Methods and Systems for Estimating Distance of a Radio Frequency Identification Tag

摘要

A localization method and system, including determining phases of a plurality of response signals at a plurality of frequencies received from a radio frequency identification (RFID) tag in response to interrogation signals by a reader at the plurality of frequencies; calculating a first distance estimate of a distance between the RFID tag and the reader based on a signal strength measured from a first response signal of the plurality of response signals; based on the phases and the first distance estimate, calculating a phase slope; and determining a second distance estimate of the distance based upon the phase slope.

主权项

1. A method for determining a distance between a radio frequency identification (RFID) tag and a reader, comprising:
transmitting, by the reader, a plurality of interrogation signals to the RFID tag at a plurality of frequencies; receiving, by the reader, a plurality of response signals from the RFID tag in response to the plurality of interrogation signals; determining a phase of each of the received plurality of response signals, and a first distance estimate of the distance based on a signal strength measured from a first response signal of the plurality of response signals; based upon the first distance estimate, altering one or more of the phases to achieve a phase trend of the phases; calculating a phase slope associated with the phase trend; and determining a second distance estimate of the distance based upon the phase slope.