High-Precision Electrical Determination and Correction of Attitude Deviation for the Coil Vector Magnetometer

Abstract

Coil vector magnetometer is an advanced instrument that can perform integrated multi-element geomagnetic measurements and has excellent prospects for geoscience research and resource exploration applications. The attitude deviation is one of the main error sources of magnetic direction measurements of the coil vector magnetometer. The existing attitude determination method requires the use of additional auxiliary instruments (e.g., a spirit level). Furthermore, this method cannot be used to perform direct determination of the directional shift of the bias field caused by attitude deviation, and the magnetism of the detection instrument inevitably introduces new measurement errors. Therefore, it is difficult to achieve high-precision attitude deviation correction. To address this issue, we propose a novel electrical method to enable direct, high-precision determination of the attitude deviation and the corresponding correction indicator for the coil vector magnetometer by using only a single rotation of the magnetometer and applying bias fields, thereby realizing comprehensive high-precision hard and soft corrections of the attitude deviation via indicator alignment without relying on auxiliary detection instruments. In addition, we developed a dedicated experimental platform and then validated both the practicality and the performance of the proposed method in a geomagnetic observatory. Comparative experimental results for two coil vector magnetometers indicate that when the correction indicator’s alignment inaccuracy is less than 1 nT, the magnetic direction measurement error caused by the attitude deviation can be less than 6′′.