Detector for detecting a current carrying conductor

• US 8,742,747 B2
• Filed: 12/06/2010
• Issued: 06/03/2014
• Est. Priority Date: 12/06/2010
• Status: Active Grant

• Current Assignee: Radiodetection Limited
• Original Assignee: Radiodetection Limited
• Inventors: Pearson, Richard David
• Primary Examiner(s): Baldridge, Benjamin M
• Application Number:
  US12/961,401
• Publication Number:
  US 20120139525A1
• Time in Patent Office: 1,275 Days
• Field of Search: 324/67, 702/38
• US Class Current: 324/67
• CPC Class Codes: G01R 33/123 Measuring loss due to hysteresis G01R33/14 takes precedence
• CPC Class Codes: G01V 3/081 the magnetic field is produced by the objects or geological structures characterised by the method of magnetic field measurement G01R33/00

Abstract

A locator for determining the location and/or orientation of a concealed conductor, comprising a reference field detector operable to detect an alternating magnetic field along a reference axis; a first field detector operable to detect an alternating magnetic field along a first axis; and a processor operable to calculate an in-phase component of a signal detected by the first field detector, the in-phase component being in phase with a signal detected at the reference field detector and to calculate a signal indicative of a position of the concealed conductor relative to the locator using at least the in-phase component.

Claims

1. A locator for determining the location and/or orientation of a concealed conductor, comprising:

a reference field detector that detects an alternating magnetic field along a reference axis;

a first field detector orthogonal to the reference field detector and that detects an alternating magnetic field along a first axis;

a second field detector parallel to the first field detector and orthogonal to the reference field detector, that detects an alternating magnetic field along the first axis; and

a processor programmed to calculate an in-phase component of a signal detected by the first and second field detectors, wherein the in-phase component is in-phase with a signal detected at the reference field detector, and to calculate and output an indication of a position and/or orientation of the concealed conductor relative to the locator using at least the in-phase component of the signal detected by the first and second field detectors,

wherein the first and second field detectors are configured to minimize interference from sources other than the concealed conductor.

2. The locator according to claim 1, further comprising a reference oscillator, wherein the processor is further programmed to calculate vectors representing the signals from the reference field detector and first and second field detectors, and to calculate a projection of the vector from the first and second detectors onto the vector from the reference oscillator as an in-phase component.

3. The locator according to claim 1, wherein the first axis is parallel to the reference axis, the first and second field detectors and the reference field detector are spaced apart, and the processor is programmed to calculate the distance between the concealed conductor and the locator.

4. The locator according to claim 1, wherein the first axis is at an angle to the reference axis, and the processor is programmed to calculate and output an indication of the degree of rotation of the reference axis relative to an axis of the concealed conductor.

5. The locator according to claim 4, further comprising a further field detector that detects an alternating magnetic field along a further axis, wherein the further axis is parallel to the reference axis, the further field detector and the reference field detector are spaced apart, and the processor is programmed to calculate and output an indication of the distance between the concealed conductor and the locator.

6. The locator according to claim 1, wherein the first axis is at an angle to the reference axis, and the processor is programmed to calculate and output an indication of a lateral position of the conductor relative to the first axis.

7. The locator according to claim 1, further comprising an indicator for providing an indication of the position and/or orientation of the concealed conductor using the calculated indication of the position and/or orientation of the concealed conductor relative to the locator.

8. The locator according to claim 1, wherein an output of the reference field detector is used to determine a polarity of a difference signal of outputs of the first and second field detectors.

9. A method of determining the location and/or orientation of a concealed conductor, comprising:

measuring a reference magnetic field along a reference axis;

measuring a first magnetic field along a first axis;

measuring a second magnetic field along the first axis;

calculating an in-phase component of the first and second magnetic fields, the in-phase component being in phase with the reference magnetic field; and

calculating position and/or orientation information of the concealed conductor using at least the in-phase component of the first and second magnetic fields.

10. The method according to claim 9, wherein the first axis is parallel to the reference axis, and the position information comprises a distance between the reference axis and the concealed conductor.

11. The method according to claim 9, wherein the first axis is at an angle to the reference axis and the position information comprises a lateral position of the conductor relative to the first axis.

12. The method according to claim 11, wherein the first axis is orthogonal to the reference axis.

13. The method according to claim 12, further comprising measuring a second magnetic field along a second axis, wherein the second axis is parallel to the first axis, and wherein the first axis and the second axis are orthogonal to the reference axis, and the position information comprises a lateral distance between the first axis and the concealed conductor.

14. The method according to claim 9, wherein the first axis is at an angle to the reference axis, and the orientation information comprises an indication of the degree of rotation of the reference axis relative to an axis of the concealed conductor.

15. The method according to claim 14, wherein the first axis is orthogonal to the reference axis.

16. The method according to claim 9, further comprising generating an oscillating reference signal, calculating the phase of the reference field with respect to the oscillating reference signal, calculating the phase of the first magnetic field with respect to the oscillating reference signal, and determining the in-phase component from the calculated phases and magnitudes of the reference magnetic field and the first magnetic field.

17. The method according to claim 9, wherein the measuring a first magnetic field along a first axis and the measuring a second magnetic field along the first axis steps further comprise minimizing the interference from sources other than the concealed conductor.

18. A non-volatile carrier medium storing computer readable instructions for execution by a processor in a locator for locating and/or determining orientation of a concealed conductor, the locator having a reference field detector that detects an alternating magnetic field along a reference axis;

a first field detector that detects an alternating magnetic field along a first axis;

a second field detector that detects an alternating magnetic field along a first axis;

wherein the instructions comprise instructions for controlling the processor to calculate an in-phase component of signals detected by the first and second field detectors, the in-phase component of the signals detected by the first and second field detectors being in phase with a signal detected at the reference field detector and to calculate a signal indicative of a position and/or orientation of the concealed conductor relative to the locator using at least the in-phase component detected by the first and second field detectors.

19. The carrier medium according to claim 18, wherein the instructions further comprise instructions for calculating the phase of the reference field with respect to a oscillating reference signal, calculating the phase of the first magnetic field with respect to the oscillating reference signal, and determining the in-phase component from the calculated phases and magnitudes of the magnetic field along the reference axis and the magnetic field along the first axis.

20. The carrier medium according to claim 18, wherein the instructions further comprise instructions to minimize the interference from sources other than the concealed conductor.