Micro hemispherical resonator shows great potential for applications in high-performance gyroscopes. This paper introduces micro hemispherical resonator with teeth-like tines along the edge, aiming at improving mechanical sensitivity of the gyroscope and simplifying the mechanical trimming. The optimized glassblowing resonators with substrate thickness of 200 μm and height near 4.5 mm shows high quality factor, large sensitivity, and balanced electrode gaps. The n = 2 wineglass modes operate at 4.3 kHz, achieving quality factor of 1.18 million and as-fabricated frequency split of 17.8 Hz. After mechanical trimming, the frequency split is reduced below 70 mHz. The vacuum-packaged micro hemispherical resonator gyroscope (mHRG) operating in force-rebalance mode exhibits full-scale range of ±200 deg/sec and bias instability of 0.133 deg/h at room temperature without compensation, indicating that the performance of the gyroscope is limited by the readout electronics. Further improvement is in progress to achieve navigation-grade performance with rate-integrating operation.

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.

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.

Micro hemispherical resonator gyroscopes use a femtosecond laser to remove mass to achieve frequency trimming, which has the advantages of high efficiency and high accuracy. However, the current laser trimming method has the drawback of ablating the capacitance area of the electrode. A novel method for reducing the ablation area of the laser is proposed and demonstrated useful after comparative experiments. Firstly, trimming parameters and propagation process of light is analyzed to reveal the main factor causing the electrode ablation. Then, a novel method using side laser drilling is proposed for reducing the effect of propagation of laser. Trimming process is optimized after researching the effect of ablation shape and angle of the etching triangle. Experiments show that the ablation area fraction of electrode area with gold film can be reduced to 0.2% using optimized process, whereas the ablation area fraction before optimization is more than 10%. Meanwhile, the optimized trimming method can reach a higher trimming accuracy, which can help to improve the gyroscope’s performance.