Geomagnetic field modeling from on-board LEO attitude-control magnetometer

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The proposed research aims to separate and model the core components in the geomagnetic field from the magnetometer measurements that have been used in attitude control of satellites, in order to fill temporal coverage gaps that exist between conventional satellite magnetic missions and to improve our understanding of the Earth's magnetic properties and its origin. The satellite magnetic data will provide key insights on the geomagnetic field model (GFM), which is based largely on ground observatory data that has poor and biased coverage. The GFM also relies on the conventional satellite magnetic data, but significant temporal gaps exist between missions. Fortunately, low-Earth orbit satellites carry on-board attitude control magnetometers (TAMs). It was recently determined that only 3 days of TAM measurements from the KOMPSAT-1 satellite were found to provide important knowledge on the behaviour of the magnetic field for the roughly 30 years since 1958, when conventional magnetic missions were unavailable. Accordingly, a study is proposed to investigate the use of comprehensive TAM data from the entire measurement data of KOMPSAT-1 and -2 satellites and conventional magnetic data from other magnetic survey satellites. Procedures and state-of-the-art data processing techniques will include coordinate transformation, spectral correlation filtering, quadrant-swapping, spherical harmonic coefficient calculation, and subsurface modeling. As research outcomes, the total field map and the spherical harmonic core field model can be used to update global models. The results of the subsurface modeling will also improve our understanding of crustal distribution of hydrocarbons and mineral resources, as well as geological hazards.