時間：2011-08-27 23:38來源：藍天飛行翻譯 作者：航空 點擊：次
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World Aeronautical Chart A chart used to provide information to satisfy the requirements of visual air navigation which is in conformance with the international standards and recommended practices detailed in Chapter 16 of Annex 4 to the Convention of International Civil Aviation. World Area Forecast Centre A meteorological centre designated to prepare and supply upper-air forecasts in digital form on a global basis to regional area forecasts centres. World Area Forecast System A world-wide system by which world and regional area forecasts centres provide aeronautical meteorological en-route forecasts in uniform standardised formats. World Geodetic Survey Well-defined universal co-ordinate system applicable unambiguously to all points and routes of aeronautical significance over the whole terrestrial globe, independently of the local gravity field. World Geodetic System A consistent set of parameters describing the size and shape of the Earth, the positions of a network of points with respect to the centre of mass of the Earth, transformations from major geodetic datum, and the potential of the Earth (Usually in terms of harmonic coefficients). See Standard Geodetic System. World Geodetic System 1984 WGS 84 is an ellipsoid designed to fit the shape of the entire Earth as well as possible with a single ellipsoid. It is often used as a reference on a worldwide basis, while other ellipsoids are used locally to provide a better fit to the Earth in a local region. GPS uses the centre of the WGS-84 ellipsoid as the centre of the GPS ECEF reference frame. World Radio-communications Conferences The ITU Radio Regulations constitute an international treaty on radio communication covering the use of the radio-frequency spectrum by radio-communication services. WRCs may : a) Revise the Radio Regulations and any associated Frequency Assignment and Allotment Plans; b) Address any radio-communication matter of world-wide character; c) Instruct the ITU Radio Regulations Board and the ITU Radio-communication Bureau, and review their activities; d) Determine Questions for study by the ITU Radio-communication Assembly and its Study Groups in preparation for future Radio-communication Conferences. WRCs are normally convened every two years. The general scope of the agenda is set by a WRC four years in advance of the conference. The final agenda is set by the ITU Council, preferably two years in advance. Worst Probable Position (MTCD) Probable position of an aircraft at the time of a conflict, for which the separation criteria are violated most.
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