In recent years, along with the development of new equipment carriers such as unmanned aerial vehicles and unmanned submarine vehicles, inertial navigation systems have generated an urgent demand for gyroscopes that combine high performance with miniaturisation, low cost and lightweight features.With the rapid development of integrated photonics, integrated optical gyroscopes have emerged, and interferometric integrated optical gyroscopes are one of the important ones.This paper outlines the basic working mechanism of IIOG based on the Sagnac effect, and provides a detailed summary of the current research status of interferometric integrated optical gyroscope from two major aspects, namely, the performance enhancement of discrete devices and the integrated coupling package of the system.The main challenges encountered in the current research and applications are analysed, and the future development trend of interferometric integrated optical gyroscopes (IIOGs) is envisioned.

High-precision time and frequency standards are critical for time synchronization and navigation/positioning accuracy in key fields such as global navigation satellite systems (GNSS), transportation systems, power systems, and network systems. Optical atomic clocks exhibit uncertainty metrics two orders of magnitude higher than the current primary standard, the cesium fountain clock, and their adoption for redefining the SI second has been formally proposed. The ytterbium ion optical clock, possessing two clock transition spectrums both adopted as secondary representations of the second, is one of the leading candidate ion systems for the future definition of the second. The ytterbium ion system has significant advantages, including high sensitivity to fundamental physical constants, a high clock transition quality factor, and relatively simplified laser requirements. These characteristics confer substantial potential in fundamental physics research, performance metric enhancement, and engineering applications, gaining widespread attention from research institutions worldwide. This article describes the operating principle of the ytterbium ion optical clock, reviews the key physical effects that constrain the performance of the system and the corresponding suppression methods, summarizes research progresses in fundamental physical exploration, breakthroughs in core performance metrics, and engineering technologies, and discusses prospects for its future development.

In complex underwater environments, multi-source autonomous navigation systems are often adversely affected by environmental interference, its navigation accuracy and robustness decreases. In response to the problem of degraded navigation performance in SINS/DVL/USBL integrated navigation systems under such conditions, a filtering algorithm based on a detectability quantification model is proposed. Firstly, error models are established for the SINS, DVL, and USBL subsystems, and their root mean square errors (RMSE) are calculated as quantitative indices of detectability. Then, an environmental interference factor is introduced to correct the multi-dimensional detectability model, which is constructed by considering coverage, accuracy, real-time performance, and data availability of the sensors. Based on the corrected model, an adaptive filtering algorithm is developed. Finally, the proposed algorithm is validated through test on the Yangtze River. Test results show that the proposed algorithm effectively mitigates the adverse effects of environmental interference on the SINS/DVL/USBL integrated navigation system, with RMSE reductions in the north, east, and vertical directions of 88.5%, 84.0%, and 97.4% compared to the traditional Kalman filtering algorithm, and reductions of 48.3%, 22.6%, and 18.6% compared to the maximum correntropy Kalman filtering algorithm.

Maintenance operations in the “electromagnetic quiet zone” near radio telescopes demand high passive characteristics from navigation systems, rendering conventional navigation methods unsuitable. To address the limitations of traditional methods under passive and low-speed navigation scenarios, a polarization/geomagnetic hybrid orientation method based on BiTAN-UKF is proposed. This method first achieves preliminary nonlinear fusion of polarization navigation and geomagnetic navigation data via UKF, subsequently, by constructing a BiTAN model to capture data time-varying characteristics, it fully leverages the complementarity between the two to enhance orientation accuracy. Experimental results demonstrate that the proposed BiTAN-UKF algorithm achieves orientation accuracy of 0.375 4° in dynamic tests, providing an effective solution for passive navigation requirements in the “electromagnetic quiet zone”.

The marine gravimeter for unmanned small vessels must not only posses excellent dynamic adaptability but also employ a gravity anomaly extraction algorithm capable of effectively filtering non-periodic motion acceleration interference. To addressing these challenges, a gravity data processing method combining forward-backward Kalman filtering with FIR low-pass filtering based on a free-space gravity anomaly state-space model is proposed. Marine gravity measurement experiments are conducted using a small-sized strapdown marine gravimeter with high dynamic adaptability mounted on an unmanned small boat. The test data processing results indicate that compared with direct low-pass filtering method, the combined forward-backward Kalman filtering with FIR low-pass filtering improves accuracy by 48%; compared with forward-backward Kalman filtering method, the accuracy improves by 49%; and compared with traditional Kalman filtering, the accuracy improves by 79%.

Rotational modulation technology is a widely applied error self-compensation technique in inertial navigation systems. Ideal rotational modulation can suppress certain device error components in the orthogonal plane of the rotation axis. However, unavoidable control errors in IMU rotation affect modulation effectiveness. On the one hand, actual rotation control suffers from errors such as angle overshoot. On the other hand, the measurement errors inherent in feedback components such as gratings within the control loop also cause non-uniform rotational angular velocity errors. Based on the consideration of controller and actuator errors, a comprehensive control system model incorporating circular grating measurement errors is established, and the unique influence mechanism of non-uniform rotational angular velocity caused by the feedback control errors of the grating on high-precision azimuth alignment is quantitatively analyzed. Calculation and simulation results show that rotational angle overshoot caused by the controller and actuator has a minor effect on the rotational modulation performance. However, when the circular grating participates in the feedback loop for angle measurement, the resulting non-uniform rotational angular velocity leads to azimuth alignment errors, which cannot be ignored in high-precision inertial navigation systems.

A novel guidance model is proposed for low dynamic unmanned vehicle(UV). Different from traditional guidance model whose state only contains position information, the novel model further incorporates velocity information. For the new guidance model, a new path following algorithm is designed utilizing a control approach based on Lyapunov stability theory. The algorithm consists of proportional + integral limits with saturation constraints, which is simple in form and easy to implement in engineering. Based on stability theory, it is proven that the constructed closed-loop system possesses global asymptotic stability in the presence of model uncertainties and wind field disturbances. To verify the effectiveness of the proposed algorithm, the algorithm is applied as an outer loop in the simulation of path following control of an airship, in which the simulation model is actually used in engineering. Simulation results show that the algorithm exhibits strong robustness and still demonstrates favorable path following performance even under strong wind conditions. Moreover, the guidance algorithm proposed in this paper has better convergence characteristics in simulation compared to an algorithm designed using traditional guidance model.

Regarding the fact that the circularly distributed bias error of HRGs is sensitive to mechanical environments and difficult to test rapidly, the error’s mechanism and manifestation are analysed, the testing method and measurement errors based on acceleration excitation from centrifuges are discussed, and a rapid identification method for acceleration-dependent circularly distributed bias error of HRGs based on driving vibration mode precession is proposed. By driving vibration mode precession in centrifuge test, the circularly distributed bias error under different accelerations is measured without gyro rotation, and the acceleration-dependent error coefficients are obtained by fitting. Experiment results show that this method enables rapid and accurate identification of acceleration-dependent circularly distributed bias error in HRGs, effectively evaluating HRG performance accuracy.

As a critical component of linear displacement sensor, the mover assembly plays a vital role in determining the sensor’s performance and service life. To ensure the sensor delivers more stable output accuracy, higher reliability, and a longer service life, the working principle of the linear displacement sensor and the mover assembly’s key function within the system are firstly analyzed in this paper. Then, the shortcomings of the traditional mover assembly structure are elaborated. A comprehensive optimization of the mover assembly is carried out through a combination of theoretical analysis, numerical simulation, and experimental validation. Simplification and symmetry enhancement of the iron core structure, which improves the sensor’s output accuracy. The optimization and reorganization of the connecting rod assembly structure are carried out, and the combined structure of the iron core and the connecting rod is modified to an embedded structure, which prevents the wear of the iron core during the movement of the mover assembly and improves the output stability of the sensor. The integrated support structure is modified to a rotatable combined support and mover connecting rod structure, which greatly enhances the product’s assembly reliability and service life. The optimized mover assembly structure has improved the output accuracy of the linear displacement sensor by 43.24%, and extended its service life to 60 106 h, providing strong technical support for the further development and application of linear displacement sensor.

The function of capacitance detection circuit of micro electro mechanical system gyroscope is to convert the change of gyro’s sensitive capacitance into voltage that can be processed by digital system. Its performance is one of the important factors affecting gyro accuracy. In order to realize low noise and high performance capacitor-to-voltage circuit, a low noise capacitance detection circuit based on diode envelope demodulation is proposed in this paper. The core circuit consists of a charge sensitive amplifier and a diode envelope demodulation circuit. By analyzing the demodulation mechanism, the filter capacitor resistance and modulation signal range which do not significantly affect the demodulation efficiency are given. Then the noise model is established, the dominant noise parameters are defined, and the noise variation under different parameters is analyzed, in order to optimize that noise of the circuit. Experimental results show that the critical value of the modulated signal is 1.064 V, which is slightly lower than the theoretical value 1.201 V. The error comes from not considering the diode nonlinearity and the harmonic distortion of the readout signal within the critical value does not exceed 0.67%. At the same time, the measured noise voltage spectral density at the gyro operating frequency is -133.6dBV/Hz^1/2, which is in good agreement with the theoretical calculation result.

Redundant sensor configurations can effectively improve the reliability and navigation accuracy of inertial navigation systems(INS). Research on their calibration helps to enhance the actual operational accuracy of inertial measurement unit(IMU). Taking a decuple redundant dual-axis IMU as an example, a universal position arrangement is designed through an internal dual-axis rotation mechanism, the self-calibration consistency of the IMU in different orientations is achieved. Innovatively, the sensors are divided into three groups for system-level self-calibration. An error model for the installation of non-orthogonal sensors is established, along with navigation equations, navigation error equations, and Kalman filtering model. Based on a universal system-level calibration algorithm, a coordinate transformation module is added to calibrate all sensors. Simulation and experiment results show that both the non-orthogonal and orthogonal sensors are calibrated correctly. The calibration algorithm proposed in this paper is clear, easy to implement, and has high engineering application value.

Large-scale constellation networking needs to solve the problems of orbital coordination for thousands of satellites, as well as the efficient networking of inter-satellite links and satellite-to-ground links. In the face of a vast amount of spatial data information, spatial laser communication, as a transmission method with large capacity, strong anti-interference ability, high security and fast communication rate, has become the preferred choice for spatial information transmission. As the core component of laser communication systems, the photoelectric transceiver module plays a significant role in promoting the conversion of optical and electrical signals and improving the quality of signal transmission, and it is the foundation for achieving high-speed and highly reliable laser communication. In order to meet the requirements for an optical communicator that can be used on the space satellite, a fully hermetically sealed butterfly packaged optoelectronic transceiver module is designed. Corresponding anti-radiation optimization designs are carried out in three aspects: light source, software and materials. The optoelectronic transmission performance before and after irradiation is tested, and the irradiation effect results produced by different particles are analyzed. Experiments are conducted using ⁶⁰Co γ-ray radiation and proton radiation as irradiation sources, and a measurement system for radiation field and performance parameter acquisition is built. Data comparison between the anti-radiation module and the traditional module shows that, with the increase of irradiation dose, the optical power and extinction ratio of the traditional module both decrease significantly, while the optical power of the anti-radiation module remains ≥-3 dBm, the extinction ratio still meets ≥4 dB, and the errors are all within the required range. The experimental results demonstrate the stability and good anti-radiation performance of this optoelectronic transceiver module.