Earth Planets Space, Vol. 58 (No. 4), pp. 397-407, 2006
S. Maus1, H.Lühr1, and M. Purucker2
1GeoForschungsZentrum, 14473 Potsdam, Germany
2Raytheon ITSS at Geodynamics Branch, GSFC/NASA Greenbelt, MD 20771, USA
(Received January 15, 2005; Revised June 3, 2005; Accepted June 27, 2005; Online published April 14, 2006)
A primary objective of the Swarm constellation mission is to resolve the lithospheric magnetic field with the best achievable accuracy in order to bridge the spectral gap between satellite and airborne/marine magnetic sur-veys. In a series of end-to-end simulations, the possibilities of high degree field recovery were investigated. The proposed constellation consists of a higher and a lower pair of satellites. It was soon found that a constellation as such does not yet guarantee improved high degree field recovery. Of crucial importance is the orbit constellation of the lower pair of satellites. If the lower satellites follow each other, as investigated in Constellation 1, the gain of a constellation turns out to be marginal, compared to a single satellite. For Constellation 2, the lower satellites were separated in the E/W direction. In this setup, one can use the instantaneous E/W magnetic field gradient between the satellites, as well as the N/S along track gradients. Incorporating this vector gradient information results in significantly improved field resolution. Indeed, the final simulation suggests that the envisaged Swarm constellation will enable the recovery of the lithospheric field to beyond spherical harmonic degree 130.
Key words: Geomagnetic field, magnetic field modeling, crustal magnetic field.