Boring technique using locate point measurements for boring tool depth determination

• US 5,933,008 A
• Filed: 12/15/1997
• Issued: 08/03/1999
• Est. Priority Date: 03/14/1996
• Status: Expired due to Term

• Current Assignee: Merlin Technologies Incorporated
• Original Assignee: Digital Control Incorporated
• Inventors: Mercer, John E.
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US08/990,498
• Time in Patent Office: 596 Days
• Field of Search: 324/326, 324/327, 324/328, 324/329, 324/207.11, 324/207.12, 324/207.26, 175/45, 166/250.01, 166/255.1
• US Class Current: 324/326
• CPC Class Codes: E21B 47/0232 at least one of the energy sources or one of the detectors being located on or above the ground surface
• CPC Class Codes: G01V 3/165 operating with magnetic or electric fields produced or modified by the object or by the detecting device with electromagnetic waves G01V3/17
• CPC Class Codes: G01V 3/26 operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device with electromagnetic waves G01V3/30

Abstract

A method is disclosed as part of an overall process in which a boring tool is moved through the ground within a given region along a particular path in an orientation which includes pitch. A locating signal is transmitted from the boring tool which exhibits negative locate points at the surface of the ground. The method establishes the depth of the boring tool at a particular position by identifying a negative locate point corresponding to the particular position of the boring tool along the particular path. Thereafter, a signal strength of the locating signal is measured at the negative locate point. The pitch of the boring tool is then determined at the particular position of the boring tool. Using the measured signal strength and the determined pitch, the depth of the boring tool beneath the surface of the ground is established at the particular point.

Claims

1. In an overall process in which a boring tool is moved through the ground within a given region along a particular path while transmitting a locating signal, said boring tool moving in an orientation which includes pitch, said locating signal exhibiting negative locate points at the surface of the ground, a method of establishing the depth of said boring tool at a particular position, said method comprising the steps of:

(a) identifying a negative locate point corresponding to said particular position of the boring tool along said particular path;

(b) measuring a signal strength of the locating signal at said negative locate point;

(c) determining the pitch of the boring tool at said particular position; and

(d) using the measured signal strength and the determined pitch, establishing the depth of said boring tool beneath the surface of the ground at said particular position.

2. The method of claim 1 wherein said negative locate point is a forward locate point.

3. The method of claim 2 wherein said step of using the measured signal strength and the determined pitch includes the step of establishing a forward distance which is a horizontal distance between the forward locate point and a point directly above the boring tool.

4. The method of claim 1 further comprising the step of:

(e) displaying said depth.