US 11,914,018 B2
System and method for ultra-high-resolution ranging using RFID
Xiaonan Hui, Ithaca, NY (US); and Edwin C. Kan, Ithaca, NY (US)
Assigned to Cornell University, Ithaca, NY (US)
Filed by Cornell University, Ithaca, NY (US)
Filed on Aug. 31, 2022, as Appl. No. 17/900,480.
Application 17/900,480 is a continuation of application No. 17/289,702, granted, now 11,519,996, previously published as PCT/US2019/059274, filed on Oct. 31, 2019.
Claims priority of provisional application 62/753,845, filed on Oct. 31, 2018.
Prior Publication US 2022/0413082 A1, Dec. 29, 2022
Int. Cl. G01S 1/30 (2006.01); G01S 1/04 (2006.01); G01S 1/02 (2010.01); G01S 13/84 (2006.01); G01S 13/75 (2006.01)
CPC G01S 1/306 (2013.01) [G01S 1/022 (2013.01); G01S 1/0428 (2019.08); G01S 13/84 (2013.01); G01S 13/751 (2013.01)] 19 Claims
OG exemplary drawing
 
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.