Patent ID: 9157739
Filing Date: 2015-10-13
Classification: G01C

Abstract:
1. An axisymmetrical Coriolis Vibrating Gyroscope (CVG) system, comprising: a first gyroscope having an axisymmetrical resonator; a plurality of actuators mounted on the resonator to drive first and second vibration modes, the second vibration mode being sensitive to Coriolis forces, wherein the second vibration mode is offset from the first vibration mode by 45°; a plurality of sensor elements mounted on the resonator to sense the first vibration mode and the second vibration mode; and a second gyroscope with a coaxial sensitive axis and configured to provide a measurement of angular velocity while the first gyroscope is in a transition phase, wherein an excitation signal is alternately used to drive the first vibration mode and to drive an excitation of the second vibration mode over a period of time; and a switch configured to change a sign of the measured angular velocity when the excitation of the first vibration mode changes to the excitation of the second vibration mode, and an orientation of a sensitive axis of the CVG rotates by 180 degrees when comparing an orientation of the sensitive axis when the excitation of the first vibration mode changes to the excitation of the second vibration mode; and wherein the switch is configured so that a sign of a zero-bias output of the CVG does not change when the excitation of the first vibration mode changes to the excitation of the second vibration mode, wherein the switch configures the gyroscopes to have a time interval of the transition for the first gyroscope to be the same as a time interval of the transition of the second gyroscope, wherein bias errors of the first gyroscope are eliminated over an entire range of θ representing angular orientation of a vibration axis of the first vibration mode relative to an axis for excitation of a first electrode of the first gyroscope, and wherein the switch is configured so that scale factors of the first gyroscope when exciting the first and second vibration modes are calibrated to be equivalent.