Scope

Recommendation ITU-R P.531 describes a method for evaluating the ionospheric propagation effects on paths between Earth and space (at frequencies from 0.1 to 12 GHz) "OR" (at frequencies above the ionosphere critical frequency, where the ionosphere becomes transparent to radio-waves, to several tens of gigahertz). The following effects may take place on paths between Earth and space when the signal is passing through the ionosphere:

- rotation of the polarization (Faraday rotation) due to the interaction of the electromagnetic wave with the ionized medium in the Earth's magnetic field along the path;

- group delay and phase advance of the signal due to the total electron content (TEC) accumulated along the path;

- rapid variation of amplitude and phase (scintillations) of the signal due to small-scale irregular structures in the ionosphere;

- a change in the apparent direction of arrival due to refraction;

- Doppler effects due to non-linear polarization rotations and time delays.

The data and methods described in this Recommendation are applicable for planning satellite systems, in respective ranges of validity indicated in the Annex.