Novel Calibration Algorithm for a Three-Axis Strapdown Magnetometer

Yan Liu

doi:10.3390/s140508485

2014-05-14

DOI：10.3390/s140508485

原文链接

查看原文

摘要

En 中文

A complete error calibration model with 12 independent parameters is established by analyzing the three-axis magnetometer error mechanism. The said model conforms to an ellipsoid restriction, the parameters of the ellipsoid equation are estimated, and the ellipsoid coefficient matrix is derived. However, the calibration matrix cannot be determined completely, as there are fewer ellipsoid parameters than calibration model parameters. Mathematically, the calibration matrix derived from the ellipsoid coefficient matrix by a different matrix decomposition method is not unique, and there exists an unknown rotation matrix R between them. This paper puts forward a constant intersection angle method (angles between the geomagnetic field and gravitational field are fixed) to estimate R. The Tikhonov method is adopted to solve the problem that rounding errors or other errors may seriously affect the calculation results of R when the condition number of the matrix is very large. The geomagnetic field vector and heading error are further corrected by R. The constant intersection angle method is convenient and practical, as it is free from any additional calibration procedure or coordinate transformation. In addition, the simulation experiment indicates that the heading error declines from +/- 1 degrees calibrated by classical ellipsoid fitting to +/- 0.2 degrees calibrated by a constant intersection angle method, and the signal-to-noise ratio is 50 dB. The actual experiment exhibits that the heading error is further corrected from +/- 0.8 degrees calibrated by the classical ellipsoid fitting to +/- 0.3 degrees calibrated by a constant intersection angle method.

Keyword:

constant intersection angle assumption

ellipsoid fitting

restricted least squares solution

rotation matrix