Establishing positions of locating field detectors and path mapping in underground boring tool applications

In a system for tracking the position of a boring tool in the ground as the boring tool moves along an underground path which lies within a region, said boring tool including means for transmitting an electromagnetic locating signal and said system including an above ground arrangement for receiving the electromagnetic locating signal for use in establishing the position of the boring tool, a method comprising the steps of:

• a) providing at least two above ground detectors as part of said arrangement each of which is configured for receiving said locating signal;
• b) locating said detectors at initial positions in said region within a dipole range of said electromagnetic locating signal transmitted from the boring tool at a first, start position;
• c) receiving said electromagnetic locating signal using said detectors with said boring tool first at said start position to produce a first set of electromagnetic data;
• d) moving the boring tool to a second position;
• e) receiving said electromagnetic locating signal using said detectors with said boring tool at said second position to produce a second set of electromagnetic data;
• and
• f) determining absolute positions of the detectors within said region using certain information including said first and second sets of electromagnetic data in a predetermined way.

In a system for tracking the position of a boring tool in the ground as the boring tool moves along an underground path which lies within a region, said boring tool including means for transmitting an electromagnetic locating signal and said system including an above ground arrangement for receiving the electromagnetic locating signal, an improvement comprising the steps of:

• a) providing at least two above ground detectors, each of which is configured for receiving said locating signal;
• b) locating said detectors at initial positions in said region within range of said electromagnetic locating signal transmitted from the boring tool at its initial position;
• c) providing transmitter means forming one part of at least a first one of said detectors for transmitting a relative locating signal to other detectors in a setup mode;
• d) receiving said relative locating signal using a second one of said detectors in said setup mode;
• and
• e) determining the position of the second detector relative to the first detector based on the received relative locating signal.

In a system for tracking the position of a boring tool in the ground as the boring tool moves along an underground path which lies within a region, said boring tool including means for transmitting an electromagnetic locating signal and said system including an above ground arrangement for receiving the electromagnetic locating signal within a dipole range of the boring tool, an improvement in establishing an intended path for said boring tool within said region, the improvement comprising the steps of:

• a) providing at least two detectors as part of said above ground arrangement, each detector being configured for receiving the electromagnetic locating signal;
• b) with the boring tool at a start position, locating the above ground detectors at initial fixed positions within said dipole range of said boring tool in an initial portion of said region for receiving the electromagnetic locating signal as the boring tool is later guided along an initial segment of the intended path within said dipole range of said boring tool;
• c) establishing absolute positions of said detectors within the initial portion of said region;
• d) mapping the initial segment of said intended path through the initial portion of said region in a particular way using said detectors;
• e) moving the detectors in a predetermined way to new locations within an adjacent, new portion of said region including an adjacent, new segment of said intended path;
• and
• f) without moving the boring tool from its start position, mapping the new segment of the intended path in said particular way through the new portion of said region through which the boring tool will later pass after having passed through the initial portion of the region.

In a system for tracking the position of a boring tool in the ground as the boring tool moves along an underground path which lies within a region, said boring tool including means for transmitting an electromagnetic locating signal and said system including an above ground arrangement for receiving the electromagnetic locating signal for use in establishing the position of the boring tool, a method comprising the steps of

• a) providing an above ground detector as part of said arrangement which is configured for receiving said locating signal;
• b) locating the detector at an initial position in said region within a dipole range of said electromagnetic locating signal transmitted from the boring tool at a first, start position;
• c) receiving said electromagnetic locating signal using said detector with said boring tool first at said start position to produce a first set of electromagnetic data;
• d) moving the boring tool to a second position;
• e) receiving said electromagnetic locating signal using said detector with said boring tool at said second position to produce a second set of electromagnetic data;
• and
• f) determining absolute positions of the detector and the boring tool within said region using certain information including said first and second sets of electromagnetic data in a predetermined way.

In a system in which a boring tool is moved through the ground having a pitch orientation in a region, an improvement for steering the boring tool using an electromagnetic locating signal which is transmitted from the boring tool as the boring tool moves through the ground, the improvement comprising the steps of:

• a) establishing a target location towards which the boring tool is to be steered;
• b) selecting a flux pathline having a pathline slope and extending between the boring tool and the target location by specifying a selected pitch orientation for the boring tool upon reaching the target location, the selected flux pathline defining a plane in said region;
• and
• c) guiding the boring tool along the selected flux pathline to the target location such that a particular ratio between a vertical component of the locating field measured within the plane of the selected flux pathline and a horizontal component of the locating field measured within the plane of the selected path flux line is present at said target location which particular ratio is equal to the specified pitch orientation of the boring tool at the target location.