Two-source magnetic field guidance system
First Claim
1. A magnetic field guidance system, comprising:
- a movable carrier;
a fixed carrier;
first and second magnetic field sources located at a first one of said movable and fixed carriers;
said first magnetic field source including a solenoid having a directional axis and a source of low-frequency alternating current connected to said solenoid to produce a first, axial magnetic field surrounding said first one of said movable and fixed carriers;
said second magnetic field source including a magnet producing a second magnetic field perpendicular to said axial magnetic field and surrounding said first one of said movable and fixed carriers;
a highly sensitive three-axis magnetic field detector mounted at a second one of said movable and fixed carriers said magnetic field detector being responsive to vector components of said axial and perpendicular magnetic fields to produce corresponding vector output signals for determining the deviation from perpendicularity of said axial and perpendicular magnetic fields at the location of said detector, whereby the angle between said directional axis and a radial line between the locations of said first and second carriers is determined.
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Accused Products
Abstract
A magnetic field guidance system for guiding a movable carrier such as a drill assembly with respect to a fixed target includes a pair of magnetic field sources at one location, such as the carrier, and a highly sensitive magnetic field detector at the other location, or target. The first field source is driven by an alternating current to produce a low frequency alternating axial field, while the second source is a magnet which produces a field perpendicular to the axis of the first field. Where the magnetic field sources are mounted on a rotatable drill assembly, the second source may be a permanent magnet which rotates with the drill assembly. The detector may be a fluxgate magnetometer which senses the direction of the target location with respect to the direction of the axial field by determining the deviation from perpendicular of the two magnetic fields at the target location.
163 Citations
18 Claims
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1. A magnetic field guidance system, comprising:
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a movable carrier; a fixed carrier; first and second magnetic field sources located at a first one of said movable and fixed carriers; said first magnetic field source including a solenoid having a directional axis and a source of low-frequency alternating current connected to said solenoid to produce a first, axial magnetic field surrounding said first one of said movable and fixed carriers; said second magnetic field source including a magnet producing a second magnetic field perpendicular to said axial magnetic field and surrounding said first one of said movable and fixed carriers; a highly sensitive three-axis magnetic field detector mounted at a second one of said movable and fixed carriers said magnetic field detector being responsive to vector components of said axial and perpendicular magnetic fields to produce corresponding vector output signals for determining the deviation from perpendicularity of said axial and perpendicular magnetic fields at the location of said detector, whereby the angle between said directional axis and a radial line between the locations of said first and second carriers is determined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification