interference: The effect of unwanted energy due to one or a combination of emissions, radiations, or inductions upon reception in a radiocommunication system, manifested by any performance degradation, misinterpretation, or loss of information which could be extracted in the absence of such unwanted energy.
permissible interference: Observed or predicted interference which complies with quantitative interference and sharing criteria contained in these Regulations or in ITU-R Recommendations or in special agreements as provided for in these Regulations.
accepted interference3: Interference at a higher level than that defined as permissible interference and which has been agreed upon between two or more administrations without prejudice to other administrations.
harmful interference: Interference which endangers the functioning of a radionavigation service or of other safety services or seriously degrades, obstructs, or repeatedly interrupts a radiocommunication service operating in accordance with Radio Regulations (CS).
protection ratio (R.F.): The minimum value of the wanted-to-unwanted signal ratio, usually expressed in decibels, at the receiver input, determined under specified conditions such that a specified reception quality of the wanted signal is achieved at the receiver output.
coordination area: When determining the need for coordination, the area surrounding an earth station sharing the same frequency band with terrestrial stations, or surrounding a transmitting earth station sharing the same bidirectionally allocated frequency band with receiving earth stations, beyond which the level of permissible interference will not be exceeded and coordination is therefore not required.
coordination contour: The line enclosing the coordination area.
coordination distance: When determining the need for coordination, the distance on a given azimuth from an earth station sharing the same frequency band with terrestrial stations, or from a transmitting earth station sharing the same bidirectionally allocated frequency band with receiving earth stations, beyond which the level of permissible interference will not be exceeded and coordination is therefore not required.
equivalent satellite link noise temperature: The noise temperature referred to the output of the receiving antenna of the earth station corresponding to the radio frequency noise power which produces the total observed noise at the output of the satellite link excluding noise due to interference coming from satellite links using other satellites and from terrestrial systems.
effective boresight area (of a steerable satellite beam): An area on the surface of the Earth within which the boresight of a steerable satellite beam is intended to be pointed.
There may be more than one unconnected effective boresight area to which a single steerable satellite beam is intended to be pointed.
effective antenna gain contour (of a steerable satellite beam): An envelope of antenna gain contours resulting from moving the boresight of a steerable satellite beam along the limits of the effective boresight area.
1.9. Technical terms relating to space
deep space: Space at distances from the Earth equal to, or greater than, 2 × 106 km.
spacecraft: A man-made vehicle which is intended to go beyond the major portion of the Earth's atmosphere.
satellite: A body which revolves around another body of preponderant mass and which has a motion primarily and permanently determined by the force of attraction of that other body.
active satellite: A satellite carrying a station intended to transmit or retransmit radiocommunication signals.
reflecting satellite: A satellite intended to reflect radiocommunication signals.
active sensor: A measuring instrument in the earth exploration-satellite service or in the space research service by means of which information is obtained by transmission and reception of radio waves.
passive sensor: A measuring instrument in the earth exploration-satellite service or in the space research service by means of which information is obtained by reception of radio waves of natural origin.
orbit: The path, relative to a specified frame of reference, described by the centre of mass of a satellite or other object in space subjected primarily to natural forces, mainly the force of gravity.
inclination of an orbit (of an earth satellite): The angle determined by the plane containing the orbit and the plane of the Earth’s equator measured in degrees between 0º and 180º and in counter-clockwise direction from the Earth’s equatorial plane at the ascending node of the orbit.
period (of a satellite): The time elapsing between two consecutive passages of a satellite through a characteristic point on its orbit.
altitude of the apogee or of the perigee: The altitude of the apogee or perigee above a specified reference surface serving to represent the surface of the Earth.
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; by extension, a satellite which remains approximately fixed relative to the Earth.
geostationary-satellite orbit: The orbit of a geosynchronous satellite whose circular and direct orbit lies in the plane of the Earth's equator.
steerable satellite beam: A satellite antenna beam that can be re-pointed.
Wave polarization: The orientation of electric field wave vector respect to a given direction.
Monitoring station: An equipped station for doing measurement and investigation of received electromagnetic wave characteristics and authority.