Gyroscopically-oriented survey tool
First Claim
1. An apparatus for determining a special orientation of a gyroscopically oriented survey tool, comprising:
- a housing having an axis;
three accelerometers mounted in the housing having their respective sensitive axis set orthogonally, a first of the axis being aligned to the axis of the housing, a second of the axis being perpendicular to the first, and a third of the axis being perpendicular to both of the first axis and the second axis; and
three gyroscopes mounted pseudo-orthogonally in the housing with their respective sensitive axis set at relative angles of other than 90 degrees, none of the axis of the gyroscopes being mounted parallel to the axis of the accelerometers, such arrangement ensuring that any housing rotation will affect at least two gyroscopes and such arrangement ensuring that any housing rotation about any non-vertical gyroscope axis will affect at least one accelerometer;
means for using corroborating data from the accelerometers to correct offset factors of the gyroscopes;
means for using corroborating data from the accelerometers to correct scale factors of those of the gyroscopes having a non-vertical sensitive axis; and
means for correcting the scale factor of one of the gyroscopes having a vertical sensitive axis by using data from non-vertical gyroscopes whole scale factors have been corrected.
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Accused Products
Abstract
A gyroscopically-oriented survey tool, includes a housing having an axis. Three accelerometers are mounted in the housing with their axis set orthogonally. A first of the axis is aligned to the axis of the housing. A second of the axis is perpendicular to the first. A third of the axis is perpendicular to both of the first and the second. Three gyroscopes are mounted pseudo-orthogonally in the housing with their axis set at relative angles of other than 90 degrees. None of the axis of the gyroscopes are mounted parallel to the axis of the accelerometers. This configuration permits data from the accelerometers to be used to check the quality of data from the gyroscopes.
68 Citations
10 Claims
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1. An apparatus for determining a special orientation of a gyroscopically oriented survey tool, comprising:
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a housing having an axis; three accelerometers mounted in the housing having their respective sensitive axis set orthogonally, a first of the axis being aligned to the axis of the housing, a second of the axis being perpendicular to the first, and a third of the axis being perpendicular to both of the first axis and the second axis; and three gyroscopes mounted pseudo-orthogonally in the housing with their respective sensitive axis set at relative angles of other than 90 degrees, none of the axis of the gyroscopes being mounted parallel to the axis of the accelerometers, such arrangement ensuring that any housing rotation will affect at least two gyroscopes and such arrangement ensuring that any housing rotation about any non-vertical gyroscope axis will affect at least one accelerometer; means for using corroborating data from the accelerometers to correct offset factors of the gyroscopes; means for using corroborating data from the accelerometers to correct scale factors of those of the gyroscopes having a non-vertical sensitive axis; and means for correcting the scale factor of one of the gyroscopes having a vertical sensitive axis by using data from non-vertical gyroscopes whole scale factors have been corrected. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of providing a special orientation of a gyroscopically oriented survey tool, the method comprising the steps of:
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providing a gyroscopically-oriented survey tool which includes; a housing having an axis; three accelerometers mounted in the housing with their respective sensitive axis set orthogonally, a first of the axis being aligned to the axis of the housing, a second of the axis being perpendicular to the first, and a third of the axis being perpendicular to both of the first axis and the second axis; three gyroscopes mounted pseudo-orthogonally in the housing, the gyroscopes having their respective sensitive axis set at relative angles of other than 90 degrees, none of the axis of the gyroscopes being mounted parallel to the sensitive axis of the accelerometers, such arrangement ensuring that any housing rotation will affect at least two gyroscopes and such arrangement ensuring that any housing rotation about any non-vertical gyroscope axis will affect at least one accelerometer; using corroborating data from the accelerometers to correct offset factors of the gyroscopes; using corroborating data from the accelerometers to correct scale factors of those of the gyroscopes having a non-vertical sensitive axis; and using data from gyroscopes whose scale factors have been corrected to correct the scale factor of one of the gyroscopes having a vertical sensitive axis. - View Dependent Claims (8, 9, 10)
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Specification