Can there be Longitude Variation in the PFD mask?

It is likely that the PFD generated by a satellite will vary as it moves geographically. For example, there is likely to be higher PFD values when the satellite is over traffic hot-spots and lower when over low traffic areas such as the major oceans.

Note, however, that there is no identification any part of the algorithm in S.1503-2 or the PFD mask as to actual geographic regions, whether specified by longitudes, country borders or ITU-R Regions.

The PFD mask should be calculated and provided for the traffic hot-spot as this is the case that determines whether the EPFD thresholds are met or not. As noted in the section above on modelling spot beam systems, the analysis is undertaken for the highest traffic location taking into account re-use constraints within the non-GSO system.

The PFD mask can vary by latitude, and the mask should give the highest PFD for each angle (such as azimuth and elevation) for that latitude over all longitudes over the constellation’s lifetime.