一种简单的低成本航姿系统标定及修正方法

A Straightforward Calibration and Correction Technique for Inexpensive Attitude and Heading Reference Systems

摘要:

在对低成本航姿系统进行加速度计与磁力计的标定中，通常磁力计的信噪比更低，仅使用椭球拟合法标定传感器误差参数结果是不够精确的。为了提高标定结果的准确性，提出了一种在多位置条件下基于椭球拟合约束和点积法的误差参数标定及修正方法。首先，在静态多位置下获取15对低噪声的测量数据并进行椭球拟合标定，其次，用补偿后的磁力计数据分布特征构建椭球约束条件，通过点积法计算地磁矢量与水平面夹角，并以其均方差来量化修正效果，对磁力计中可观性差的轴间不正交误差参数和传感器间非对准误差参数进行修正，最终提升标定效果。仿真和实测的试验结果表明，在同等椭球拟合约束下，本方法相比于独立使用椭球拟合法和点积不变法，地磁矢量与水平面夹角的均方差下降了25%以上，且具有简单易用的特点。

Abstract:

In the calibration of accelerometers and magnetometers for inexpensive attitude and heading reference systems, often the signal-to-noise ratio of magnetometers is much lower and the results of calibrating the sensor error parameters using only ellipsoidal fitting are not accurate enough. In order to improve the accuracy of the calibration results, an error parameter calibration and correction method under multi-position conditions is proposed, based on ellipsoid fitting constraints and dot product method. First, 15 pairs of low-noise measurements were acquired at static multiple positions and calibrated with ellipsoid fitting, and secondly, constructing ellipsoidal constraints using the data distribution characteristics of the compensated magnetometer, the angle between the geomagnetic vector and the horizontal plane is calculated by the dot product method, and the correction effect is quantified in terms of its mean square error. Correct the parameter of the magnetometer's inter-axis non-orthogonal error, which is less observable, and the inter-sensor non-alignment error. Ultimately improve the calibration results. Simulated and measured experimental results show that under the same ellipsoid fitting constraints, this method reduces the mean square error of the angle between the geomagnetic vector and the horizontal plane by more than 25% compared to the independent use of ellipsoid fitting and dot product invariant methods, and it is simple and easy to use.