Azimuth determination system and method therefor
First Claim
1. An azimuth determination system comprising:
- a platform;
a plurality of gimbals attached to the platform to allow the platform to rotate about multiple axes;
a pair of gryos attached to the platform;
a leveling device attached to the platform to indicate when the platform is at a desired position;
a control device attached to the plurality of gimbals to move the platform to the desired position indicated by the leveling device; and
an electronics system to provide power to the azimuth determination system and to determine azimuth by positioning the gyros in a first position with an input axis of the gyros orthogonal to the Earth Rate vector to calculate a first output and rotating the gyros 180°
about the vertical to a second position to calculate a second output, the platform inverted and rotated to calculate a third and fourth outputs, wherein the four outputs are combined to produce the azimuth value and gyro induced bias error.
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Accused Products
Abstract
An azimuth determination system has a platform. A plurality of gimbals is attached to the platform to allow the platform to rotate about multiple axes. A pair of gryos is attached to the platform. A leveling device is attached to the platform to indicate when the platform is at a desired position. A control device attached to the plurality of gimbals to move the platform to the desired position indicated by the leveling device. An electronics system is to provide power to the azimuth determination system and to determine azimuth by positioning the gyros in a first position with an input axis of the gyros in the horizontal plane and orthogonal to the Earth Rate vector to calculate a first output and rotating the gyros 180° about the vertical to a second position to calculate a second output, the platform is then inverted and an additional set of two readings is taken. The four outputs are combined to produce the azimuth value and a gyro induced bias error. The azimuth value of the autocollimator line of sight is transferred to the laboratory reference mirror.
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Citations
20 Claims
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1. An azimuth determination system comprising:
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a platform; a plurality of gimbals attached to the platform to allow the platform to rotate about multiple axes; a pair of gryos attached to the platform; a leveling device attached to the platform to indicate when the platform is at a desired position; a control device attached to the plurality of gimbals to move the platform to the desired position indicated by the leveling device; and an electronics system to provide power to the azimuth determination system and to determine azimuth by positioning the gyros in a first position with an input axis of the gyros orthogonal to the Earth Rate vector to calculate a first output and rotating the gyros 180°
about the vertical to a second position to calculate a second output, the platform inverted and rotated to calculate a third and fourth outputs, wherein the four outputs are combined to produce the azimuth value and gyro induced bias error. - View Dependent Claims (2, 3, 4, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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5. An azimuth determination system in accordance with claim further comprising a rotary table attached to the platform, the rotary table limited to rotating approximately ±
- 90°
to reduce noise.
- 90°
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6. An azimuth determination system in accordance with claim further comprising proximity electronics attached to the platform.
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16. An azimuth determination system comprising:
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a rotary table; a platform; a heat exchanger positioned between the platform and the rotary table; proximity electronics attached to the platform; a plurality of gimbals attached to the platform to allow the platform to rotate about multiple axes; a pair of gryos attached to the platform; at least one heating device positioned on each gyro to control a temperature of each gyro; a plurality of end caps, wherein one end cap is placed on each end of each gyro with heating devices for thermal control; a trunnion heating device placed on each platform gimbal trunnion; a leveling device attached to the platform to indicate when the platform is at a desired position, wherein the leveling device has a covering to minimize thermal gradients and temperature variations. - View Dependent Claims (17, 18)
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19. A gyrocompassing method to calculate azimuth free of gyro induced bias error comprising:
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positioning a pair of gyros in a first position with an input axis of the gyros orthogonal to the Earth Rate vector to calculate a first output; rotating the gyros 180°
about the vertical to a second position to calculate a second output; anda control device attached to the plurality of gimbals to move the platform to the desired position indicated by the leveling device, wherein the control device comprises; a first motor to bring an inner gimbal of the plurality of gimbals to a desired position; and a second motor to move the platform to the desired position indicated by the leveling device; and an electronics system to provide power to the azimuth determination system and to determine azimuth by positioning the gyros in a first position with an input axis of the gyros in the horizontal plane and orthogonal to the Earth Rate vector to calculate a first output and rotating the gyros 180°
about the vertical to a second position to calculate a second output, the platform is inverted and an additional set of two readings is taken, wherein the four outputs are combined to produce the azimuth value and a gyro induced bias error;calculating the azimuth, the azimuth equal to Sine−
1(First Output−
Second Output)/2ω
ie-h, wherein ω
ie-h is the horizontal component of earth rate. - View Dependent Claims (20)
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Specification