High range digital angular rate sensor based on frequency modulation
First Claim
1. A method for operating a Class II Coriolis Vibratory Gyroscope (CVG) comprising:
- producing a frequency modulated (FM) measurement of an input rotation rate which is produced comprising the steps of;
measuring a change in a modal frequency;
ormeasuring a split between two nominally matched modal frequencies,wherein measuring the change in a modal frequency or the split between two nominally matched modal frequencies comprises performing independent frequency counting for each of at least two mechanical modes of vibration of the CVG.
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Abstract
A digital angular rate sensor system based on frequency modulation (FM) of the rotation rate. The new approach relies on tracking of the resonant frequencies of two high-Q mechanical modes of vibration in a MEMS vibratory gyroscope to produce an inherently digital measurement of the input angular rate. The disclosed system is enabled by a combination of a MEMS vibratory high-Q gyroscope and a new signal processing scheme which takes advantage of a previously ignored gyroscope dynamics effect. The FM nature of the system eliminates noise versus bandwidth and resolution versus dynamic range tradeoffs of conventional vibratory rate gyroscopes. The FM approach allows achieving superior signal-to-noise-ratio through the use of ultra-high Q (1 million) mechanical structure without limiting the measurement bandwidth. Stability of 1e-9 can be achieved in the FM system, providing a 1000 times improvement over the state-of-the-art conventional AM gyroscopes with capacitive pick-off.
37 Citations
10 Claims
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1. A method for operating a Class II Coriolis Vibratory Gyroscope (CVG) comprising:
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producing a frequency modulated (FM) measurement of an input rotation rate which is produced comprising the steps of; measuring a change in a modal frequency;
ormeasuring a split between two nominally matched modal frequencies, wherein measuring the change in a modal frequency or the split between two nominally matched modal frequencies comprises performing independent frequency counting for each of at least two mechanical modes of vibration of the CVG. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification