WRC 2027 Agenda Item Details

Studies of technical and regulatory provisions necessary to protect radio astronomy operating in specific Radio Quiet Zones (RQZs) and, in frequency bands allocated to the radio astronomy service on a primary basis globally, from aggregate radio-frequency interference caused by systems in the non-geostationary-satellite orbit. The ITU-R is invited to:

1. study how interference from unwanted emissions from a single non-GSO satellite system operating in the adjacent and nearby frequency bands to those in Table 1 affects the operation of RAS station in bands for which they are primary
2. study how the aggregate interference from unwanted emissions from multiple non-GSO satellite systems in the adjacent and nearby frequency bands in Table 1 affect the operation of RAS stations in bands for which they are primary
3. study possible recognition of RQZs based on their characteristics and existing ITU-R studies
4. study how the aggregate interference from single and multiple non-GSO satellites systems affects the operation of RAS stations in the RQZs
5. study on new coexistence measures between non-GSO satellite systems and RAS station in the RQZs
6. study methods to calculate the necessary separation distances between gateways of non-GSO systems and RAS stations protected by the RQZs

WRC-23 is invited to review the results of these studies and take necessary actions, as appropriate

Examples of the remote RAS stations include the Square Kilometre Array Observatory in South Africa and the Atacama Large Millimetre/submillimetre Array in Chile. Table 1 frequencies are

1. RAS band 10.7 - 10.7 GHz, active service frequency bands 10.7 - 10.95 GHz (FSS)
2. RAS band 42.5 - 43.5 GHz, active service frequency bands 42 - 42.5 GHz (FSS)
3. RAS band 76 - 77.5 GHz, active service frequency bands 74 - 76 GHz (FSS, MSS)
4. RAS band 94.1 - 95 GHz, active service frequency bands 95 - 100 GHz (RNSS, MSS
5. RAS band 100 - 102 GHz, active service frequency bands 95 - 100 GHz (RNSS, MSS)
6. RAS band 114.25 - 116 GHz, active service frequency bands 116 - 119.98 GHz (FSS)
7. RAS band 130 - 134 GHz, active service frequency bands 123 - 130 GHz (FSS, MSS, RNSS)

Visualyse Professional can model the RAS and also the non-GSO satellite systems, both single systems and aggregate covered by this agenda item. It can model both co-frequency and non-co-frequency interference scenarios and non-GSO systems in the FSS, MSS and RNSS services. It can also model those non-GSO systems with fixed pointing beams or steerable spot beams systems, and both space-to-Earth interference paths or terrestrial paths between gateways and RAS stations and use metrics including EPFD. We can model RQZs in a number of ways including frequency and geographic separation and PFD management.

We can undertake studies including analysis of sharing between the different services covered by this agenda item including RAS and non-GSO FSS, MSS and RNSS. We can assist in modelling these scenarios and defining RQZs. We can help identify suitable system characteristics and sharing criteria, and provide contributions and representation at ITU-R Working Parties. Using our in house Visualyse Professional we can quickly model a very wide range of systems, services and scenarios.