基于航向匹配的磁力计外场无依托标定算法CSCD

三轴磁力计的测量精度会受到自身和环境的影响,因此在使用前必须要进行标定。传统标定方法需要特定的精密仪器和标定环境,或是对计算量和采集数据的方式有较高的要求,针对这些问题,提出了基于航向匹配的磁力计外场无依托标定算法。该算法无需特定精密仪器、对数据采集和计算量的要求也较低,且可以在现场实现有效动态标定。该算法基于航向角是磁航向角与磁偏角代数和的原理,通过等价数学变换构建了磁力计零偏关于姿态角与磁力计测量值的线性模型,最终采用最小二乘法对磁力计的零偏进行估计。该算法可以估计三轴磁力计的零偏,对磁力计的测量结果有较好的补偿作用。实验结果表明,该算法可有效标定三轴磁力计,减小其测量误差。经标定的磁力计可以应用于地磁匹配导航,辅助惯性导航修正其位置误差,尤其是在长直路段内,磁力计标定过程中识别出的磁异常数据可以为地磁匹配导航提供基础信息。

Outdoor Calibration Algorithm Without Instrumental Assistance of Triaxial Magnetometer Based on Heading Matching

The measurement accuracy of the triaxial magnetometer will be affected by itself and the environment, which means it must be calibrated before using. The outdoor calibration algorithm without instrumental assistance of triaxial magnetometer which is based on heading matching was proposed for the reason that traditional calibration methods need specific precision instruments and calibration environment, or have high requirements for the amount of computation and the way of collecting data. The algorithm does not need specific precision instruments, has low requirements for data acquisition and calculation, and can realize effective dynamic calibration on site. The algorithm is based on the principle that the heading angle is the algebraic sum of the magnetic heading angle and the magnetic declination angle. The linear model of the zero bias of the magnetometer with respect to the attitude angle and the measured value of the magnetometer is constructed through equivalent mathematical transformation. Finally, the least square method is used to estimate the magnetometer''s zero offset. This algorithm can estimate the zero offset of the triaxial magnetometer and has a good compensation effect on the measurements of the magnetometer. The experimental results show that the algorithm can effectively calibrate the triaxial magnetometer and reduce the measurement error of the magnetometer. The calibrated magnetometer can be applied to geomagnetic matching navigation to assist inertial navigation and correct its position error. Especially in the long straight section of the road, the geomagnetic anomaly data identified during the magnetometer calibration process can provide basic information for geomagnetic matching navigation.