Другое: текст по английскому (GPS)

Перевод у статьи отсутствует, по-этому в качестве примера часть текста английской статьи:

The Navigation Satellite Timing and Ranging (NAVSTAR) Global Positioning System (GPS) is a network of orbiting satellites that can be used to provide information on the location of a signal receiver on the earths surface. The system has the potential to revolutionize the practice of surveying and navigation, and investigations and applications to date give some truth to this prediction.
It its simplest form a signal receiver on the surface of the Earth (say mounted on a surveyors tripod, on a boat, or in an aircraft) receives signals from the satellites that enable the distance (or range) from the satellite to the receiver to be determined. If 4 of these distances can be measured, then the three dimensional location of the receiver can be determined with respect to the satellites, and if the positions of the satellites can be determined then absolute location can be derived. This can be performed in a matter of minutes in a hand-held receiver for less than $1000AUD, or to around centimeter precision using more sophisticated (and hence more expensive) instruments.
The availability of the system now means that anybody can determine a unique location on the surface of the planet or navigate across it, not just those lucky few learned in the black arts of astronomy and geodetic positioning (that is, Geomatics professionals). Yacht owners, bush walkers, 4 wheel drivers, BMW Series 7 owners, ambulances, CFA fire tenders, fliers, explorers, inhuman Serbian snipers, Polaris missiles, the French Marines, Greenpeace and techno-junkies all now have access to positioning information previously unavailable.
The topic of GPS will be dealt with in these notes at a very introductory level. These reference notes are designed to accompany a course inplane surveying, whereas GPS positioning takes place on a complex surface which can be only approximately modelled by a spheroid. In order to understand fully the solution to GPS positioning a high level of geodetic and mathematical knowledge is required. This will be provided in the later years of the Geomatics courses.