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Nanosecond One billionth of a second. National Administrations The expression National Administration(s) is to be understood as to include public, corporate and/or private entities within ECAC Member States providing civil and/or military Air Navigation Services. National Oceanic and Atmospheric Administration Also, a series of polar.orbiting weather satellites operated by NOAA. Natural Sequence A sequence of flights calculated for controller planning purposes based on estimate time at the constraint point using first-come-first-served principle. Nautical Mile A measure used in navigation. The unit is equal to 1852 m. Navigation The means by which an aircraft is given guidance to travel from one known position to another known position. The process involves referencing the actual aircraft position to a desired course. Navigation Control System to determine actions to be taken to follow a planned route. Currently 2D, 3D and 4D navigation, are in use. Using 2D-navigation, a 2D-route (set of geographical co-ordinates) can be flown. 3D-Navigation makes it possible to assure a certain altitude for each geographical position. Some modem aircraft already use 4D-navigation, where it is also possible to guarantee reaching a specific point and altitude at a specified time. Navigation Guidance The calculation of steering commands to maintain the desired track from the present aircraft position to a new position. Navigation Information The calculation and display of aircraft present position, velocity vector and related data, such as track angle, ground speed and drift angle. Navigation System Data Base An ARINC Standard for content and format of Navigation Data stored in Airborne Flight Management Systems. Navigation System Error See Sum (of errors).
The accuracy of the system employed to determine the aircraft position relative to a pre-defined co-ordinate system. NSE is defined at the output of the navigation receiver and represents the sum of the following navigation system components: source, signal-in-space, airborne processing and airborne computational element.