Abstract
An inertial navigation system (INS) has been widely used in challenging GPS environments. With the rapid development of modern physics, an atomic gyroscope will come into use in the near future with a predicted accuracy of 5 × 10−6°/h or better. However, existing calibration methods and devices can not satisfy the accuracy requirements of future ultra-high accuracy inertial sensors. In this paper, an improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors and lever arm errors. A systematic calibration method is proposed based on a 51-state Kalman filter and smoother. Simulation results show that the proposed calibration method can realize the estimation of all the parameters using a common dual-axis turntable. Laboratory and sailing tests prove that the position accuracy in a five-day inertial navigation can be improved about 8% by the proposed calibration method. The accuracy can be improved at least 20% when the position accuracy of the atomic gyro INS can reach a level of 0.1 nautical miles/5 d. Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs) using common turntables, has a great application potential in future atomic gyro INSs.
Highlights
An inertial navigation system (INS) is widely used in military and civilian application domains because it is entirely self-contained and can provide high-rate position, velocity and attitude information
Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs) using common turntables, has a great application potential in future atomic gyro INSs
With the rapid development of modern physics, atomic gyroscopes have been demonstrated in recent years [1]
Summary
An inertial navigation system (INS) is widely used in military and civilian application domains because it is entirely self-contained and can provide high-rate position, velocity and attitude information. For improving the calibration accuracy of an optic gyro IMU, Cai et al [7] and Pan et al [8] proposed different calibration methods while considering the accelerometer second order nonlinear scale factor. It cannot satisfy the requirement of ultra-high accuracy atomic gyro IMUs. For example, the effect of gravity on atoms in an atom interferometer is much bigger than that on photons in an optic interferometer, the g-sensitivity errors, which is discussed by Chen et al [9] and Zheng et al [10], cannot be ignored in an atomic gyro IMU. An improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors, and lever arm errors Another restriction factor is the accuracy of the calibration equipment and methods.
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