Patent ID: 11914018
Assignee: CORNELL UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A radio-frequency method for range finding, the method comprising:
modulating a reference signal having an intermediate frequency, fIF, to a downlink signal having a carrier frequency, fc, using a clock signal;
transmitting the downlink signal to a tag using a transceiver, the tag being located at a distance from the transceiver;
receiving an uplink signal backscattered from the tag, the uplink signal having a frequency that is a harmonic of the carrier frequency;
demodulating the uplink signal using the clock signal; and
calculating a distance between the tag and the transceiver based on comparing the reference signal to the demodulated uplink signal comprising: determining a difference between a phase of the reference signal and a phase of the demodulated uplink signal, and determining the distance as a linear function of the difference between the phase of the reference signal and the phase of the demodulated uplink signal.