This paper provides an overview of the study of optical resonant cavity stability, focusing on the relevant principles, key technological advances, and applications of optical resonant cavities in a variety of high-precision measurement techniques and modern science and technology. Firstly, the vibration characteristics, thermal noise, and temperature characteristics of the reference cavity are presented. Subsequently, the report extensively discusses the advances in key technologies such as mechanical vibration isolation, thermal noise control, and resistance to temperature fluctuations. These advances not only contribute to the development of theory but also provide innovative solutions for practical applications. Typical applications of optical cavities in areas such as laser gyroscopes, high-precision measurements, and gravitational wave detection are also discussed. Future research directions are envisioned, emphasising the importance of novel material applications, advanced vibration isolation technologies, intelligent temperature control systems, multifunctional integrated optical resonator design, and deepening theoretical models and numerical simulations.

The dither mechanism in a ring laser gyroscope (RLG) produces a lateral deformation when subjected to external acceleration, which is called the g-sensitive misalignment. This article considers the g-sensitive misalignment mechanism, examines the calibration coupling error and the navigation error resulting from it, and proposes a system-level calibration method based on the g-sensitive misalignment. The feasibility of the proposed calibration method is verified by the calibration simulations and experiments using a turntable. The results of a laboratory navigation test and an in-vehicle navigation experiment show that when the g-sensitive misalignment is considered and compensated in the calibration process, the navigation error can be significantly reduced. This article concludes that the g-sensitive misalignment of the RLG should not be disregarded. Finally, it is shown that using an efficient calibration method considering the g-sensitive misalignment can enhance the navigational performance of a high-precision RLG rotational inertial navigation system.

In a high-precision ring laser gyro (RLG) inertial navigation system (INS), the g-sensitive misalignment caused by external acceleration represents one of the main error sources except for the conventional inertial measurement unit (IMU) errors (e.g., gyro drift, accelerometer bias, installation error, and scale factor error) and, thus, cannot be ignored. However, in related literature, there have been no effective suppression methods for the g-sensitive misalignment. To solve this shortcoming, this paper proposes an innovative dual-axis rotation modulation navigation scheme to suppress the velocity and position errors caused by the g-sensitive misalignment, as well as conventional IMU errors. First, an error model of the g-sensitive misalignment is constructed. Then, this model is used to analyze the error propagation law of the g-sensitive misalignment in a conventional dual-axis rotation scheme. Further, based on the error propagation characteristics of each error source, the design principles of rotational modulation schemes are defined. Moreover, a 32-position dual-axis rotational modulation scheme is designed to reduce all errors, including the g-sensitive misalignment in RLG INSs. The effectiveness of the proposed rotation scheme is verified by simulations and experiments. The laboratory experimental results show that the navigation accuracy of the proposed method in this paper is improved by 29.8% and 28.3% compared to the conventional 16-position scheme and 64-position scheme, respectively. The in-vehicle experiments show that the proposed method improves the accuracy by 32.7% over the 64-position scheme. The results indicate that the g-sensitive misalignment suppression is necessary in the RLG INS long-endurance autonomous navigation, and a reasonable rotational modulation scheme can effectively improve navigation accuracy.

The accuracy of the high-precision ring laser gyroscopes is influenced by various factors in the external multi-physics environment, including temperature, mechanical, and magnetic fields. Among them, complex temperature field changes lead to degradation of gyroscope accuracy, limiting application scope. This paper proposes a ring laser gyroscopes bias compensation method based on Gaussian process regression and multi-temperature point measurement configuration. We conduct a laser gyroscope thermal analysis based on internal structure, construct a multi-temperature point measurement configuration that effectively reflects the overall temperature characteristics of the ring laser gyroscope. To solve the non-linear multi-dimensional parameter regression problem in the temperature compensation model, we introduce the Gaussian process regression model for temperature compensation. Validating the proposed method through multiple temperature experiments, the results show it outperforms traditional linear regression models and neural network models for temperature compensation.

In this paper, a rapid alignment method for high-precision rotation inertial navigation system (RINS) within group affine is proposed based on the Lie group theory. The proposed method can effectively solve the ultimate contradiction of initial alignment: speed and accuracy. It meets the requirements of fast response and high accuracy of high-precision RINS. We abandon the conventional coarse alignment + fine alignment scheme and realize a linear Kalman filter alignment method with arbitrarily initial misalignment based on the Earth-centered Earth-fixed frame RINS mechanization and the Lie group theory. Subsequently, considering the error characteristics of RINS two-position alignment, new left-invariant error model and observation model satisfying the group affine property are constructed to improve the convergence speed and accuracy of alignment. It is verified that the method can complete the initial alignment of arbitrary large misalignment and reach the ultimate accuracy in a short time, and the land vehicle navigation test shows that the proposed alignment method can complete the initial alignment of arbitrary misalignment in 5 min under the swaying disturbance and achieve better pure inertial navigation accuracy compared with the traditional scheme.