Distance measuring apparatus, distance measuring method, reflector, and communication system
AssigneeOMRON Corporation
InventorsHideyuki Ohara, Takehiro Kawai, Keisuke Saito, Kosuke Hayama
Life of this patent
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Abstract
A transmission controller 7B is configured to transmit an R/W request signal for requesting transmission of a tag response signal to a RFID tag 1 twice. At this time, a frequency controller 7A controls a PLL section 5A to transmit the R/W request signal via different carrier frequencies. A phase information acquirer 8A detects a phase change amount of the tag response signal that is transmitted via different carrier frequencies. A distance calculator 8B calculates the distance between the reader/writer 2 and the RFID tag 1 on the basis of the phase change amount.
Claims15
1-27. (canceled)
A distance measuring apparatus, comprising:
- a transmitter, configured to transmit first one-frame signals from an antenna via radio waves having three or more different carrier frequencies, each of the first one-frame signals being composed of a request signal and a continuous carrier wave;
- a receiver, configured to receive second one-frame signals generated when the first one-frame signals are reflected by a reflector while being modulated, each of the second one-frame signals having a frequency corresponding to a frequency of an associated one of the first one-frame signals;
- a phase information acquirer, configured to calculate a phase change amount between the first one-frame signals and the second one-frame signals for each of the carrier frequencies;
- and
- a distance calculator, configured to calculate a distance between the antenna and the reflector by high-resolution spectrum analysis, on the basis of the carrier frequencies and the phase change amount calculated for each of the carrier frequencies.
A distance measuring method, comprising:
- transmitting first one-frame signals from an antenna via radio waves having three or more different carrier frequencies, each of the first one-frame signals being composed of a request signal and a continuous carrier wave;
- receiving second one-frame signals generated when the first one-frame signals are reflected by a reflector while being modulated, each of the second one-frame signals having a frequency corresponding to a frequency of an associated one of the first one-frame signals;
- calculating a phase change amount between the first one-frame signals and the second one-frame signals for each of the carrier frequencies;
- and
- calculating a distance between the antenna and the reflector by high-resolution spectrum analysis, on the basis of the carrier frequencies and the phase change amount calculated for each of the carrier frequencies.
Dependencies are inferred from the claim text.