Single-axis rotation/azimuth-motion insulation inertial navigation control system with FOGs

Abstract

Rotation modulation technology could effectively improve the accuracy of the inertial navigation system (INS) by compensating for the biases of the inertial sensors automatically. However, the carrier angular motion and rotation control error could reduce the rotation modulation effect and then decrease the navigation accuracy. To address this problem, for the single-axis rotation INS, a novel rotation control scheme is presented. The control scheme employs the fiber optic gyros to control the inertial measurement unit (IMU) rotation angular velocity so that the INS with both rotation modulation and azimuth motion insulation functions. Furthermore, in order to reduce the control error, this study adopts two ways: optimizing the control strategy and shortening the delay time. The former way is to control the IMU rotating about the z-axis of the platform frame with respect to the navigation frame, rather than the up-axis of the navigation frame. The latter way is to apply interrupt mode rather than inquiry mode to complete the data transfer between the navigation and the control processors. The simulation and experimental results demonstrate that: the proposed method would not only realize the rotation modulation of the biases of the inertial sensors, but also achieve the insulation of the azimuth motion. The steady-state control error of the control system is less than 10" and the overshoot control error is less than 50". Compared to the traditional SRINS, the navigation position error in the single-axis rotation/azimuth-motion insulation INS could reduce 50% in some navigation application.

Adaptive Kalman filter based on multiple fading factors for fast in-motion initial alignment with rotation modulation technique

“…4 Among the above categories, the single-axis rotational inertial navigation system (SRINS) is most commonly used for its simple structure, simple design and small volume, with the z-axis usually taken as the rotation axis. [5][6][7] However, SRINS can modulate only the constant errors perpendicular to the rotation axis, and the constant errors along the rotation axis still exist. In light of this, there is a necessity to further explore how to compensate for the constant errors along the rotation axis for the highaccuracy navigation applications of MEMS.…”

A Low-Cost MEMS Missile-Borne Compound Rotation Modulation Scheme

“…Different rotation schemes are designed to minimize systematic errors. Various rotation modulation schemes designed for fiber optic gyroscope (FOG) have strong reference significance for MEMS inertial navigation [ 16 , 17 ]. However, compared with the fiber optic gyroscope, the MEMS sensor has a larger constant error and larger noise, and the error component is more complex [ 18 ].…”

Analysis and Self-Calibration Method for Asynchrony between Sensors in Rotation INS

“…The widely used and researched RINS can be divided into several categories according to different classifications. In terms of the rotation mode, the RINS can be divided into continuous rotation RINS and discontinuous rotation RINS [ 9 , 10 , 11 , 12 , 13 ]. The constant errors of the sensors are modulated into sine or cosine form by the continuous rotation scheme [ 9 , 10 ].…”

“…An 8-position discontinuous rotation scheme is proposed in [ 12 , 13 ]. With respect to the rotation axis, the RINS can be divided into single-axis RINS, dual-axis RINS and triple-axis RINS [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. The differences between single-axis RINS and dual-axis RINS are studied in [ 15 ].…”