ITU-R S.1713-1 PDF

This Recommendation provides methodologies to calculate the minimum separation angle anywhere on the Earth's surface between a high Earth orbit (HEO) satellite in its "active" arc and:

a) all visible locations in the GSO arc;

b) a specific GSO satellite.

The first methodology (see Annex 3) is useful for determining if a HEO system complies with the equivalent power flux density (epfd) limits in frequency bands where Radio Regulations Article 22 epfd limits apply. The second (see Annex 5) is useful for interference assessment between a specific GSO network and a HEOtype FSS satellite.