Buried line locator with integral position sensing

• US 7,120,564 B2
• Filed: 04/03/2003
• Issued: 10/10/2006
• Est. Priority Date: 04/03/2003
• Status: Active Grant

• Current Assignee: Metrotech Corporation (L'Air Liquide SA)
• Original Assignee: Metrotech Corporation (L'Air Liquide SA)
• Inventors: Pacey, Gordon
• Primary Examiner(s): Bui, Bryan
• Application Number:
  US10/407,705
• Publication Number:
  US 20050096883A1
• Time in Patent Office: 1,286 Days
• Field of Search: 702 4- 6, 702/38, 702/40, 702/85, 702/94, 702/97, 702/141, 702/150, 702/152, 702/189, 702/193, 324326-327, 342/124, 340/854.8
• US Class Current: 702/193
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12

Abstract

A device for detecting and compensating field distortion in underground line locators by means of mapping the field-strength of the field generated by electrical currents within the buried line. Signals from the underground structure can be mapped with respect to the position of the device. From the map, distortions from the expected signals can be determined, indicating interference from other structures or errors in detected location of the structure.

Claims

1. A line locator system, comprising:

at least one detector that measures a magnitude of an electromagnetic field;

an accurate spatial location system that provides a spatial position relative to a reference position located near an area-of-interest; and

a processing system containing information including data that associates the magnitude of the electromagnetic field with the spatial position, wherein the information is stored in the processing system in a manner that allows recall of the data from the processing system by access via either the magnitude of the electromagnetic field or the spatial position, alone;

wherein determining the difference of the position of the line locator with respect to the reference position comprises detecting motion by the line locator and determining the difference of position based upon motion of the line locator.

12. The line locator system of claim 1, wherein the accurate spatial location system includes one or more accelerometers.

13. The line locator system of claim 1, wherein the accurate spatial location system includes a receiver configured to receive signals from one or more local transmitters positioned relative to the reference position, the accurate spatial location system determining a position of the line locator with respect to the reference position based upon the signals received at an antenna of the receiver.

14. The line locator system of claim 1, wherein the accurate spatial location system includes a range finder, the range finder being configured to determine motion of the line locator system based upon detected radiation reflection from an object positioned relative to the reference position.

15. The line locator system of claim 1, further comprising a transmitter coupled to induce the electromagnetic field from an underground line.

16. The line locator system of claim 1 wherein the processing system determines whether a distortion exists in the electromagnetic field.

17. The line locator system of claim 1, wherein the processing system stores the magnitude of the electromagnetic field and the spatial position in a memory.

18. The line locator system of claim 17, wherein the processing system determines positions of underground lines based on the magnitude of the electromagnetic field and the spatial positions stored in the memory.

2. A line locator system comprising:

at least one detector that measures a magnitude of an electromagnetic field;

an accurate spatial location system that provides a spatial position relative to a reference position located near an area-of-interest; and

a processing system containing information including data that associates the magnitude of the electromagnetic field with the spatial position, wherein the information is stored in the processing system in a manner that allows recall of the data from the Processing system by access via either the magnitude of the electromagnetic field or the spatial position, alone;

wherein the processing system generates a map of the electromagnetic field at a plurality of spatial positions.

19. The line locator system of claim 2, wherein the accurate spatial location system includes one or more accelerometers.

20. The line locator system of claim 2, wherein the accurate spatial location system includes a receiver configured to receive signals from one or more local transmitters positioned relative to the reference position, the accurate spatial location system determining a position of the line locator with respect to the reference position based upon the signals received at an antenna of the receiver.

21. The line locator system of claim 2, wherein the accurate spatial location system includes a range finder, the range finder being configured to determine motion of the line locator system based upon detected radiation reflection from an object positioned relative to the reference position.

22. The line locator system of claim 2, further comprising a transmitter coupled to induce the electromagnetic field from an underground line.

23. The line locator system of claim 2, wherein the processing system determines whether a distortion exists in the electromagnetic field.

24. The line locator system of claim 2, wherein the processing system stores the magnitude of the electromagnetic field and the spatial position in a memory.

25. The line locator system of claim 24, wherein the processing system determines positions of underground lines based on the magnitude of the electromagnetic field and the spatial positions stored in the memory.

3. A line locator system comprising:

at least one detector that measures a magnitude of an electromagnetic field;

an accurate spatial location system that provides a spatial position relative to a reference position located near an area-of-interest; and

a processing system containing information including data that associates the magnitude of the electromagnetic field with the spatial position, wherein the information is stored in the processing system in a manner that allows recall of the data from the processing system by access via either the magnitude of the electromagnetic field or the spatial position, alone;

wherein the magnitude of the electromagnetic field and the spatial position are downloaded to a computer, the computer comparing the electromagnetic field and the spatial position with expected values of the electromagnetic field and the spatial position.

26. The line locator system of claim 3, wherein the computer determines positions of underground lines based on the electromagnetic field and the spatial position.

27. The line locator system of claim 3, wherein the accurate spatial location system includes one or more accelerometers.

28. The line locator system of claim 3 wherein the accurate spatial location system includes a receiver configured to receive signals from one or more local transmitters positioned relative to the reference position, the accurate spatial location system determining a position of the line locator with respect to the reference position based upon the signals received at an antenna of the receiver.

29. The line locator system of claim 3, wherein the accurate spatial location system includes a range finder, the range finder being configured to determine motion of the line locator system based upon detected radiation reflection from an object positioned relative to the reference position.

30. The line locator system of claim 3, further comprising a transmitter coupled to induce the electromagnetic field from an underground line.

31. The line locator system of claim 3, wherein the processing system determines whether a distortion exists in the electromagnetic field.

32. The line locator system of claim 3, wherein the processing system stores the magnitude of the electromagnetic field and the spatial position in a memory.

33. The line locator system of claim 32, wherein the processing system determines positions of underground lines based on the magnitude of the electromagnetic field and the spatial positions stored in the memory.

4. A method for determining the position of underground lines utilizing a line locator, the method comprising the steps of:

determining a magnitude of a signal detected by the line locator at a position;

determining a difference of the position of the line locator with respect to a reference position; and

associating information, within a data processing system, including first data representative of the difference in position and second data representative of the magnitude of the signal at the position, such that the first data is associated with the second data in a manner that allows recall of information from the processing system by entry of either the first data or the second data, alone;

wherein determining the difference of the position of the line locator with respect to the reference position comprises detecting motion by the line locator and determining the difference of position based upon motion of the line locator.

34. The method of claim 4 wherein detecting motion by the line locator comprises detecting acceleration of the line locator.

35. The method of claim 4, wherein the signal is related to a magnetic field and the method further comprises determining a distortion of the magnetic field based upon the difference in position and the magnitude of the magnetic field.

36. The method of claim 35 further comprising providing a distortion indication signal to a user of the line locator when a determination is made that one or more lines are underground in the area.

37. The method of claim 35 further comprising correcting the magnitude of the electromagnetic field that is detected based upon the distortion.

38. The method of claim 4, wherein determining the difference in position comprises determining a difference in a plane between the position and the reference position.

39. The method of claim 4, wherein determining the difference in position comprises determining a difference in x and y coordinates between the position and reference position.

40. The method of claim 39, wherein determining a difference in x and y coordinates comprises determining a difference in x, y, and z coordinates.

41. The method of claim 4, wherein determining the difference in position comprises determining a distance of the line locator with respect to a fixed landmark.

5. A method for determining the position of underground lines utilizing a line locator, the method comprising the steps of:

determining a magnitude of a signal detected by the line locator at a position;

determining a difference of the position of the line locator with respect to a reference position; and

associating information, within a data processing system, including first data representative of the difference in position and second data representative of the magnitude of the signal at the position, such that the first data is associated with the second data in a manner that allows recall of information from the processing system by entry of either the first data or the second data, alone;

wherein determining the magnitude comprises determining the magnitude of the signal at a plurality of positions, wherein determining the difference of the position comprises determining a difference of each the plurality of positions with respect to the reference position, and the method further comprising generating a map based upon each of the magnitudes and associated differences of position.

42. The method of claim 5 further comprising determining a number of underground lines in an area underground of the plurality of positions based upon the shape of the signal.

43. The method of claim 5 further comprising determining a position of one fine of the one or more lines based upon the map.

6. A method for determining the position of underground lines utilizing a line locator, the method comprising the steps of:

determining a magnitude of a signal detected by the line locator at a position;

determining a difference of the position of the line locator with respect to a reference position, wherein determining the difference in position comprises determining a difference in x, v and z coordinates between the position and reference position; and

associating information, within a data processing system, including first data representative of the difference in position and second data representative of the magnitude of the signal at the position, such that the first data is associated with the second data in a manner that allows recall of information from the processing system by entry of either the first data or the second data, alone;

wherein the difference in the x, y, and z coordinates between the position and reference position is determined utilizing at least one accelerometer to detect motion of the position in the x, y, and z coordinates.

7. A method for determining the position of underground lines utilizing a line locator, the method comprising the steps of:

determining a magnitude of a signal detected by the line locator at a position;

determining a difference of the position of the line locator with respect to a reference position; and

associating information, within a data processing system, including first data representative of the difference in position and second data representative of the magnitude of the signal at the position, such that the first data is associated with the second data in a manner that allows recall of information from the processing system by entry of either the first data or the second data, alone;

wherein determining the difference in position comprises tri-laterating the position of the line locator based upon signals received from two or more local transmitters.

8. A method for determining the position of underground lines utilizing a line locator, the method comprising the steps of:

determining a magnitude of a signal detected by the line locator at a position;

determining a difference of the position of the line locator with respect to a reference position; and

associating information, within a data processing system, including first data representative of the difference in position and second data representative of the magnitude of the signal at the position, such that the first data is associated with the second data in a manner that allows recall of information from the processing system by entry of either the first data or the second data, alone;

wherein determining the difference in position comprises triangulating the position of the line locator based upon signals received from one or more local transmitters.

9. A line locator for determining the position of underground lines, comprising:

at least one detector;

detection circuitry comprising an input coupled to the at least one detector and an output; and

means for determining a difference between a position of the line locator and a reference position comprising an output;

wherein the means for determining comprises means for generating a map of magnitudes of the signal at a plurality of positions, each of the plurality of positions determined by determining a difference between each of the plurality of positions and the reference position.

44. The line locator of claim 9, wherein the means for determining the difference comprises means for determining the difference in the x and y coordinates.

45. The line locator of claim 9, wherein the means for determining the difference comprises means for determining the difference in x, y, and z coordinates.

46. The line locator of claim 9, further comprising a transmitter that provides a signal a reflection of which is detected by the at least one detector.

47. The line locator of claim 9, wherein the means for determining comprises means for determining a distance between a landmark and the position of the line locator and the reference position.

10. A line locator for determining the position of underground lines, comprising:

at least one detector;

detection circuitry comprising an input coupled to the at least one detector and an output; and

means for determining a difference between a position of the line locator and a reference position comprising an output;

wherein the means for determining comprises means for triangulating the position of the line locator based upon a signal received from two or more local transmitters.

48. The line locator of claim 10, wherein the means for determining further comprises means for determining a distance between a landmark and the position of the line locator and the reference position.

11. A line locator for determining the position of underground lines, comprising:

at least one detector;

detection circuitry comprising an input coupled to the at least one detector and an output; and

means for determining a difference between a position of the line locator and a reference position comprising an output;

wherein the means for determining comprises means for tri-laterating the position of the line locator based upon a signal received from two or more local transmitters.

49. The line locator of claim 11, wherein the means for determining further comprises means for determining a distance between a landmark and the position of the line locator and the reference position.