Self calibrating gyroscope system
First Claim
1. A gyroscope system comprising:
- a plurality of gyroscopes, each adapted to sense rate about a respective sense axis, each of said sensed rates exhibiting bias error and scale factor error;
a scale factor error estimator coupled to at least one of said gyroscopes to produce an estimate of scale factor error of such coupled ones of said gyroscopes;
a mode reversal unit coupled to such coupled ones of said gyroscopes to produce an estimate of bias error of such coupled ones of said gyroscopes; and
a compensator responsive to sensed rates of such coupled ones of said gyroscopes, said bias error estimate, and said scale factor error estimate to produce rate outputs for such coupled ones of said gyroscopes;
said rate outputs exhibiting reduced bias error and reduced scale factor error as compared to bias error and scale factor error of corresponding rates sensed by such coupled ones of said gyroscopes wherein said coupled ones of said gyroscopes has a resonator exhibiting a pattern of standing waves having an orientation, wherein an expected position of the pattern and a measured position of the pattern is used to determine a scale factor error of the gyroscope.
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Abstract
A self-calibrating gyroscope system provides improved estimates of, and compensation or calibration for, scale factor errors and bias errors. The gyroscope system employs a plurality of gyroscope units having sense or input axes in a mutually non-parallel arrangement. A Mode Reversal technique is used to obtain an estimate of bias error for a selected gyroscope. A Random Closed-Loop Scale Factor technique is used to obtain an estimate of scale factor error for a selected gyroscope. Because the Mode Reversal technique temporarily disrupts operation of the affected gyroscope, each of the gyroscopes may be taken offline temporarily, in turn, for calibration, and thereafter returned to normal operation. Because at least one redundant gyroscope is provided, when a selected gyroscope is offline, rate information from the remaining operating gyroscopes can be used to derive a reference rate about the axis of the offline gyroscope.
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Citations
24 Claims
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1. A gyroscope system comprising:
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a plurality of gyroscopes, each adapted to sense rate about a respective sense axis, each of said sensed rates exhibiting bias error and scale factor error; a scale factor error estimator coupled to at least one of said gyroscopes to produce an estimate of scale factor error of such coupled ones of said gyroscopes; a mode reversal unit coupled to such coupled ones of said gyroscopes to produce an estimate of bias error of such coupled ones of said gyroscopes; and a compensator responsive to sensed rates of such coupled ones of said gyroscopes, said bias error estimate, and said scale factor error estimate to produce rate outputs for such coupled ones of said gyroscopes; said rate outputs exhibiting reduced bias error and reduced scale factor error as compared to bias error and scale factor error of corresponding rates sensed by such coupled ones of said gyroscopes wherein said coupled ones of said gyroscopes has a resonator exhibiting a pattern of standing waves having an orientation, wherein an expected position of the pattern and a measured position of the pattern is used to determine a scale factor error of the gyroscope. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A gyroscope system comprising:
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a plurality of gyroscopes; a controller coupled to the plurality of gyroscopes; said controller having; a rate error compensator responsive to at least an uncompensated gyroscope rate signal of a gyroscope for producing a compensated gyroscope rate signal wherein the gyroscope has a resonator exhibiting a pattern of standing waves having an orientation, wherein an expected position of the pattern and a measured position of the pattern is used to determine a scale factor error of the gyroscope. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of operating a gyroscope system having a plurality of gyroscopes, comprising:
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operating the gyroscope system wherein each of the plurality of gyroscopes is adapted to sense rate about a respective axis, each of said rates exhibiting bias error and scale factor error, selecting one gyroscope for calibration; taking the selected gyroscope offline; determining an estimate of bias error of said selected gyroscope; determining an estimate of scale factor error of said selected gyroscope wherein said selected gyroscope has a resonator exhibiting a pattern of standing waves having an orientation, wherein an expected position of the pattern and a measured position of the pattern is used to determine a scale factor error of the gyroscope; compensating a rate output of said selected gyroscope with said bias error estimate and scale factor error estimate; and returning said selected gyroscope online. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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Specification