JOURNAL OF GEOPHYSICAL RESEARCH, VOL.???, XXXX, DOI:10.1029/, Geomagnetic main field modeling with DMSP1

launches12 and maintains a network of satellites to monitor the meteorological, oceano-13 graphic, and solar-terrestrial physics environments. In the past decade, ge-14 omagnetic field modelers have focused much attention on magnetic measure-15 ments from missions such as CHAMP, Ørsted and SAC-C. With the com-16 pletion of the CHAMP mission in 2010, there have been no satellite-based17 vector magnetic field measurements available for main field modeling. In this18 study, we calibrate the Special Sensor Magnetometer (SSM) instrument on-19 board DMSP to create a dataset suitable for main field modeling. These vec-20 tor field measurements are calibrated to compute instrument timing shifts,21 scale factors, offsets, and non-orthogonality angles of the fluxgate magne-22 tometer cores. Euler angles are then computed to determine the orientation23 of the vector magnetometer with respect to a local coordinate system. We24 fit a degree 15 main field model to the dataset and compare with the World25 Magnetic Model (WMM) and Ørsted scalar measurements. We call this model26 DMSP-MAG-1 and its coefficients and software are available for download27 a