High-Precision Aeromagnetic Compensation Method Under the Influence of the Geomagnetic Field

Aeromagnetic surveys play an important role in geophysical exploration and many other fields. In many applications, magnetometers are installed aboard an aircraft to survey large areas. Due to its composition, an aircraft has its own magnetic field, which degrades the reliability of the measurements, and thus a technique (named aeromagnetic compensation) that reduces the effect of magnetic interference is required. Commonly, based on a figure-of-merit (FOM) flight, this issue is solved as a linear regression problem. However, the influence of the geomagnetic field, which refers to the magnetic interference introduced by the non-uniform magnetic field in the region, creates accuracy problems when estimating the model coefficients. The analysis in this study indicates that the geomagnetic field can be obtained by a data processing method based on Gaussian-process-regression (GPR) combined with the measurement process. Accordingly, we propose a high-precision compensation method, designated as the Geomagnetic Field-Based (GF-Based) method, which isolates geomagnetic influence to enhance calibration fidelity. This method restricts the impact of the geomagnetic field and improves the precision of the calibration. Compared with the existing methods which considered the geomagnetic field, the proposed method improves the improved ratio (IR), which is verified by a set of airborne experiments.