Angular Random Walk Estimation of a Time-Domain Switching Micromachined Gyroscope

Microelectromechanical systems MEMS gyroscopes could potentially be used in low cost, size, weight, and power CSWaP navigation-grade inertial navigation units, but current solutions cannot be used due to issues with angular random walk ARW, bias instability, and scale factor instability. While there are methods to address issues with bias and scale factor instability, with the commonly used demodulation schemes, ARW is limited by the ability to produce resonators with very high quality factors. Given that producing resonators with very high quality factors is challenging, the time-domain switching micromachined gyroscope TDSMG is proposed. As opposed to the conventional means that employ electrostatic sensing, the motion of the proof mass is detected through switches at known locations. In conjunction with an accurate time interval analyzer, the TDSMG is capable of estimating rotation rate in a low-noise fashion that is robust to environmental effects. Thus, it is expected that it will have low bias and scale factor instabilities. Simulated ARW performance of a particular incarnation of the TDSMG is studied. It is found that with narrow-bandwidth restrictions, near navigation-grade performance is capable without the need for the resonator to have a very high quality factor.