Multi-gimbaled borehole navigation system
First Claim
1. An omnidirectional borehole navigation system comprising:
- a housing for traversing a borehole;
an outer gimbal connected to said housing and at least two stacked inner gimbals that are connected to said outer gimbal, said inner gimbals each having an axis parallel to one another and perpendicular to an axis of the outer gimbal;
at least one inertial sensor located on each inner gimbal, the at least one inertial sensor selected from at least one gyro and at least one accelerometer, the gyros having input axes that span three dimensional space, and the accelerometers having input axes that span three dimensional space;
one or more gyro circuits within the housing and responsive to the at least one gyro to produce the inertial angular rate about each gyro input axis;
one or more accelerometer circuits within the housing and responsive to the at least one accelerometer to produce the non-gravitational acceleration along each accelerometer input axis;
a processor responsive to said gyro circuits and said accelerometer circuits for determining the attitude and the position of said housing in the borehole;
an outer gimbal drive system for controlling the orientation of the outer gimbal; and
an inner gimbal drive system for controlling the orientation of each of the inner gimbals.
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Accused Products
Abstract
An omnidirectional borehole navigation system comprising a housing for traversing a borehole; an outer gimbal connected to said housing and at least two or more stacked inner gimbals that are nested in and connected to said outer gimbal, said inner gimbals each having an axis parallel to one another and perpendicular to the outer gimbal; at least one inertial sensor located on each inner gimbal, the at least one inertial sensor including at least one gyro or accelerometer, the gyros having input axes that span three dimensional space and the accelerometers having input axes that span three dimensional space; one or more gyro circuits within the housing and responsive to the at least one gyro to produce the inertial angular rate about each gyro input axis; one or more accelerometer circuits within the housing and responsive to the at least one accelerometer to produce the non-gravitational acceleration along each accelerometer input axis; a processor responsive to said gyro circuits and said accelerometer circuits for determining the attitude and the position of said housing in the borehole; an outer gimbal drive system with complete rotary freedom; and an inner gimbal drive system for controlling the orientation of each of the inner gimbals. The drive system that controls the stacked inner gimbals may be a rack and pinion gear, or a gear train such as a bicycle chain gear rotating the inner gimbals in parallel between stops while maintaining the input axis orthogonality of gyro triads and the input axis orthogonality of accelerometer triads. The inner gimbal stops may be elastic to allow for small misalignments in the inner gimbal drive system.
57 Citations
44 Claims
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1. An omnidirectional borehole navigation system comprising:
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a housing for traversing a borehole;
an outer gimbal connected to said housing and at least two stacked inner gimbals that are connected to said outer gimbal, said inner gimbals each having an axis parallel to one another and perpendicular to an axis of the outer gimbal;
at least one inertial sensor located on each inner gimbal, the at least one inertial sensor selected from at least one gyro and at least one accelerometer, the gyros having input axes that span three dimensional space, and the accelerometers having input axes that span three dimensional space;
one or more gyro circuits within the housing and responsive to the at least one gyro to produce the inertial angular rate about each gyro input axis;
one or more accelerometer circuits within the housing and responsive to the at least one accelerometer to produce the non-gravitational acceleration along each accelerometer input axis;
a processor responsive to said gyro circuits and said accelerometer circuits for determining the attitude and the position of said housing in the borehole;
an outer gimbal drive system for controlling the orientation of the outer gimbal; and
an inner gimbal drive system for controlling the orientation of each of the inner gimbals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An omnidirectional borehole navigation system comprising:
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a housing for traversing a borehole;
at least one outer gimbal connected to said housing and at least two stacked inner gimbals that are nested in and connected to said outer gimbal, said inner gimbals each having an axis parallel to one another and perpendicular to an axis of the outer gimbal;
at least one inertial sensor located on each inner gimbal, the at least one inertial sensor including at least one gyro or accelerometer, the gyros having input axes that span three dimensional space and the accelerometers having input axes that span three dimensional space;
an outer gimbal drive system;
an inner gimbal drive system including an inner gimbal drive motor, a rotary-to-linear gear connected to the inner gimbal drive motor, a rack connected to the rotary-to-linear gear and a plurality of pinions each engaging the rack, each pinion connected to an inner gimbal for maintaining the gyro input axes at substantially an orthogonal triad and the accelerometer input axes at substantially an orthogonal triad;
one or more gyro circuits within the housing and responsive to the at least one gyro to produce the inertial angular rate about each gyro input axis;
one or more accelerometer circuits within the housing and responsive to the at least one accelerometer to produce the non-gravitational acceleration along each accelerometer input axis; and
a processor responsive to said gyro logic circuits and said accelerometer logic circuits for determining the attitude and the position of said housing in its borehole. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. An omnidirectional borehole navigation system comprising:
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a housing for traversing a borehole;
an outer gimbal connected to said housing and at least two stacked inner gimbals that are connected to said outer gimbal, said inner gimbals each having an axis parallel to one another and perpendicular to an axis of the outer gimbal;
at least one inertial sensor located on each inner gimbal, the at least one inertial sensor selected from at least one gyro and at least one accelerometer, the gyros having input axes that span three dimensional space and the accelerometers having input axes that span three dimensional space, the borehole navigation system determining the attitude and the position of said housing in the borehole. - View Dependent Claims (39, 40, 41, 42, 43)
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44. An omnidirectional borehole navigation system comprising:
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a housing for traversing a borehole;
at least one outer gimbal connected to said housing and three stacked inner gimbals that are nested in and connected to said outer gimbal, said inner gimbals each having an axis parallel to one another and perpendicular to an axis of the outer gimbal;
one MEMS gyro and one MEMS accelerometer located in each inner gimbal, the gyros having input axes substantially forming an orthogonal triad and the accelerometers having input axes substantially forming an orthogonal triad at each position of the inner gimbals;
an outer gimbal drive system coupled to the at least one outer gimbal;
an inner gimbal drive system including an inner gimbal drive motor, a rotary-to-linear gear connected to the inner gimbal drive motor, a rack connected to the rotary-to-linear gear and a plurality of pinions each engaging the rack, each pinion connected to an inner gimbal for maintaining the gyro input axes at substantially an orthogonal triad and the accelerometer input axes at substantially an orthogonal triad;
one or more gyro circuits within the housing and responsive to the at least one gyro to produce the inertial angular rate about each gyro input axis;
one or more accelerometer circuits within the housing and responsive to the at least one accelerometer to produce the non-gravitational acceleration along each accelerometer input axis; and
a processor responsive to said gyro logic circuits and said accelerometer logic circuits for determining the attitude and the position of said housing in its borehole.
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Specification