title: An Accurate Calibration Method Based on Velocity in a Rotational Inertial Navigation System.
abstract: Rotation modulation is an effective method to enhance the accuracy of an inertial navigation system (INS) by modulating the gyroscope drifts and accelerometer bias errors into periodically varying components. The typical RINS drives the inertial measurement unit (IMU) rotation along the vertical axis and the horizontal sensors' errors are modulated, however, the azimuth angle error is closely related to vertical gyro drift, and the vertical gyro drift also should be modulated effectively. In this paper, a new rotation strategy in a dual-axis rotational INS (RINS) is proposed and the drifts of three gyros could be modulated, respectively. Experimental results from a real dual-axis RINS demonstrate that the maximum azimuth angle error is decreased from 0.04° to less than 0.01° during 1 h. Most importantly, the changing of rotation strategy leads to some additional errors in the velocity which is unacceptable in a high-precision INS. Then the paper studies the basic reason underlying horizontal velocity errors in detail and a relevant new calibration method is designed. Experimental results show that after calibration and compensation, the fluctuation and stages in the velocity curve disappear and velocity precision is improved.
authors.affiliation: School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing 100191, China. victoryqian175@163.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing 100191, China. 17wanglei@buaa.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing 100191, China. lzj0601@buaa.edu.cn.
authors.forename: Zengjun
authors.initials: Z
authors.lastname: Liu
authors.affiliation: School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing 100191, China. pdfeng@126.com.
authors.forename: Peide
authors.initials: P
authors.lastname: Feng
keywords: azimuth angle error; rotation modulation; rotation strategy; rotational inertial navigation system (RINS); velocity errors