Generic definitions

Space radiocommunication: Any radiocommunication involving the use of one or more space stations or the use of one or more reflecting satellites or other objects in space.

Radiodetermination: The determination of the position, velocity and/or other characteristics of an object, or the obtaining of information relating to these parameters, by means of the propagation properties of radio waves.

Radionavigation: Radiodetermination used for the purposes of navigation, including obstruction warning.

Radio astronomy: Astronomy based on the reception of radio waves of cosmic origin.

Radiolocation: Radiodetermination used for purposes other than those of radionavigation.

Radio station (or station): One or more transmitters or receivers or a combination of transmitters and receivers, including the accessory equipment, necessary at one location for carrying on a radiocommunication service, or the radio astronomy service.

Earth station (terrestrial segment): A  station located either on the Earth’s surface or within the major portion of the Earth’s atmosphere and intended for communication:

- with one or more space stations; or
- with one or more stations of the same kind by means of one or more reflecting satellites or other objects in space.

Mobile earth station: An earth station in the mobile-satellite service intended to be used while in motion or during halts at unspecified points.

Space station: A station located on an object which is beyond, is intended to go beyond, or has been beyond the major portion of the Earth's atmosphere.

Space system: Any group of cooperating earth stations and/or space stations employing space radiocommunication for specific purposes.

Satellite system: A space system using one or more artificial earth satellites.

Satellite network: A satellite system or part of a satellite system, consisting of only one satellite and the cooperating earth stations.

Geosynchronous satellite: An earth satellite whose period of revolution is equal to the period of rotation of the Earth about its axis.

Geostationary satellite: A geosynchronous satellite whose circular and direct orbit  lies in the plane of the Earth’s equator and which thus remains fixed relative to the Earth.

Non-geostationary satellite: A satellite that is not geosynchronous and which orbit depends from both inclination and eccentricity.

Satellite link: A radio link between a transmitting earth station and a receiving earth station through one satellite. A satellite link comprises one up-link (Earth to space) and one down-link (space to Earth).

Feeder link: A radio link from an earth station at a given location to a space station, or vice-versa, conveying information for a space radiocommunication service other than for the fixed satellite service. The given location may be at a specified fixed point, or at any fixed point within specified areas

Radiocommunication service: A service involving the transmission, emission and/or reception of radio waves for specific telecommunication purposes.

Fixed-satellite service: A radiocommunication service between earth stations, at given positions, when one or more satellites are used. In some cases, this service includes satellite-to-satellite links, which may also be operated in the  inter-satellite service; the fixed-satellite service may also include feeder links for other space radiocommunication services.

Mobile-satellite service: A radiocommunication service:

- between mobile earth stations and one or more space stations, or between space stations used by this service; or
- between mobile earth stations by means of one or more space stations.

This service may also include feeder links necessary for its operation.

Broadcasting-satellite service: A radiocommunication service in which signals transmitted or retransmitted by space stations are intended for direct reception by the general public.

In the broadcasting-satellite service, the term ''direct reception'' shall encompass both individual reception and community reception.

Earth exploration-satellite service: A radiocommunication service between earth stations and one or more space stations, which may include links between space stations, in which:

- information relating to the characteristics of the Earth and its natural phenomena, including data relating to the state of the environment, is obtained from active sensors or passive sensors on Earth satellites;
- similar information is collected from airborne or Earth-based platforms;
- such information may be distributed to earth stations within the system concerned;
- platform interrogation may be included.

This service may also include feeder links necessary for its operation.

Space operation service: A radiocommunication service concerned exclusively with the operation of spacecraft, in particular space tracking, space telemetry and space telecommand.

These functions will normally be provided within the service in which the space station is operating.

Radiodetermination-satellite service: A radiocommunication service for the purpose of radiodetermination involving the use of one or more space stations.

This service may also include feeder links necessary for its own operation.

Meteorological-satellite service: An earth exploration-satellite service for meteorological purposes.

Radionavigation-satellite service: A radiodetermination-satellite service used for the purpose of radionavigation.

This service may also include feeder links necessary for its operation.

Space research service: A radiocommunication service in which spacecraft or other objects in space are used for scientific or technological research purposes.

Radio astronomy service: A service involving the use of radio astronomy.