全球定位系统外文翻译.doc

外文翻译原文
Summarizing The Global Positioning System
Abstract: Global Positioning System is based on the background of the United States
Department of Defense .It is designe, invested, developed, and operated by the United States Department of Defense ,GPS is a satellite-based positioning and time transfering ,GPS positioning function has a wide range of applications in the modern measurement and a more modern building. GPS-RTK technology is also widely used in modernization building, and now GPS has also been shown to be an important munities of interest, and increasingly wide range of applicated. Keyword: GPS, Locating,RTK,Lay out,Survey
1. Background
The 50s, the former has not launched humanities first artificial earth satellite, the American scientists in along its track research in, had discovered the Doppler shift phenomenon, and has facilitated Doppler satellite navigation positioning pleting using this principle, has obtained the enormous ess in the military and the civil aspect, was in a navigation localization history leap, our country once has also introduced many Doppler receiver, applied to the island association measured, the Earth explored and so on the applied to the island association measured, the Earth explored and so on the domain. But because Doppler satellite orbit highly low, signal-carrier frequency low, the track precision enhances with difficulty, causes the pointing accuracy lowly, satisfies the geodetic survey or the project survey request, is more impossible to use in the astronomy Earth dynamics research. In order to enhance the satellite positioning the precision, US started from 1973 to prepare for construction global positioning system GPS (Global Positioning System).After has entered the plan proof, the system test stage, started in 1989 to launch the official work satellite, pleted in 1994, investment use. The GPS system space posed by twenty one satellites, evenly distributes in six orbit, the ground level is 20,000 Kil