Manuscript received August 03, 2010; accepted November 14, 2010. Date
of publication December 30, 2010; date of current version May 27, 2011.
This work was supported by the German Federal Ministry of Economics and
Technology via the German Space Agency (DLR), Grant 50 OK 0801, for the
GREAT receiver commissioning work and as subcontractor to the University
of Arizona for STO, NASA suborbital Grant NNX08AG39G.