Gyro Output Research Articles

Resonator fiber optic gyro employing a semiconductor laser

Resonator fiber optic gyro (RFOG) based on the Sagnac effect has the potential to achieve the inertial navigation system requirement with a short sensing coil. Semiconductor laser is one of the key elements for integration and miniaturization of the RFOG. In this paper, an RFOG employing a semiconductor laser is demonstrated. The model of the laser frequency noise induced error in the RFOG is described. To attenuate the laser frequency noise induced error, active frequency stabilization is applied. An online laser frequency noise observation is built, as a powerful optimum criterion for the loop parameters. Moreover, the laser frequency noise observation method is developed as a new measurement tool. With a fast digital proportional integrator based on a single field programmable gate array applied in the active stabilization loop, the laser frequency noise is reduced to 0.021 Hz (1σ). It is equivalent to a rotation rate of 0.07°/h, and close to the shot noise limit for the RFOG. As a result, a bias stability of open-loop gyro output is 9.5°/h (1σ) for the integration time 10 s in an hour observed in the RFOG. To the best of our knowledge, this result is the best long-term stability using the miniature semiconductor laser.

Detection of (In)activity Periods in Human Body Motion Using Inertial Sensors: A Comparative Study

Determination of (in)activity periods when monitoring human body motion is a mandatory preprocessing step in all human inertial navigation and position analysis applications. Distinction of (in)activity needs to be established in order to allow the system to recompute the calibration parameters of the inertial sensors as well as the Zero Velocity Updates (ZUPT) of inertial navigation. The periodical recomputation of these parameters allows the application to maintain a constant degree of precision. This work presents a comparative study among different well known inertial magnitude-based detectors and proposes a new approach by applying spectrum-based detectors and memory-based detectors. A robust statistical comparison is carried out by the use of an accelerometer and angular rate signal synthesizer that mimics the output of accelerometers and gyroscopes when subjects are performing basic activities of daily life. Theoretical results are verified by testing the algorithms over signals gathered using an Inertial Measurement Unit (IMU). Detection accuracy rates of up to 97% are achieved.

Selection of the Series Compensation Parameters for a Closed Loop, Rotor Vibratory Gyroscope

This article presents an approach to the selection of the Series Compensation (SC) parameters for a Rotor Vibratory Gyroscope in closed loop operation (RVG), to meet the necessary quality of dynamical and statical characteristics of such a gyroscope output. The proposed approach is based on a mathematical model of a RVG as a two axis control system with modulation. The analysis of this model allows us to reveal some peculiarities of the system, for instance, the effect of “limited quality factor.” The influence of these observed peculiarities on the dynamical and statical characteristics of a RVG are studied and reflected in the proposed approach. Finally, the selection of the SC parameters is illustrated with a commercially available RVG.

Dynamic characteristics of resonant gyroscopes study based on the Mathieu equation approximate solution

Dynamic characteristics of the resonant gyroscope are studied based on the Mathieu equation approximate solution in this paper. The Mathieu equation is used to analyze the parametric resonant characteristics and the approximate output of the resonant gyroscope. The method of small parameter perturbation is used to analyze the approximate solution of the Mathieu equation. The theoretical analysis and the numerical simulations show that the approximate solution of the Mathieu equation is close to the dynamic output characteristics of the resonant gyroscope. The experimental analysis shows that the theoretical curve and the experimental data processing results coincide perfectly, which means that the approximate solution of the Mathieu equation can present the dynamic output characteristic of the resonant gyroscope. The theoretical approach and the experimental results of the Mathieu equation approximate solution are obtained, which provides a reference for the robust design of the resonant gyroscope.

Autonomous estimation of angle random walk of fiber optic gyro in attitude determination system of satellite

Angle random walk of fiber optic gyro is a dominant noise source in high-accuracy attitude control system of satellite. The coefficient of angle random walk denotes the magnitude of angle random walk and can be regarded as a “state of health” for gyro diagnosis. However, satellite motion included in gyro output disturbs in-orbit estimation of angle random walk. Moreover, the Allan variance method has too large offline computational effort and data storage requirements to be applied to in-orbit estimation. In addition, with the development of deep space exploration, it is urged that satellite should be more autonomy including autonomous fault diagnosis and reconfiguration. To overcome the barriers and meet satellite autonomy, we present a new autonomous estimation of angle random walk. A difference between angle increments of star sensor and gyro is taken to remove satellite motion from gyro output. Then, a simplified observation model based on Allan variance is proposed to estimate the angle random walk. Simulations show the proposed method correctly estimates the coefficient of angle random walk in real time and tracks the degradation of angle random walk caused by gamma radiation in space. The technique proposed here effectively isolates satellite motion, and requires no data storage and any ground support.

Statistical Modeling of Rate Gyros

Gyroscopes are integral components of inertial measurement units, which are used for guidance and stabilization of many platforms. This paper presents an algorithm for estimating the statistical parameters that govern the performance of rate gyros, i.e., the spectral densities <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> of the angle random walk and rate random walk components, respectively. Previous work on gyro modeling is based on computing the Allan variance of a gyro signal and using a well-known formula for its mean. The algorithm in this paper uses these as well as the following quantities, which are derived in this paper: the theoretical variance of the Allan variance and the covariance between different Allan variance points. The algorithm is developed using the formulation of the best linear unbiased estimator from statistical estimation theory. The performance of the algorithm is demonstrated using simulated and experimental data. A bound on the error in the integral of the gyro output, as a function of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> , is also derived.

Temperature error model in coriolis vibratory gyroscopes

The effect of temperature variations on the output of Coriolis vibratory gyroscope is studied in this paper. Mathematical model of the temperature influences is developed and its parameters are identified using experimental data. The latter has been used to validate obtained mode l

Modeling and compensation of MEMS gyroscope output data based on support vector machine

The modeling and compensation method of the angular rate error of MEMS gyro MG31-300, based on support vector machine, is described in this paper. Reference angular rates were generated by the single-axis rate turntable. The output data of MG31-300 under different input angular rates were collected and analyzed. Considering the nonlinear and random characteristics of the angular rate error, the support vector machine model is established, which uses the output voltage of gyro as the input and provides angular rate error as the output. The resolution of the angular rate error is improved by this modeling method. The result shows that the fitting error of the model was 0.0701°/s (1σ). Finally, within MG31-300 measuring range (−300°/s to 300°/s), some testing points besides the training samples were selected to testify and verify the model. The results indicate that, the support vector machine model has high precision and good generalization ability.

Improved Attitude Algorithm for Fiber-Optic-Gyro Strapdown INS

Rotation vector algorithm regarded as a classical and conventional attitude algorithm is widely used in strapdown inertial navigation system. This kind of algorithm usually uses incremental angle in calculation processes. However, the output of fiber-optic gyro is angular rate. Integrating angular rate to get incremental angle leads calculation errors. In this paper, a set of improved attitude algorithms for fiber-optic-gyro strapdown INS using angular rate are developed and evaluated under classical coning motion. The error criterion for the improved algorithms and conventional ones is derived. Under the standard testing circumstance, i.e. classical coning motion, the accuracy of attitude calculation can be improved at least three orders of magnitude as compared with conventional one. Index Terms—Fiber-optic-gyro, Strapdown, INS

Dynamic angular velocity modeling and error compensation of one-fiber fiber optic gyroscope (OFFOG) in the whole temperature range

Dynamic angular velocity modeling and error compensation of VG095M in the whole temperature range, based on a radial basis function (RBF) neural network, is presented in this paper. With gyro output voltage and environmental temperature as the input and angular velocity as the output, an RBF neural network model is established. The model is trained and validated by the experiment data. The fitting error of the model is 4.3818 × 10−6 deg s−1, which shows that the model has high precision. The experiment data except the data used for modeling were processed with this model. The results show that the maximum, minimum and mean square error of the angular velocity were reduced to 4.6%, 4.3% and 4.7% respectively after compensation.

관성센서를 이용한 스트랩다운 탐색기 훼손영상 복원기법

본 논문에서는 스트랩다운 영상탐색기 개발을 위해 각속도계 정보를 이용한 실용적인 움직임 훼손영상 복원 필터링 기법을 제안한다. 각속도계 편향오차가 움직임 훼손을 기술하기 위한 점확산 함수 파라미터의 불확실성으로 작용한다는 점에 착안하여, 이를 놈 제한조건을 만족하는 파라미터 불확실성으로 가정한 후 움직임 훼손 영상을 불확정 선형 상태 공간 방정식으로 모델링한다. 각속도계 편향오차에 의한 파라미터 불확실성 행렬이 놈 제한 조건을 만족한다는 가정 하에, 순환 선형 강인 칼만필터에 기반한 움직임 훼손영상 복원필터가 설계된다. 실제 IR 영상을 이용하여 제안된 영상훼손 복원 필터가 각속도계 편향 오차가 존재하는 상황에서도 신뢰할만한 영상복원 성능을 제공함을 확인한다. This paper proposes a practical linear recursive robust motion deblurring filter using the inertial sensor measurements for strapdown image seekers. The angular rate information obtained from the gyro mounted on the missile is used to define the PSF(point spread function). Since the gyro output contains a unknown but bounded bias error. the motion blur image model can be expressed as the linear uncertain system. In consequence, the motion deblurring problem can be cast into the robust Kalman filtering which provides reliable state estimates even in the presence of the parametric uncertainty due to the gyro bias. Through the computer simulations using the actual IR scenes, it is verified that the proposed algorithm guarantees the robust motion deblurring performance.

2A1-H07 垂直姿勢で自動ホバリング・物体投下する飛行機型ロボットの開発(飛行ロボット・メカトロニクス(1))

This paper describes our development of small indoor Unmanned Aerial Vehicle (UAV) for the 7^<th> Student Indoor Flying Robot Contest. We designed a conventional airplane type UAV which is capable of dropping object to a designated point by hovering vertically. For this purpose, an attitude-control algorithm and a control system were developed. In order to estimate attitude quaternion from on-board accelerometer and gyroscope output, Extended Kalman Filter is used as the attitude-control algorithm. Then, in order to keep hovering using its control surface, the control system was designed and implemented with a microcontroller. The flight test revealed that the UAV is capable of vertical hovering in order to perform the missions required in the contest.

MEMS Gyro Aided Calibration of Electronic Compass

In this paper, an MEMS gyro aided on line calibration algorithm for electronic compass is presented. This electronic compass module consists of a three-axis AMR sensor, a two-axis MEMS tilt sensor and a one-axis MEMS gyro. The automatic calibration method requires to rotate the electronic compass two full 360-degree revolution. In this rotation procedure, magnetic field data, attitude data and angular rate data are recorded. Based on recorded magnetic field data and attitude data, raw heading data is calculated. This raw heading data is verified by angular rate output of MEMS gyro. Results of experiment show that the accuracy of calibrated compass is better than 0.5 deg and MEMS gyro aided on line calibration algorithm is effective for electronic compass.

PARAMETRIC AMPLIFICATION OF A MEMS GYROSCOPE BY CAPACITANCE MODULATION

Parametric amplification of the output of a MEMS gyroscope is achieved by modulating the sense capacitance, or an auxiliary capacitance having an applied DC voltage. The capacitance modulation is produced by the driven motion of the gyroscope mechanism, so the pump signal of the parametric amplifier is not subject to phase errors in the electronics. The capacitance modulation affects the mechanical gain of the sensor (transfer function from input force to sensor mechanism displacement), as well as the electrical gain of the sensor (transfer function from sensor mechanism displacement to output electrical signal). The mechanical and electrical gains of the sensor become phase-dependent, so the Coriolis rate signal can be amplified while the unwanted quadrature-phase signal is attenuated.

Dual‐EKF‐Based Real‐Time Celestial Navigation for Lunar Rover

A key requirement of lunar rover autonomous navigation is to acquire state information accurately in real‐time during its motion and set up a gradual parameter‐based nonlinear kinematics model for the rover. In this paper, we propose a dual‐extended‐Kalman‐filter‐ (dual‐EKF‐) based real‐time celestial navigation (RCN) method. The proposed method considers the rover position and velocity on the lunar surface as the system parameters and establishes a constant velocity (CV) model. In addition, the attitude quaternion is considered as the system state, and the quaternion differential equation is established as the state equation, which incorporates the output of angular rate gyroscope. Therefore, the measurement equation can be established with sun direction vector from the sun sensor and speed observation from the speedometer. The gyro continuous output ensures the algorithm real‐time operation. Finally, we use the dual‐EKF method to solve the system equations. Simulation results show that the proposed method can acquire the rover position and heading information in real time and greatly improve the navigation accuracy. Our method overcomes the disadvantage of the cumulative error in inertial navigation.

Multistage-Fusion Algorithm for Estimation of Aerodynamic Angles in Mini Aerial Vehicle

Nature is the best teacher of many scientific research and development. One such nature inspired invention is the flight vehicle system. Among these, Mini Aerial Vehicles (MAVs) are a class of flight vehicles which have size close to birds. The current work is inspired by the fact that MAV with Low Aspect Ratio (LAR) wings (Aspect Ratio < 2) has nonlinear lift curves and it does not stall sharply as compared to high aspect ratio wings. This can be utilized in flying the MAVs at lower speeds and at higher angle of attacks. In LAR wings, the lift is constant or keeps increasing up to large Angle of Attack (AOA) which can help in flying the MAV at slow speed. Main focus of the present work is to estimate the AOA, which can be further used for development of control laws. This paper presents a data fusion algorithm for estimating the aerodynamic angles in a MAV. For simulation, true states of the aircraft motion are generated using a flight simulation program and a zero mean white noise is added to few of these states as required for the measurements. These noisy states are used as sensor measurements for estimating the AOA and Side Slip Angle (SSA). The proposed scheme is a multi-stage in which initially Euler angles are estimated and later stages are used for AOA and SSA estimation. In the first stage, the Euler angles are estimated using the accelerometer outputs and the rate gyro outputs and V in an Extended Kalman Filter (EKF) algorithm. As a first attempt for estimation of AOA and SSA, only acceleration, angular rates and airspeed were used as measurement in six states EKF. It was observed that there is a bias of more than 10° ° ° ° present in the estimated aerodynamic angles. Since, it is not possible to have any additional sensors on-board due to weight restriction, a new modification is proposed in which a pseudo estimation of AOA and SSA was used as measurement. This effectively reduces the estimation bias and the mean error in both AOA and SSA, and are below 1°. Nomenclature Fx = Total force along the body x-axis Fy = Total force along the body y-axis Fz = Total force along the body z-axis L = Total moment along the body x-axis M = Total moment along the body y-axis N = Total moment along the body z-axis p = Roll rate q = Pitch rate r = Yaw rate Cx = Force coefficient in the x direction Cy = Force coefficient in the y direction Cz = Force coefficient in the z direction Cl = Moment coefficient in the x direction Cm = Moment coefficient in the y direction

UKF Filtering of UAV MEMS Gyro Based on Time-Series Model

The algorithms and the applications of UKF filtering of UAV MEMS Gyro based on time-series model are presented in this paper. First Gyro output signals are preprocessed and modeled by time-series analysis theory, and then use UKF filtering method to compensating error based on the time-series model. Examples with actual experiment demonstrate that the method has apparent superiority. The simulation result shows that, both in static and dynamic cases, after eliminate the precision error MEMS gyro accuracy can achieve the miniature UAV standards.

Research on Testing Method of Dynamic Characteristic for MEMS-Gyroscope

Gave a test method of the dynamic characteristics about gyroscope. In the process of using Gyroscope, it will be affected by various external factors irresistibly in making the gyroscope working at certain vibration frequency. Designed the experiments of steel plate vibrating to examine the relationship between the sensitive angular rate of gyroscope and vibration frequency. Firstly, fixed the plate on the desk; then made the plate to vibrate, collected the data from the gyroscope which vibrating with steel plate. To analyze the data of collection, gained the dynamic characteristics of gyroscope. In addition, designed rotating floor calibration experiment, calibrated the relationship between input and output of gyroscope and verified the rationality of the steel plate vibrating experiment. The result prove that gain the dynamic characteristics of gyroscope by steel plate vibrating, not only the method is simple but the result also can achieve the good precision.

Autonomous estimation of Allan variance coefficients of onboard fiber optic gyro

Satellite motion included in gyro output disturbs the estimation of Allan variance coefficients of fiber optic gyro on board. Moreover, as a standard method for noise analysis of fiber optic gyro, Allan variance has too large offline computational effort and data storages to be applied to online estimation. In addition, with the development of deep space exploration, it is urged that satellite requires more autonomy including autonomous fault diagnosis and reconfiguration. To overcome the barriers and meet satellite autonomy, we present a new autonomous method for estimation of Allan variance coefficients including rate ramp, rate random walk, bias instability, angular random walk and quantization noise coefficients. In the method, we calculate differences between angle increments of star sensor and gyro to remove satellite motion from gyro output, and propose a state-space model using nonlinear adaptive filter technique for quantities previously measured from offline data techniques such as the Allan variance method. Simulations show the method correctly estimates Allan variance coefficients, R = 2.7965exp−4 °/h2, K = 1.1714exp−3 °/h1.5, B = 1.3185exp−3 °/h, N = 5.982exp−4 °/h0.5 and Q = 5.197exp−7 ° in real time, and tracks degradation of gyro performance from initail values, R = 0.651 °/h2, K = 0.801 °/h1.5, B = 0.385 °/h, N = 0.0874 °/h0.5 and Q = 8.085exp−5 °, to final estimations, R = 9.548 °/h2, K = 9.524 °/h1.5, B = 2.234 °/h, N = 0.5594 °/h0.5 and Q = 5.113exp−4 °, due to gamma radiation in space. The technique proposed here effectively isolates satellite motion, and requires no data storage and any supports from the ground.

Signal Decomposition for Three-Axis Gyroscope

Study Algorithm of roll, pitch and yaw angular velocity for three-axis gyroscope. the gyro have only one sensitive quality, can sensitize the three axial angular velocity of the rotating carrier at the same time. in the case of gyro’s spin angular velocity presence and pitch or yaw angular velocity worked, gyro output signal contain spin, pitch and yaw angular velocity. Through Uniaxial Gravity Accelerometer’s application, the roll, pitch and yaw angular velocity for three-axis gyroscope can be demodulated.