资 源 简 介
Of the various applications that satellites have been used for, one of
the most promising is that of global positioning. Made possible by
Global Navigation Satellite Systems, global positioning enables any
user to know his or her exact position on Earth. Nowadays, the only
fully functioning system is the American Global Positioning System
(GPS). However, the European system, known as Galileo, is expected to
be operative in 2012.