to consider studies on the technical and regulatory provisions necessary to protect radio astronomy operating in specific Radio Quiet Zones, and in frequency bands allocated to the radio astronomy service on a primary basis globally, from aggregate radio-frequency interference caused by non-geostationary-satellite orbit systems, in accordance with Resolution 681 (WRC-23)

Regulatory & procedural considerations

The protection framework today

• The radio astronomy service holds primary allocations in specific frequency bands globally, and No. 29.12 highlights its susceptibility to harmful interference from space-borne transmitters.
• A Radio Quiet Zone (RQZ) is a recognised geographic area within which the usual spectrum management procedures are modified to reduce or avoid interference with radio telescopes (Report ITU-R RA.2259).
• Two facilities are named for the RQZ studies: the Square Kilometre Array Observatory in South Africa and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, each afforded a national RQZ.

Sharing conditions today

The Bureau currently performs no examinations under Articles 9 or 11 with regard to protecting radio astronomy from satellite systems. National RQZ regulations differ between administrations and may not be applicable to satellite operations, and some non-GSO systems already operate in frequency bands adjacent to primary radio-astronomy allocations.

Constraints carried into the study

Resolution 681 directs the studies at single-system and aggregate interference from non-GSO unwanted emissions into the primary radio-astronomy bands of its Table 1, at the possible recognition of the two named RQZs, and at coexistence measures and methods to calculate separation distances between non-GSO gateways and the protected stations. Protection measures agreed bilaterally between administrations remain outside its scope.