The surge in new satellite communications services is placing a huge
pressure on the frequency spectrum. Many services now have to share the
same frequencies, which can cause interference problems. In particular,
new non-Geostationary Orbit (NGSO) systems will have to share certain
frequencies with established GSO systems. Planners must work out how much
interference the GSO systems can tolerate and then how much power the
new systems can safely be allowed to radiate. They must also establish
geographical boundaries around the Earth stations that receive satellite
signals, where these limits should apply.
The aim of this project is to contribute to the international regulations
that govern these issues. RCRU researchers are working on models that
predict how much interference GSO systems can tolerate, taking into account
the fact that rainfall fades their signals and makes them more vulnerable
to unwanted signals. The unit has also investigated how many existing
links may be at risk under the current limits on interfering non-GSO systems.
They are assessing how suitable existing radiowave propagation models
are for working out the co-ordination areas around Earth receiving stations,
especially for future systems that will use even higher frequencies.
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