Platform–corrected analyses of near-bottom magnetic data acquired by autonomous underwater vehicles

Abstract

Autonomous underwater vehicles (AUVs) provide high-resolution magnetic measurements essential for investigating crustal accretion, tectonic segmentation, and hydrothermal processes at mid-ocean ridges. However, raw magnetometer measurements are strongly influenced by platform-induced magnetic fields, attitude-dependent biases, and navigation uncertainties that must be corrected to recover geophysically meaningful anomaly fields. We apply a procedure to measurements from AUVs which includes platform independent scalar calibration, transformation into geographic reference frames, spin-based removal of permanent and induced vehicle magnetization, and computation of magnetic anomalies relative to the International Geomagnetic Reference Field. The framework also incorporates a two-dimensional spectral upward continuation to reconcile altitude variations, thereby recovering anomalies at a uniform reference level. Application of this system to AUV datasets from the East Pacific Rise and Mid-Atlantic Ridge demonstrates effective suppression of platform biases, improved crossover consistency, and the generation of internally coherent geomagnetic anomaly fields suitable for subsequent analysis and mapping.