennas to distinguish line-of-sight (LOS) paths from non-line-of-sight (NLOS) paths. The distance between adjacent antennas in the array of antennas is less than half the wavelength of the radio frequency (RF) signal of the system. Each antenna in the antenna array is also digitally controlled to change relative phase difference among the antennas, thereby allowing digital steering of the array of antennas across angles of arrival (AOAs) between 0 and 71 The digital steering generates a plot of signal amplitudes as a function of AOAs. LOS paths are distinguished from NLOS paths based on the shapes (e.g., depth, gradient, etc.) of local extremes (e.g., maxima or minima) in the plot.

Claims40

Dependent claims

A method of calibrating a radio-frequency identification (RFID) tag location system comprising a plurality of antennas operably coupled to a processor, the method comprising:

for each of a plurality of reference RFID tags, measuring, with the plurality of antennas, a reference signature representing radio-frequency (RF) power received from the reference RFID tag to the plurality of antennas, each reference RFID tag being at a known location;
measuring, with the plurality of antennas, a signature representing RF power received from an RFID tag at an unknown location to the plurality of antennas;
performing a comparison of the signature to the reference signatures;
and
determining, based on the comparison, an estimated position of the RFID tag relative to the known location of at least one of reference RFID tag in the plurality of RFID tags.

2 more elements

Dependencies are inferred from the claim text.

Methods and apparatus for locating rfid tags

Life of this patent

Methods and apparatus for locating rfid tags

Life of this patent

Abstract

Claims40