Time-interleaved analog-to-digital converter (TI-ADC) technology can increase the sampling rate without changing resolution. But, the dynamic performance of TI-ADC system is seriously deteriorated by channel mismatches. Under the condition of large bandwidth, gain mismatch and timing mismatch vary with the frequency, which cannot be regarded as fixed values. To improve the dynamic performance of the TI-ADC system, an automatic calibration method of channel mismatches for wideband TI-ADC system is proposed in this article. Frequency-dependent channel mismatches are estimated by the algorithm based on sine fitting, and compensated by the means based on perfect reconstruction. The entire sampling and calculation process is automated and tedious operation is simplified. A 6.8-GS/s 12-bit wideband TI-ADC system is implemented. This sampling system can achieve SNDR (signal-to-noise and distortion ratio) above 49 dB and SFDR (spurious-free dynamic range) above 57 dB for an input signal from 100 MHz to 3300 MHz. The proposed calibration method improves the SNDR over 10 dB and the SFDR over 15 dB. The dynamic performance of the sampling system is close to that of its sub-ADC.

Damping mismatch, detection error, and actuation error are the primary sources of the output drift in rate-integrating hemispherical resonator gyroscopes (HRGs). To date, separating the three errors remains a challenge, which hinders the accurate compensation of HRGs. This article proposes a novel method to separate the damping, detection, and actuation errors of HRGs. Theoretically, a dynamics model of HRGs considering the three errors is developed, where the detection and actuation errors are modeled using Fourier analysis. The effects of these three errors on the scale factor and the bias under different operation modes are discussed in detail for the first time. It is found that the three errors can be decoupled under the decay with quadrature control (DQC) mode, a special operation mode designed in this article. In the experiments, by measuring the angle dependence of the scale factor and the bias of the energy loop, the damping, detection, and actuation errors of three HRGs are successfully identified and then comprehensively compensated. For one typical tested HRG, after compensation, the angle-dependent error of the scale factor decreases from 1.08% to 0.036% by a factor of 30, the angle-dependent variation of the static drift reduces from $5.14 \times 10^{-3} \; ^{\circ }$ /s to $2.37 \times 10^{-4} \; ^{\circ }$ /s by a factor of 22, and the fluctuation of the dynamic output at different input rates decreases 14–25 times. Our method can also be conveniently applied to other rate-integrating Coriolis vibrating gyroscopes (CVGs).

Detection signal nonlinearity, induced by nonlinear capacitive variations in electrode gaps, fundamentally limits the performance of whole-angle (WA) mode hemispherical resonator gyroscopes (HRGs). This letter proposes a rapid identification method for this nonlinearity based on the relationship between the amplitude-gap ratio and resonator vibration energy. Experimental results across 100-500 °/s input rotation velocities confirms method accuracy and operational robustness. Post-compensation HRG achieves a bias instability (BI) of 0.006 °/h and a scale factor nonlinearity (SFN) of 0.08 ppm. The achieved SFN of 0.08 ppm represents the lowest reported value for WA mode HRGs to date.

The damping asymmetry, the phase delay and the electrode errors are crucial factors that limit the performance of hemispherical resonator gyroscopes. This paper employs mode reversal to compensate for damping asymmetry. A mathematical model is first established incorporating the stiffness asymmetry, the damping asymmetry, the phase delay and the electrode errors. The influences of the phase delay and the electrode errors on mode-reversal force-to-rebalance hemispherical resonator gyroscopes are analyzed, respectively. New methods to identify the phase delay and the electrode errors are proposed, which eliminate the influences of both the control-loop couplings and the couplings among different error sources. Experimental results demonstrate that the angle-dependent bias in the turntable-rotation mode is reduced from 3.72 °/s to 0.02 °/s after the compensation of detection electrode errors, demonstrating a decrease of 99.5%; the angle-dependent bias in the virtual-rotation mode is reduced from 0.107 °/s to 0.006 °/s after the compensation of actuation electrode errors, demonstrating a decrease of 94.4%. After compensation, the bias instability of the mode-reversal force-to-rebalance hemispherical resonator gyroscope is improved from 0.046 °/h to 0.003 °/h, demonstrating an improvement of 93.5%. The proposed methods can be widely applied to Coriolis vibratory gyroscopes with symmetric structures operating in both the force-to-rebalance mode and the whole-angle mode.

Hemispherical resonator gyroscopes (HRGs) exhibit exceptional force-to-rebalance (FTR) precision but suffer from temperature-dependent drift, limiting widespread deployment. This study presents a temperature-dependent bias drift compensation method for HRGs using a dual-HRG system configuration. The dual-HRG system compensates for temperature-dependent bias drift based on mode reversal. By implementing alternating mode-reversal control sequences between two HRGs, the dual-HRG system overcomes the limitations of single HRG mode reversal in practical applications. Furthermore, based on the calibration results of phase delay errors, electrode errors and scale factors (SFs) at different temperatures, corresponding temperature compensation modules are incorporated into the dual-HRG system. The residual temperature-dependent bias drift is further compensated by applying the multiple regression algorithm. Experimental results demonstrate that the bias stability of the dual-HRG system after mode reversal is improved by more than 98.7% and 87.7% compared to the two individual HRGs, respectively. Moreover, the temperature-dependent bias drift is further compensated by the multiple regression algorithm, and the bias stability of the dual-HRG system is improved by more than 70.5%.

A cylindrical resonator gyroscope is a kind of Coriolis gyroscope, which measures angular velocity or angle via processing of the standing wave. The symmetry of a cylindrical resonator is destroyed by different degrees of geometric nonuniformity and structural damage in the machining process. The uneven mass distribution caused by the asymmetry of the resonator can be expressed in the form of a Fourier series. The first three harmonics will reduce the anti-interference ability of the resonator to the external vibration, as well as increase the angular random walk and zero-bias drift of the gyroscope. In this paper, the frequency split of different modes caused by the first three harmonic errors and the displacement of the center of the cylindrical resonator bottom plate are obtained by simulation, and the relationship between them is explored. The experimental results on five fused silica cylindrical resonators are consistent with the simulation, confirming the linear relationship between the n = 1 frequency split and second harmonic error. A method for evaluating the first three harmonic errors of fused silica cylindrical resonators is provided.