Underground utility line locator and method for use

Patent metadata

Field	Value
Publication number	US-10042074-B2
Application number	US-201514729232-A
Country	US
Kind code	B2
Filing date	Jun 3, 2015
Priority date	Jun 5, 2014
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A locator for determining the location of a buried utility line from an offset position. The locator has a top peak antenna, a bottom peak antenna, and a null antenna. The locator is tilted until the null antenna is pointed directly at the utility line with the top and bottom peak antennas disposed in a locating plane that is substantially vertical and perpendicular to the line. The tilt angle of the locator and the direct distance between the locator and the utility is measured. The tilt angle and direct distance are used by the processor to determine the vertical and horizontal distances between the locator and the utility.

First claim

What is claimed is:

1. A system for locating an underground utility line, wherein the utility line emits an electromagnetic field, the system comprising:
one and only one top antenna supported on the frame proximate the top of the frame, in which the top antenna detects the electromagnetic field on only one axis;
one and only one bottom antenna supported proximate the bottom of the frame and separated from the top antenna by a known distance, in which the bottom antenna detects the electromagnetic field on only one axis;
a null antenna supported on the frame and disposed at an orientation orthogonal to the top antenna and the bottom antenna;
wherein the top antenna and the bottom antenna define a locating plane;
an inclinometer supported on the frame to measure a tilt angle of the frame within the locating plane; and
a processor supported on the frame to determine a direct distance between the frame and the underground utility line using a signal strength of the electromagnetic field received at the top antenna compared to a signal strength received at the bottom antenna with the null antenna pointed substantially at the utility line;
wherein the processor determines a horizontal distance between the frame and a point on the ground above the utility line using the direct distance and the tilt angle of the frame.

2. The system of claim 1 further comprising a display having a visual indicator to guide the frame to a position where the null antenna is pointed substantially at the utility line and to indicate when the frame is pointed substantially at the utility line.

3. The system of claim 2 wherein the display shows a vertical distance; wherein the vertical distance comprises the distance from a point proximate the bottom of the frame to a point on the utility line that intersects the locate plane.

4. The system of claim 2 further comprising:
a global positioning satellite receiver; and
a storage media to store a global position of the frame, the horizontal distance, and the vertical distance.

5. The system of claim 1 wherein the utility line is perpendicular to the locating plane when the direct distance is determined.

6. The system of claim 1 wherein the inclinometer comprises an accelerometer.

7. The system of claim 1 further comprising a compass antenna that is orthogonal to the null antenna, the top antenna, and the bottom antenna.

8. The system of claim 7 wherein the compass antenna detects the signal strength of the electromagnetic field and transmits a compass signal to the processor, wherein the processor uses the compass signal and a signal from the top antenna or the bottom antenna to determine an angle between the utility line and the frame in a horizontal plane.

9. The system of claim 8 wherein when the locate plane is not perpendicular to the utility line a shortest horizontal distance from a point on the ground above the utility line and the bottom of the frame is determined by the processor using the angle between the utility line and the frame in the horizontal plane.

10. The system of claim 2 wherein the display comprises a visual indication of an orientation of the utility line relative to the frame.

11. The system of claim 1 wherein the null antenna is disposed in the locating plane.

12. A method for determining the location of an underground utility line using a hand-held locator, the method comprising:
positioning the locator at a point that is laterally displaced from the utility line;
pointing a bottom of the locator toward the utility line by tilting the locator until a minimum signal is measured at a null antenna;
measuring a tilt angle of the locator;
measuring a signal strength of an electromagnetic field transmitted from the utility line at one and only one top antenna and at one and only one bottom antenna, wherein the top antenna and the bottom antenna are separated by a known distance, and wherein the top antenna and the bottom antenna each detect the electromagnetic field on only one axis;
processing the measured signal strength of the top antenna and the bottom antenna to determine a direct distance between the locator and the utility line;
determining a horizontal distance to the utility line based on the tilt angle of the locator and the direct distance; and
displaying the horizontal distance.

13. The method of claim 12 further comprising rotating the locator to orient the locator so that the locate plane is substantially perpendicular to the line.

14. The method of claim 12 further comprising following visual indicators displayed on a screen to locate a peak-null signal with the bottom and null antennas.

15. The method of claim 12 further comprising determining a global position of the locator using a global positioning satellite receiver and storing the direct distance, the vertical distance, and the horizontal distance.

16. The method of claim 12 further comprising determining a vertical distance to the utility line based on the tilt angle of the locator and the direct distance and displaying the vertical distance.

17. A system for determining the location of a utility line that emits an electromagnetic field, the utility line being disposed at least partially under a surface obstruction that prevents placing the locator directly above the utility line, the system comprising:
a locator comprising:
a frame having a top and a bottom;
a display;
one and only one top antenna disposed proximate the top of the frame, in which the top antenna detects the electromagnetic field on only one axis;
one and only one bottom antenna disposed proximate the bottom of the frame and separated from the top antenna a known distance, in which the bottom antenna detects the electromagnetic field on only one axis;
a null antenna supported on the frame orthogonal to the bottom antenna;
an inclinometer supported by the frame to detect a tilt angle of the frame;

a processor to determine a direct distance between the locator and the underground utility line using a signal strength of the electromagnetic field received at the top antenna compared to a signal strength received at the bottom antenna with the null antenna pointed substantially at the utility line;
wherein the processor uses the direct distance and the tilt angle of the frame to calculate a shortest horizontal distance between the locator and a point on the ground above the utility line and within a plane defined by the top antenna and the bottom antenna; and
wherein the processor sends a display signal to the display to show the direct distance and the shortest horizontal distance.

18. The system of claim 17 wherein the display comprises a visual indicator to direct movement of the frame to a position where the null antenna is pointed substantially at the utility line.

19. The system of claim 17 further comprising:
a global positioning satellite receiver; and
a storage media to store a global position of the locator, the horizontal distance, and the vertical distance.

20. The system of claim 17 wherein the top antenna, the bottom antenna, and null antenna are disposed in a single plane, wherein the utility line is perpendicular to the plane when the direct distance is determined.

21. The system of claim 17 wherein the top antenna, the bottom antenna, and null antenna are disposed in a single plane, wherein the utility line is disposed at an angle to the plane of greater than or less than 90 degrees when the direct distance is determined.

22. The system o

Assignees

• Charles Machine Works

Inventors

• Bailey Brian K

Classifications

• G01V3/08 Primary

  operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) · CPC title

• G01V3/15

  specially adapted for use during transport, e.g. by a person, vehicle or boat · CPC title

• G01V3/165 Primary

  operating with magnetic or electric fields produced or modified by the object or by the detecting device (with electromagnetic waves G01V3/17) · CPC title

• G01V3/081

  the magnetic field is produced by the objects or geological structures (characterised by the method of magnetic field measurement G01R33/00) · CPC title