Enhanced Aeromagnetic Compensation Models for Magnetic Anomaly Target Detection

This article is concerned with the aeromagnetic compensation, which extracts and subtracts the disturbing magnetic fields generated by the aircraft itself. It is a crucial step in aeromagnetic anomaly target detection. The classical Tolles-Lawson (TL) model is established based on many assumptions, including at least the following three points. First, the nonorthogonality, zero offsets, and nonlinearity of the triaxial fluxgate are ignorable. Second, the aircraft has no movable part and keeps rigidity during flying. Third, the ambient electric field does not induce current on the aircraft surface to produce extra magnetic interference. By taking account of these factors, enhanced models are derived in this work. Meanwhile, fitting and filtering schemes are introduced to suppress the impacts of geomagnetic gradient and diurnal magnetic variations. Field experimental data are used to examine the enhanced models and algorithms. Compared with the original TL model, the proposed models can significantly improve the compensation accuracy and signal-to-noise ratio, which facilitates the subsequent detection for a magnetic anomaly target.