System and method for distance measurement by inphase and quadrature signals in a radio system

• US 6,922,166 B2
• Filed: 01/05/2004
• Issued: 07/26/2005
• Est. Priority Date: 05/26/1998
• Status: Expired due to Term

• Current Assignee: Humatics Corporation
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Richards, James L., Fullerton, Larry W., Meigs, David C., Cowie, Ivan A., Stanley, Randall S.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US10/750,897
• Publication Number:
  US 20040135719A1
• Time in Patent Office: 568 Days
• Field of Search: 342 52- 58, 342 27- 32, 342/134, 342/135, 342/118, 342/125, 342/175, 342/194, 342/195, 342/450, 342/458, 342/463, 342/464, 342/465, 356/4.01, 356/5.01, 356/5.05, 356/5.08, 356/5.09
• US Class Current: 342/125
• CPC Class Codes: G01S 13/08 Systems for measuring distance only indirect measurement G01S13/46
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/913 for landing purposes

Abstract

A system and a method for distance measurement utilizes a radio system. The distance is measured in coarse resolution, and in fine resolution that corresponds to distance attributes. The distance between first and second radio transceivers is determined from the coarse distance and the fine distance attributes.

Claims

1. A method for distance measurement using a radio system, comprising:

measuring a coarse distance between a first radio transceiver and a second radio transceiver, the coarse distance representing a first distance measurement between the first radio transceiver and the second radio transceiver in coarse resolution;

measuring a fine distance between the first radio transceiver and the second radio transceiver, the fine distance representing a second distance measurement between the first radio transceiver and the second radio transceiver in fine resolution,

determining the distance between the first radio transceiver and the second radio transceiver using the first distance measurement in conjunction with the second distance measurement.

2. The method for distance measurement of claim 1, further comprising:

generating a transmit timing signal;

generating a receive timing signal; and

generating a time delay signal based on the transmit timing signal and the receive timing signal; and

wherein the first distance measurement is determined using the time delay signal.

3. The method for distance measurement of claim 2, further comprising:

generating a first timing signal, TX(I), using the transmit timing signal;

generating a second timing signal, RX, using the receive timing signal; and

generating a third timing signal, TX(Q), using at least one of the transmit timing signal and TX(I).

4. The method for distance measurement of claim 3, further comprising:

generating an in-phase (I) signal using the TX(I) and RX signals; and

generating a quadrature (Q) signal using the TX(Q) and RX signals,

wherein the second distance measurement is determined using the in-phase (I) signal and the quadrature (Q) signal.

5. The method for distance measurement of claim 4, further comprising:

converting the in-phase (I) signal into a I_dc signal having an average dc value of the in-phase (I) signal; and

converting the quadrature (Q) signal into a Q_dc signal having an average dc value of the quadrature (Q) signal,

wherein the second distance measurement is determined using the I_dc signal and the Q_dc signal.

6. The method for distance measurement of claim 5, wherein converting the in-phase (I) signal into a I_dc signal comprises:

low pass filtering the in-phase (I) signal to remove the ac component.

7. The method for distance measurement of claim 5, wherein converting the quadrature (Q) signal into a Q_dc signal comprises:

low pass filtering the quadrature (Q) signal to remove the ac component.

8. The method for distance measurement of claim 5, further comprising:

converting the I_dc signal into a first digital output (I₁) signal; and

converting the Q_dc signal into a second digital output (Q₁) signal,

wherein the second distance measurement is determined using the I₁ signal and the Q₁ signal.

9. The method for distance measurement of claim 8, further comprising:

evaluating an I_z variable from the I₁ signal; and

evaluating a Q_z variable from the Q₁ signal,

wherein the second distance measurement is determined using the I_z variable and the Q_z variable.

10. A system for measuring distance using a radio system, comprising:

a coarse distance measurement circuit to measure a coarse distance between a first radio transceiver and a second radio transceiver, the coarse distance representing a first distance measurement between the first radio transceiver and the second radio transceiver in coarse resolution; and

a fine distance measurement circuit to measure a fine distance between the first radio transceiver and the second radio transceiver, the fine distance representing a second distance measurement between the first radio transceiver and the second radio transceiver in fine resolution,

wherein the distance between the first radio transceiver and the second radio transceiver is determined using the first distance measurement in conjunction with the second distance measurement.

11. The system for measuring distance of claim 10, further comprising:

a transmit time base generator to generate a transmit timing signal;

a receive time base generator to generate a receive timing signal; and

a time delay signal generator to generate a time delay signal based on the transmit timing signal and the receive timing signal,

wherein the first distance measurement is determined using the time delay signal.

12. The system for measuring distance of claim 11, further comprising:

a means for generating a first timing signal, TX(I), using the transmit timing signal;

a means for generating a second timing signal, RX, using the receive timing signal; and

a means for generating a third timing signal, TX(Q), using at least one of the transmit timing signal and TX(I).

13. The system for measuring distance of claim 12, further comprising:

an in-phase (I) signal generator to generate an in-phase (I) signal using the TX(I) and RX signals; and

a quadrature (Q) signal generator to generate a quadrature (Q) signal using the TX(Q) and RX signals,

wherein the second distance measurement is determined using the in-phase (I) signal and the quadrature (Q) signal.

14. The system for measuring distance of claim 13, further comprising:

a first converter to convert the in-phase (I) signal into a I_dc signal having an average dc value of the in-phase (I) signal; and

a second converter to convert the quadrature (Q) signal into a Q_dc signal having an average dc value of the quadrature (Q) signal,

wherein the second distance measurement is determined using the I_dc signal and the Q_dc signal.

15. The system for measuring distance of claim 14, wherein the first converter comprises:

a low pass filter to remove the ac component from the in-phase (I) signal.

16. The system for measuring distance of claim 14, wherein the second converter comprises:

a low pass filter to remove the ac component from the quadrature (Q) signal.

17. The system for measuring distance of claim 14, further comprising:

a first A/D converter to convert the I_dc signal into a first digital output (I₁) signal; and

a second A/D converter to convert the Q_dc signal into a second digital output (Q₁) signal,

wherein the second distance measurement is determined using the I₁ signal and the Q₁ signal.

18. The system for measuring distance of claim 17, further comprising:

a processor for evaluating an I_z variable from the I₁ signal and a Q_z variable from the Q₁ signal,

wherein the second distance measurement is determined using the I_z and Q_z variables.

19. A radio transceiver, comprising:

a coarse distance measurement circuit to measure a coarse distance between the first radio transceiver and a second radio transceiver, the coarse distance representing a first distance measurement between the first radio transceiver and the second radio transceiver in coarse resolution; and

a fine distance measurement circuit to measure a fine distance between the first radio transceiver and the second radio transceiver, the fine distance representing a second distance measurement between the first radio transceiver and the second radio transceiver in fine resolution,

wherein the distance between the first radio transceiver and the second radio transceiver is determined using the first distance measurement in conjunction with the second distance measurement.

20. A method for measuring distance, comprising:

performing a coarse distance measurement of a distance between a first radio transceiver and a second radio transceiver, said coarse distance measurement having a first resolution;

performing a fine distance measurement of the distance between the first radio transceiver and the second radio transceiver, said fine distance measurement having a second resolution that is more precise than said first resolution; and

determining the distance between the first radio transceiver and the second radio transceiver using said coarse distance measurement and said fine distance measurement.

21. The method for measuring distance of claim 20, wherein said second resolution corresponds to the first resolution divided by an integer greater than 1.

22. The method for measuring distance of claim 20, wherein said fine distance measurement is performed before, after or parallel to performing said coarse distance measurement.

23. The method for measuring distance of claim 20, wherein each of said first radio transceiver and said second radio transceiver comprises one of a cellular phone, a PCS phone, an impulse radio, and a non-impulse radio.

24. The method for measuring distance of claim 20, wherein each of said first radio transceiver and said second radio transceiver uses an optical signal.

25. The method for measuring distance of claim 24, wherein said optical signal is generated by at least one of a laser and a light emitting diode (LED).