Range measuring method, range measuring apparatus, non-contacted IC medium and range measuring system

• US 8,149,155 B2
• Filed: 12/18/2008
• Issued: 04/03/2012
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Kawai, Takehiro
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US12/338,538
• Publication Number:
  US 20090195438A1
• Time in Patent Office: 1,202 Days
• Field of Search: 342 42- 51, 342/118, 342/127, 340 103- 106, 455/21
• US Class Current: 342/42
• CPC Class Codes: G01S 13/84 for distance determination by phase measurement

Abstract

A method of measuring a range from a reader unit to a non-contacted IC medium, includes: transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium; causing the non-contacted IC medium to perform modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency, and causing the non-contacted IC medium to respond to a response signal at the modulated frequency; causing the reader unit to receive the response signal to acquire a plurality of frequency components; calculating a phase difference between signals of at least two of the acquired plurality of frequency components; and measuring the range by using the phase difference.

Claims

1. A method of measuring a range from a reader unit to a non-contacted IC medium, the method comprising:

transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium;

causing the non-contacted IC medium to perform modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency, and causing the non-contacted IC medium to respond to the inquiry signal with a response signal at the modulated frequency, the response signal comprising an upper side band (USB) signal component and a lower side band (LSB) signal component;

causing the reader unit to receive the response signal to acquire a plurality of frequency components by extracting I and Q components from the response signal;

calculating from the extracted I and Q components a phase difference between the upper side band (USB) signal component and the lower side band (LSB) signal component; and

measuring the range by using the calculated phase difference.

2. The method according to claim 1, wherein phase shift keying is used for the modulation.

3. The method according to claim 1, wherein frequency shift keying is used for the modulation.

4. The method according to claim 1, wherein

the modulation is digital modulation, and

the plurality of frequency components are high frequency components generated in the digital modulation.

5. The method according to claim 1, wherein the response signal is separated into the upper side band signal component and the lower side band signal component in order to acquire the plurality of frequency components.

6. The method according to claim 1, further comprising:

combining the range with an ID included in the response signal to create an ID-range; and

outputting the ID-range.

7. The method of claim 1, wherein the first frequency comprises a single frequency.

8. The method of claim 1, wherein the inquiry signal comprises a modulation system code for designating a modulation system and the non-contacted IC medium comprises a plurality of modulation circuits corresponding to a plurality of modulation systems, respectively, and is configured to select one of the modulation circuits corresponding to the modulation system designated by the modulation system code for use in said modulation performed by the non-contacted IC medium.

9. An apparatus, operable to measure a range from a reader unit to a non-contacted IC medium, the apparatus comprising:

a communication unit for transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium and for receiving a response signal from the non-contacted IC medium, the response signal being generated by modulating the first frequency of the inquiry signal and comprising an upper side band (USB) signal component and a lower side band (LSB) signal component;

a frequency component acquiring unit for acquiring the plurality of frequency components from the received response signal by extracting I and Q components from the response signal; and

a range measuring unit for calculating from the extracted I and Q components a phase difference between the upper side band (USB) signal component and the lower side band (LSB) signal component, and measuring the range by using the calculated phase difference.

10. A non-contact IC medium, comprising:

a communication unit for receiving an inquiry signal at a first frequency from a reader unit and for responding to the inquiry signal with a response signal to the reader unit, the response signal comprising an upper side band (USB) signal component and a lower side band (LSB) signal component;

a modulation unit far performing modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency; and

a plurality of modulation circuits corresponding to a plurality of modulation systems, respectively,

wherein the communication unit responds to the inquiry signal with the response signal at the modulated frequency, and the response signal is generated by one of a selected one of said modulation circuits and has a plurality of frequency components that enable the reader unit to measure the range from the reader unit to the non-contact IC medium, and

wherein the non-contact IC medium sends the response signal having a plurality of frequency components to the reader unit thereby enabling the reader unit to extract I and Q components from the response signal, calculate from the extracted I and Q components a phase difference between the upper side band (USB) signal component and the lower side band (LSB) signal component and measure the range from the reader unit to the non-contact IC medium using the calculated phase difference.

11. A range measuring system, comprising:

a non-contacted IC medium; and

a range measuring apparatus operable to measure a range from a reader unit to the non-contacted IC medium, the apparatus comprising;

a first communication unit for transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium and for receiving a response signal from the non-contacted IC medium, the response signal comprising an upper side band (USB) signal component and a lower side band (LSB) signal component;

a frequency component acquiring unit for acquiring a plurality of frequency components from the received response signal by extracting I and Q components from the response signal; and

a range measuring unit for calculating from the extracted I and Q components a phase difference between the upper side band (USB) signal component and the lower side band (LSB) signal component and measuring the range by using the calculated phase difference,

wherein the non-contacted IC medium comprises;

a second communication unit for receiving the inquiry signal at the first frequency from the reader unit, and responding to the inquiry signal with a response signal to the reader unit;

a modulation unit for performing modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency; and

a plurality of modulation circuits corresponding to a plurality of modulation systems, respectively,

and

wherein the second communication unit responds to the inquiry signal with the response signal at the modulated frequency, and generated by a selected one of said modulation circuits.