Optic Gyroscope Research Articles

Detection Method of Resonant Fiber Optic Gyroscope With Hollow-Core Photonic Crystal Fiber Based on Phase-Shift Keying Modulation

Detection Method of Resonant Fiber Optic Gyroscope With Hollow-Core Photonic Crystal Fiber Based on Phase-Shift Keying Modulation

A Fusion Algorithm for Real-Time Temperature Compensation and Noise Suppression With a Double U-Beam Vibration Ring Gyroscope

A Fusion Algorithm for Real-Time Temperature Compensation and Noise Suppression With a Double U-Beam Vibration Ring Gyroscope

Comparative analysis of local angular rotation between the ring laser gyroscope GINGERINO and GNSS stations

Comparative analysis of local angular rotation between the ring laser gyroscope GINGERINO and GNSS stations

Temperature error compensation method of fiber optic gyroscope based on deep learning

This work provides an error compensation strategy based on deep learning to address the temperature error of a fiber optic gyroscope (FOG). The Attention structure was used to improve the Long Short-Term Memory Network (LSTM), and the improved network was utilized to establish the prediction and compensation model of FOG error. From the two perspectives of the learning ability of the neural network and the improvement of FOG performance, this paper selects three indicators: prediction accuracy, mean square error, and FOG bias stability to comprehensively evaluate the performance of the compensation model. Through comparison, the compensation effect is significantly enhanced.

Possible Tests of Fundamental Physics with GINGER

The GINGER (gyroscopes in general relativity) project foresees the construction of an array of large frame ring laser gyroscopes, rigidly connected to the Earth. Large frame ring laser gyroscopes are high-sensitivity instruments used to measure angular velocity with respect to the local inertial frame. In particular, they can provide sub-daily variations in the Earth rotation rate, a measurement relevant for geodesy and for fundamental physics at the same time. Sensitivity is the key point in determining the relevance of this instrument for fundamental science. The most recent progress in sensitivity evaluation, obtained on a ring laser prototype, indicates that GINGER should reach the level of 1 part in 1011 of the Earth’s rotation rate. The impact on fundamental physics of this kind of apparatus is reviewed.

Design and analysis of a freeform surface lens coupler applied in hollow‐core photonic crystal fiber resonant optic gyros

AbstractIn this study, a novel freeform surface lens coupler is designed to realize the coupling functions in the hollow‐core photonic crystal fiber (HCPCF) resonator optical gyroscope. One surface of the lens is an ellipsoid. Coupling of the two HCPCF loop's ports can be directly accomplished via reflection on the ellipsoid surface. The other surface of the lens is the Biconic Zernike surface. Transmitting through the above two surfaces, the coupling between the intracavity and extracavity is completed. In this paper, simulations were performed based on two types of HCPCFs, a hollow‐core photonic bandgap fiber of HC19‐1550 and a state‐of‐the‐art nested antiresonant nodeless fiber. The volume of the lens coupler is calculated to be approximately 4 × 2 × 4 mm3. The simulation results show that the intracavity coupling loss can be as low as 0.011 dB, and the coupling loss between the intracavity and extracavity can be as low as 0.4 dB. Compared with the traditional fusion scheme between hollow‐core fiber and polarization‐maintaining fiber, the freeform surface lens coupler in this paper can achieve lower coupling loss and higher resonance fineness. Compared with other spatial coupling schemes, it has lower coupling loss and fewer coupling components.

GINGERINO: a high sensitivity ring laser gyroscope for fundamental and quantum physics investigation

Ring Laser Gyroscopes, based on the Sagnac effect, are currently the most sensitive rotation sensors. GINGERINO, a RLG installed underground, shows a proved sensitivity that enters the few frad/s regime in about 2.5 days of integration time. On one hand, this sensitivity is well below the shot–noise–level as predicted applying to GINGERINO the so called independent beam model. On the other hand, it paves the way to the use of RLG in fundamental and quantum physics research. Indeed, high sensitivity rotation measurement opens to test general relativity and alternative theory of gravity. Moreover, it make possible to study the interplay between quantum effects in the optical domain and non-inertial reference frames.

A self-calibration method for temperature errors of non-orthogonal angles between gimbals in rotational inertial navigation system

The rotational inertial navigation system (RINS) employs a rotating modulation technique by introducing rotation gimbals, thereby enhancing accuracy of the RINS in position and velocity estimation. Furthermore, the rotation gimbals provide the self-calibration ability in the RINS. However, it introduces new sources of error, such as non-orthogonal angles between gimbals, which result in inaccuracies in attitude outputs and thus require precise calibration and compensation. Previous research has largely overlooked the influence of temperature on non-orthogonal angles and the calibration accuracy are susceptible to various factors. In this paper, we discuss the causes of temperature-induced errors in non-orthogonal angles and their impact on attitude estimation, and a self-calibration method based on outputs from fiber optic gyroscopes and optical angle encoders is proposed, showing good repeatability by using periodic averaging. The rapid rotation scheme adopted is suitable for calibrating temperature errors during system operation and a temperature-stabilized chamber is not required. The results of navigation experiments validate the effectiveness of the calibration and compensation method. After compensating the temperature errors of non-orthogonal angles, we can see a decrease in the amplitude of attitude output oscillation from 80″ to less than 10″.

CEEMDAN-LWT De-Noising Method for Pipe-Jacking Inertial Guidance System Based on Fiber Optic Gyroscope.

An inertial guidance system based on a fiber optic gyroscope (FOG) is an effective way to guide long-distance curved pipe jacking. However, environmental disturbances such as vibration, electromagnetism, and temperature will cause the FOG signal to generate significant random noise. The random noise will overwhelm the effective signal. Therefore, it is necessary to eliminate the random noise. This study proposes a hybrid de-noising method, namely complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN)-lifting wavelet transform (LWT). Firstly, the FOG signal is extracted using a sliding window and decomposed by CEEMDAN to obtain the intrinsic modal function (IMF) with N different scales and one residual. Subsequently, the effective IMF components are selected according to the correlation coefficient between the IMF components and the FOG signal. Due to the low resolution of the CEEMDAN method for high-frequency components, the selected high-frequency IMF components are decomposed with lifting wavelet transform to increase the resolution of the signal. The detailed signals of the LWT decomposition are de-noised using the soft threshold de-noising method, and then the signal is reconstructed. Finally, pipe-jacking dynamic and environmental interference experiments were conducted to verify the effectiveness of the CEEMDAN-LWT de-noising method. The de-noising effect of the proposed method was evaluated by SNR, RMSE, and Deviation and compared with the CEEMDAN and LWT de-noising methods. The results show that the CEEMDAN-LWT de-noising method has the best de-noising effect with good adaptivity and high accuracy. The navigation results of the pipe-jacking attitude before and after de-noising were compared and analyzed in the environmental interference experiment. The results show that the absolute error of the pipe-jacking pitch, roll, and heading angles is reduced by 39.86%, 59.45%, and 14.29% after de-noising. The maximum relative error of the pitch angle is improved from -0.74% to -0.44%, the roll angle is improved from 2.07% to 0.79%, and the heading angle is improved from -0.07% to -0.06%. Therefore, the CEEMDAN-LWT method can effectively suppress the random errors of the FOG signal caused by the environment and improve the measurement accuracy of the pipe-jacking attitude.

Theoretical thermoelastic damping for micro ring gyroscopes by wave propagation

The microelectromechanical system (MEMS) vibrating ring gyroscope (VRG) holds significant promise for angle sensing applications, with its performance highly reliant on the thermoelastic damping (TED) of the resonating structure. However, the existing TED models struggle to accommodate the complex topology of VRGs. In this study, the wave propagation method is introduced to establish a theoretical TED model for in-plane motion VRGs. The modeling entails a comprehensive analysis of the thermoelastic coupling within the VRG structure, considering the displacement and the coupled temperature field. Treating VRG as a cyclic symmetric structure, the displacement and temperature fields within the minimum repetitive sector can be analyzed first and then extrapolated to the entire structure. The mode shape, natural frequency and temperature variation of the VRG are determined using the wave propagation method. Finally, The TED expression is obtained based on its energy definition. Comparisons with FEM and experimental results demonstrate the high accuracy, computational efficiency and versatility of the present TED model. Parametric analysis reveals that TED in VRGs is determined collectively by the TED of their substructures, with the influence weights depending on their respective strain energy proportions. Specifically, increasing the length and decreasing the width of the substructure, or scaling down the overall size can effectively reduce TED in most cases. VRGs with a larger width are not recommended due to their high TED value and complex TED behavior. Additionally, VRG's TED is predicted to increase rapidly with rising ambient temperature due to the temperature dependence of material properties. This study presents an efficient TED modeling method for complex ring-beam combined structures and offers practical guidelines for designing high Q-factor VRGs.

A Polarization Multiplexing Interferometric Fiber Optic Gyroscope With Faraday Effect and Shupe Effect Compensation

A Polarization Multiplexing Interferometric Fiber Optic Gyroscope With Faraday Effect and Shupe Effect Compensation

Image stabilization technology based on inertial sensors and piezoelectric fast pendulum mirrors

Aiming at the interferences caused by vibrations on the target monitoring system of satellite platforms, an experimental system of optical–mechanical–electrical joint image stabilization based on inertial sensors and piezoelectric fast mirrors was studied. First of all, the data from the fiber optic gyroscope and the detector are combined and processed. After that, the predicted intentional velocity is subtracted from the real-time gyroscope data, and the vibration displacement is obtained using an integral. The feedback amount is calculated using the processor according to the vibration displacement, the piezoelectric fast mirror is controlled to compensate the vibration interferences, and the purpose of stabilizing the images is achieved. The experimental results show that under a vibration interference of 300μrad/s, the image stabilization control frequency of the system reaches 500 Hz, the relative error between image frames is better than 3μrad, and the intra-frame stabilization performance of the detector meets the requirements on stabilized image and target detection for space targets on the star-carrying platform.

A Low-Cost and High-Precision Underwater Integrated Navigation System

The traditional underwater integrated navigation system is based on an optical fiber gyroscope and Doppler Velocity Log, which is high-precision but also expensive, heavy, bulky and difficult to adapt to the development requirements of AUV swarm, intelligence and miniaturization. This paper proposes a low-cost, light-weight, small-volume and low-computation underwater integrated navigation system based on MEMS IMU/DVL/USBL. First, according to the motion formula of AUV, a five-dimensional state equation of the system was established, whose dimension was far less than that of the traditional. Second, the main source of error was considered. As the velocity observation value of the system, the velocity measured by DVL eliminated the scale error and lever arm error. As the position observation value of the system, the position measured by USBL eliminated the lever arm error. Third, to solve the issue of inconsistent observation frequencies between DVL and USBL, a sequential filter was proposed to update the extended Kalman filter. Finally, through selecting the sensor equipment and conducting two lake experiments with total voyages of 5.02 km and 3.2 km, respectively, the correctness and practicality of the system were confirmed by the results. By comparing the output of the integrated navigation system and the data of RTK GPS, the average position error was 4.12 m, the maximum position error was 8.53 m, the average velocity error was 0.027 m/s and the average yaw error was 1.41°, whose precision is as high as that of an optical fiber gyroscope and Doppler Velocity Log integrated navigation system, but the price is less than half of that. The experimental results show that the proposed underwater integrated navigation system could realize the high-precision and long-term navigation of AUV in the designated area, which had great potential for both military and civilian applications.

Brillouin lasing in microspheres coupled with silicon subwavelength grating waveguides

Brillouin lasing has been widely applied to microwave oscillators, optical gyroscopes, optical sensors, and other fields owing to its strong and flexible dynamics. Microspheres with ultrahigh quality factors and small mode volume are very suitable for generating Brillouin lasing, but it is difficult to integrate them on a chip. Here, we utilize subwavelength grating waveguide as a photonic coupler to connect the silica microsphere with a silicon chip and realize on-chip backward Brillouin lasing. It is experimentally indicated that when the on-chip pump power reaches 24.8 mW, the backward Brillouin lasing with an on-chip slope efficiency of 5% will be excited. Our method makes it easier to realize on-chip Brillouin acousto-optic interaction and greatly expands the application range of microspheres.

Anti-PT-Symmetric Optical Gyroscope at the Transmission Peak Degeneracy With Enhanced Signal-to-Noise Ratio

Anti-PT-Symmetric Optical Gyroscope at the Transmission Peak Degeneracy With Enhanced Signal-to-Noise Ratio

Dual closed-loop control method for resonant integrated optic gyroscopes with combination differential modulation

In order to optimize the detection accuracy and output stability of Resonant Integrated Optic Gyroscopes (RIOG), a dual closed-loop control method for combined differential modulation (DCM Control) has been proposed. Two optical signals are differentially modulated in sync, and their differential-mode output results are compensated in real-time. Considering the distinct characteristics of the two frequency servo loops, they are respectively utilized to tune the laser frequency to track the resonant frequency's wide fluctuations and continuously changing resonant frequency due to random rotation. Through this novel structure, we have enhanced reciprocity while reducing optical components, suppressing RIM noise and laser frequency noise in the gyroscope system, and effectively reducing control errors. We analyze the principles affecting angular velocity detection accuracy and the system's output model. Experimental results indicate that this method can effectively achieve high reciprocity and high-precision frequency control, offering a larger dynamic detection range and better linearity. The long-term bias instability (BI) based on Allan deviation is measured at 0.95°/h, and the angle random walk (ARW) is 0.119°/√h, providing a simple and efficient approach for RIOG closed-loop signal processing.

A Segmented Cross-Correlation Algorithm for Dynamic North Finding Using Fiber Optic Gyroscopes.

Fiber optic gyroscope (FOG)-based north finding is extensively applied in navigation, positioning, and various fields. In dynamic north finding, an accelerated turntable speed shortens the time required for north finding, resulting in a rapid north-finding response. However, with an increase in turntable speed, the turntable's jitter contributes to signal contamination in the FOG, leading to a deterioration in north-finding accuracy. This paper introduces a divide-and-conquer algorithm, the segmented cross-correlation algorithm, designed to mitigate the impact of turntable speed jitter. A model for north-finding error is established and analyzed, incorporating FOG's self-noise and the turntable's speed jitter. To validate the feasibility of our method, we implemented the algorithm on a FOG. The simulation and experimental results exhibited a strong concordance, affirming the validity of our proposed north-finding error model. The experimental findings indicate that, at a turntable speed of 180°/s, the north-finding bias error within a 360 s duration is 0.052°, representing a 64% improvement over the traditional algorithm. These results indicate the effectiveness of the proposed algorithm in mitigating the impact of unstable turntable speeds, offering a solution for north finding with both prompt response and enhanced accuracy.

Investigation of rotational motion in a reinforced concrete frame construction by a fiber optic gyroscope

Investigation of rotational motion in a reinforced concrete frame construction by a fiber optic gyroscope

New Application and Research of Ring Laser Gyroscope in the Field of Angle Metrology

New Application and Research of Ring Laser Gyroscope in the Field of Angle Metrology

Research on the Influence of Biased Structure in Hybrid Inertial Navigation System Based on Rate Biased Ring Laser Gyroscope

Research on the Influence of Biased Structure in Hybrid Inertial Navigation System Based on Rate Biased Ring Laser Gyroscope