Whole-angle gyroscopes have broad prospects for development with inherent advantages of excellent scale factor, wide bandwidth and measurement range, which are restrictions on rate gyroscopes. Previous studies on the whole-angle mode are based mostly on the linear model of Lynch, and the essential nonlinearity of capacitive displacement detection is always neglected, which has significant negative effects on the performance. In this paper, a novel real-time calibration method of capacitive displacement detection is proposed to eliminate these nonlinear effects. This novel method innovatively takes advantage of the relationship between the first and third harmonic components of detective signals for calibration. Based on this method, the real-time calibration of capacitive displacement detection is achieved and solves the problems of traditional methods, which are usually related to the vibration amplitude, environmental variations and other factors. Furthermore, this novel calibration method is embedded into a whole-angle control system to restore the linear capacitive response in real time and then combined with a microshell resonator for the first time to exploit the enormous potential of an ultrahigh Q factor and symmetric structure. The effectiveness is proven because the angle drift is reduced significantly to improve the scale-factor nonlinearity by 14 times to 0.79 ppm with 0.0673°/h bias instability and a 0.001°/s rate threshold, which is the best reported performance of the MEMS whole-angle gyroscope thus far. More importantly, this novel calibration method can be applied for all kinds of resonators with the requirement of a linear capacitive response even under a large resonant amplitude.

The symmetry of the actuation electrode is of great importance for the whole-angle gyroscope. In this paper, the angle drift induced by actuation electrode errors of micro-shell resonator gyroscope is investigated. The actuation electrode errors due to the assembly of the micro-shell resonator and substrate electrode would result in interference effects between the energy and pattern-angle control loops and produce the additional angle drift which has great influences on the performance. The additional angle drift is investigated from experimental and simulation analysis under various actuation gain and angle errors. Furthermore, the characterization and compensation methods of actuation electrode errors are also proposed to eliminate the interference effects of control loops and the additional angle drift. After compensation, the scale-factor nonlinearity and bias instability has been improved by 3 and 2 times to 5.79ppm and 0.064 °/h.

This letter presents a high performance rate-integrating honeycomb disk resonator gyroscope (HDRG). High Q factor resonator and symmetric vibration detection gain are the key to high performance rate-integrating gyroscope. By stiffness-mass decoupling design, HDRG can achieve high Q factor of about 600k and decay time of over 44s. A compensation method is applied to suppress the rate-dependent angular drift caused by the asymmetry circular distribution of detection gains. Finally, the rate-integrating HDRG shows an excellent bias instability of 0.038°/h, 1.05ppm scale factor nonlinearity, wide measurement range of over ±7000°/s and a threshold value of about ±0.0001°/s, which is the best performance in the reported rate-integrating MEMS gyroscopes.

As for the whole-angle gyroscope, the detection symmetry along two axes is of significant importance to improve the gyroscope’s performance. This paper presents the characterization and compensation of detection electrode error for the whole-angle micro-shell resonator gyroscope. The detection electrode errors including detection gain and angle errors mainly result from the assembly process of the micro-shell resonator and substrate electrode. The angle estimation errors, as a direct effect of detection electrode error, are investigated through experiments and theoretical analysis under different detection gain and angle errors. Besides, the consistency of experimental and simulation results proves that the sin and cos components of angle estimation error can be used to characterize detection gain and angle errors respectively. This angle estimation error not only has direct effects on the gyroscope’s angle output but also results in the position error of applied actuation forces. Under this circumstance, the energy control force is observed to interfere with the free precession of the vibration pattern and produces additional angle drift. To eliminate the effects of the detection electrode error, the compensation parameters are identified based on the component analysis of the angle estimation error. After compensation, the bias instability has decreased from 0.118°/h to 0.041°/h and the scale-factor nonlinearity has been also improved by 36 times from 86.57ppm to 2.4ppm. [2021-0176]

The phase error is inevitable in the whole-angle control system and has a great impact on the gyroscope’s performance. In this article, the identification and correction of phase errors are carried out to eliminate the effects of phase errors under the whole-angle mode. The sources of phase errors are analyzed at first from the phase delay of the whole-angle control system. Furthermore, the effects of phase errors are also investigated from the theoretical and experimental analyses. It demonstrates that the phase error would produce coupling effects between the pattern angle and quadrature control loops and produce additional angle drift (AAD) affecting the performance of the whole-angle gyroscope. Therefore, the identification method of phase errors is presented on the basis of the observation of the AAD and the correction of phase errors can also be carried out by the phase shift module. After the correction of phase errors, the performance of bias instability and scale-factor nonlinearity improves by five and nine times, respectively.

With the performance of micromechanical gyroscopes approaching navigation grade, the scale factor nonlinearity is gradually becoming the limitation for high-performance applications such as the satellite attitude measurement. Coupling errors caused by parasitic capacitance are the major sources of scale factor nonlinearity but are usually neglected. In this article, the parasitic-capacitance coupling errors are introduced into the traditional gyroscope model and the scale factor nonlinearity induced by the coupling errors has been analyzed theoretically. The analysis indicates that two parasitic-capacitance couples from sense excitation signal to drive or sense detection signal are the dominant causes of scale factor nonlinearity. Two measurements (i.e., the amplitude of driving excitation signal and axis tuning voltage) are used to realize the calibration of coupling errors with the least square method. The experiment is also carried out to verify this novel calibration method on a navigation-grade honeycomb disk resonator gyroscope. The experimental results demonstrate that the coupling errors have decreased by 87.5 and 44.5 times, respectively, after the error compensation and that the scale factor nonlinearity has been improved from 244.8 ppm to 29.00 ppm. Furthermore, this calibration method can be applied to other resonator gyroscopes with the similar structure and control scheme.