What are the two Exclusion Zone Angles?
Note that two exclusion zones are defined in Recommendation ITU-R S.1503-2, namely:
| Parameter | Description |
|---|---|
| MIN_EXCLUDE | Exclusion zone angle (degrees), the minimum angle to the GSO arc at the non-GSO ES at which it will operate, defined either at the ES ( angle) or at the satellite (X angle) |
| ES_MIN_GSO | Minimum angle to GSO arc (degrees) at which the ES will transmit defined at the ES ( angle) |
These should be consistent which suggests it is better to use the α angle. MIN_EXCLUDE is specified in the EPFD(down) algorithm while ES_MIN_GSO for the EPFD(up) calculation, but they should be the same.
Note these are derived from the two Appendix 4 parameters:
A.4.b.7.d.2 if the zone is based on a topocentric angle or a satellite-based angle, the width of the zone, in degrees
A.14.b.5 the minimum separation angle between the geostationary-satellite orbit arc and the associated earth station main beam-axis at which the associated earth station can transmit towards a non-geostationary satellite