Attitude determination and alignment using electro-optical sensors and global navigation satellites
First Claim
1. a method for determining an attitude information for a vehicle, comprising:
- receiving radio-frequency signals from at least two navigation satellites;
applying a filter to determine an expected position of the vehicle and the at least two satellites;
determining an expected angular position and motion of the at least two satellites relative to the vehicle;
measuring an actual angular position and motion of the at least two navigation satellites about two axes relative to the vehicle using an electro-optical sensor; and
computing a difference, along the two axes, between the expected angular position and the rate of the at least two navigation satellites and the measured, actual angular orientation of the vehicle.
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Abstract
An attitude determination and alignment method and system use electro-optical sensors and global navigation satellites to determine attitude knowledge for a spacecraft, satellite, or a high-altitude airborne. An on-board inertial navigation system uses global navigation satellite system equipment and an electro-optical sensor. The electro-optical sensor view the navigation satellites as a surrogate stellar reference sources. The electro-optical sensor replaces the function of a star sensor or tracker and associated processing required for an onboard attitude determination system. Navigation and timing information generated by the GNSS-INS performs required attitude determination system functions.
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Citations
20 Claims
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1. a method for determining an attitude information for a vehicle, comprising:
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receiving radio-frequency signals from at least two navigation satellites;
applying a filter to determine an expected position of the vehicle and the at least two satellites;
determining an expected angular position and motion of the at least two satellites relative to the vehicle;
measuring an actual angular position and motion of the at least two navigation satellites about two axes relative to the vehicle using an electro-optical sensor; and
computing a difference, along the two axes, between the expected angular position and the rate of the at least two navigation satellites and the measured, actual angular orientation of the vehicle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An onboard attitude determination system, comprising:
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an optical sensor receive and focus light energy, including a camera to convert the received light energy into digital electronic data; and
a processor to compare the digital electronic data with received GPS signal data and to determine vehicle attitude from the comparison. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A method for determining an accurate attitude information for a spacecraft, satellite or high-altitude aircraft comprising:
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receiving radio-frequency signals from GPS and other navigation satellites and applying Kalman Filter to determine an expected position of the vehicle;
determining expected angular position and motion of navigation satellites relative to said vehicle equipped by way of a GNSS antenna/receiver unit and an inertial navigation system;
measuring an actual, angular position and motion of the navigation satellites about two axes relative to the vehicle using an onboard electro-optical sensor and an inertial measurement unit;
computing a difference, along two axes, between the expected angular position and the rate of the navigation satellites and the measured, actual angular orientation of the vehicle; and
producing attitude alignment error to the IMU to correct for the instrument drift rate and accumulated alignment error due to drift.
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Specification