Identification and compensation method for unbalance error in signal detection chain of Rate-Integrating hemispherical resonator gyro

• Unbalance error model in signal detection chain of RI-HRG is established precisily. • Effect caused by resonator defect is avoided by proposed error identification method. • Performance of RI-HRG is improved significantly after unbalance error compensation. • Compensation accuracy of unbalance error could be further improved through iteration. • Proposed method is suitable for all axisymmetric gyro with Rate-Integrating mode. In this work, a notable effective method is proposed to actualize the identification and compensation for unbalance error in signal detection chain of Rate-Integrating Hemispherical Resonator Gyro (RI-HRG). RI-HRG has excellent dynamic performance and measuring range, which has been verified in multiple field applications. Firstly, the unbalance error model is established with equivalent electrode-misalignment-angle and equivalent relative-chain-gain-deviation, considering about the effect of the inevitable signal coupling, assembly error and electronic components parameter inconsistency error. Then, a high-efficient and high-accuracy identification method is proposed based on the parameter estimation of the free vibration signal envelope, by which the adverse effect of gyro circumferential asymmetry is effectively suppressed. Finally, the compensation method based on feedforward gain controller is designed and implemented with digital control circuit. The experimental results show that the zero bias stability of RI-HRG is improved from 1.0461°/h to 0.0494°/h, which strongly prove the effectiveness of the proposed methods.