Geometrical control of scintillation indices: what happens for GPS satellites

Geometrical control of the effective outer scale imposed by detrend filtering, in the
presence of highly anisotropic irregularities, explains differences between scintillation
indices ratio at different locations. On the basis of weak scatter theory results, the behavior
of the geometrical factor G, responsible for static effect of diffraction, is investigated in the
case of GPS satellites. A simple comparison is made between GPS satellites and polar
orbiting satellites used in the past for scintillation experiments to understand such
differences in the behavior of scintillation indices measured by means of GPS scintillation
monitors.