SMShrestha

代码说明：

  The NAVSTAR GPS (NAVigation Satelllite Timing And Ranging Global Positioning System) is an all-weather, space-based navigation system developed by the U.S. Department of Defense to determine ones position, velocity, and time accurately in a common reference system on the Earth. The present constellation consists of nominally 24 satellites and provides global coverage with four to eight satellites simultaneously observed above 15 ? elevation.