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Schlagwörter:
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Zusammenfassung:
UAVs represent a tremendous opportunity to perform geophysical and repeated experiments, particularly in volcanic contexts. Their ability to be deployed rapidly, to fly at various altitudes, the fact that they are easy to operate, make them attractive for magnetic surveys. Detailed maps of the magnetic field bring in turn key constraints on the composition, thermal anomalies, intrusive systems, and crustal contrast evolutions. Yet, raw magnetic field measurements require careful processing to minimize directional, positional, and crossover errors. Moreover, stitching together adjacent or overlapping surveys acquired at different times and altitudes is not a trivial task. Therefore, it is challenging in remote areas to evaluate directly the consistency of a survey and to ascertain its success.
In this paper, we first present a very fast algorithm (<1s) allowing an automatic visualization of data inconsistencies with applied corrections. The field measurements are corrected for the International Geomagnetic Reference Field, projected along the ambient main field, and modelled by iteratively reweighted least-squares in terms of rectangular harmonic functions. The software therefore exploit the quality indices provided with data and mitigates the effect of outliers. The final maps for the scalar anomaly field as well as for the vector components are readily available and obey potential field theory. Two cases studies are presented, one for the Piton de la Fournaise volcano (La Réunion, France) and the second for the Petit Puy de Dôme (Massif Central, France).
