System and method for distance measurement

• US 7,209,071 B1
• Filed: 05/07/2004
• Issued: 04/24/2007
• Est. Priority Date: 05/07/2004
• Status: Expired due to Fees

• Current Assignee: Steele Boring
• Original Assignee: Steele Boring
• Inventors: Boring, Steele
• Primary Examiner(s): Gregory; Bernarr E.
• Application Number:
  US10/840,353
• Time in Patent Office: 1,082 Days
• Field of Search: 342 29- 51, 342/118, 342/125, 342/175, 342/195, 342/385, 342/386, 342399-406, 342192-197
• US Class Current: 342/42
• CPC Class Codes: G01S 13/40 wherein the frequency of transmitted signal is adjusted to give a predetermined phase relationship
• CPC Class Codes: G01S 13/82 wherein continuous-type signals are transmitted

Abstract

A system and method for performing distance measurement using wireless signals. A time of flight calculation is enabled by an interrogating device that transmits an interrogation signal to a responding device, which returns a synchronized signal back to the interrogating device. The wireless signals between the interrogating device and the receiving device have a harmonic relationship. In one embodiment, a time shift of a received signal relative to a transmitted interrogation signal is determined based on a comparison of a first reference point on a signal representative of the transmitted interrogation signal and a second reference point on a signal representative of the received signal.

Claims

1. A method for measuring distance between an interrogating device and a responding device, comprising:

transmitting from an interrogating device an interrogation signal at a first frequency;

receiving a signal from a responding device in response to said interrogation signal, said received signal having a second frequency that is a harmonic of said first frequency;

determining a time shift of said received signal relative to said transmitted interrogation signal, said determined time shift being based on a comparison of a first reference point on a signal representative of said transmitted interrogation signal and a second reference point on a signal representative of said received signal; and

determining a distance between the interrogating device and the responding device using said determined time shift.

2. The method of claim 1, wherein said interrogation signal and said received signal include periodic reference pulses.

3. The method of claim 1, wherein one of said first reference point and said second reference point is a signal peak or zero crossing.

4. The method of claim 1, wherein said first reference point is on a periodic reference pulse.

5. The method of claim 1, wherein said determining a distance comprises multiplying said determined time shift by the speed of light.

6. The method of claim 1, wherein said determining a time shift comprises comparing a signal representative of said received signal to a phase-shifted version of a signal representative of said transmitted interrogation signal.

7. The method of claim 1, wherein said determining a time shift comprises comparing a signal representative of said received signal to a phase-shifted version of a harmonic of said transmitted signal.

8. The method of claim 1, wherein said determining a time shift comprises determining an interference measure.

9. The method of claim 1, wherein said determining a time shift comprises phase-tuning a signal representative of said transmitted interrogation signal to a signal representative of said received signal.

10. The method of claim 1, wherein said determining a time shift comprises comparing a signal representative of said received signal to a harmonic of said transmitted signal.

11. A method for measuring distance between an interrogating device and a responding device, comprising:

receiving from an interrogating device an interrogation signal at a first frequency;

selecting a second frequency that is a harmonic of said first frequency; and

transmitting a signal in response to said interrogation signal, said transmitted signal having said second frequency and having a first reference point that is aligned with a second reference point in said received interrogation signal.

12. The method of claim 11, wherein said received interrogation signal includes periodic reference pulses.

13. A system for measuring distance between an interrogating device and a responding device, comprising:

a transmitter that is configured to transmit an interrogation signal at a first frequency;

a receiver that is configured to receive a signal from a responding device in response to said interrogation signal, said received signal having a second frequency that is a harmonic of said first frequency;

a processing system that is configured to determine a time shift of said received signal relative to said transmitted interrogation signal, said determined time shift being based on a comparison of a first reference point on a signal representative of said transmitted interrogation signal and a second reference point on a signal representative of said received signal, and to determine a distance between the interrogating device and the responding device using said determined time shift.

14. The system of claim 13, wherein said interrogation signal and said received include periodic reference pulses.

15. The system of claim 13, wherein one of said first reference point and said second reference point is a signal peak or a zero crossing.

16. The system of claim 13, wherein said first reference point is on a periodic reference pulse.

17. The system of claim 13, wherein said processor multiplies said determined time shift by the speed of light.

18. The system of claim 13, wherein said processing system includes a signal analysis component that is configured to compare a signal representative of said received signal to a phase-shifted version of a harmonic of said transmitted signal.

19. The system of claim 13, wherein said processing system includes a signal analysis component that is configured to compare a signal representative of said received signal to a harmonic of said transmitted signal.

20. The system of claim 13, wherein said determined time shift is based on an interference measure.

21. The system of claim 13, wherein said processing system includes a signal analysis component that phase-tunes a signal representative of said transmitted interrogation signal to a signal representative of said received signal.

22. A system for measuring distance between an interrogating device and a responding device, comprising:

a receiver that is configured to receive an interrogation signal at a first frequency;

a processor that is configured to select a second frequency that is a harmonic of said first frequency; and

a transmitter that is configured to transmit a signal in response to said interrogation signal, said transmitted signal having said second frequency and having a first reference point that is aligned with a second reference point in said received interrogation signal.

23. The system of claim 22, wherein said received interrogation signal includes periodic reference pulses.