Method, system and computer program product for ranging RFID tags

摘要

The invention relates to a method for ranging a radio frequency tag, comprising measuring the modulated backscattering response of the tag at a plurality of frequencies using reader and determining the dispersive properties of the tag from the amplitude of the measured backscattering response. Further, the method comprises determining a position parameter of the tag from the measured modulated backscattering response and the determined dispersive properties of the tag.

主权项

1. A method for ranging a radio frequency tag, comprising
measuring modulated backscattering response of the tag at a plurality of frequencies using a reader, and determining at least one position parameter of the tag using the measured modulated backscattering response of the tag using Fourier transform, wherein said position parameter is a distance between the tag and the reader, wherein the position parameter is determined usingmaxz⁢{|∫Δ⁢⁢Ymeas⁡(ω)ΔΓest⁡(ω)⁢ⅇj⁢2⁢ωc⁢z⁢ⅆω|}, wherein ΔYmeas(ω) is a measured difference signal between two reflection; states of the tag corresponding to two backscattering reflection coefficients, ΔΓest(ω) is a modulated reflection coefficient of the tag, and ω is angular frequency of the modulated backscattering response of the tag,wherein the method comprises
measuring said modulated backscattering response at each of said plurality of frequencies using a power which is at maximum 3 dB higher than a threshold power of the tag or more than 3 dB higher than the threshold power of the tag, wherein the modulated reflection coefficient of the tag is estimated using the modulated backscattering response.