全球卫星导航系统的近期进展

２０世纪末，卫星导航发展势态出现了ＧＬＯＮＡＳＳ星座维持困难，ＧＰＳ推行现代化计划和欧洲Ｇａｌｉｌｅｏ计划出台三大新闻。有望于２０１０年左右Ｇａｌｉｌｅｏ星座和ＧＰＳ星形成互补和卫为余度。最近，美国国会削减ＧＰＳ预算，在ＧＰＳ民用进展上投下阴影，ＧＰＳ单一导航手段暂难实行，有利于欧洲争取时间，积极筹措Ｇａｌｉｌｅｏ系统。

The Progress Recently Made in the Global Satellite Navigation System

The last decade of the 20th century has seen three salient events in the satellite navigation development: the GLONASS has been in trouble maintaining its constellation, the GPS is carrying out its modernization plan and the new Galileo plan is now launched in Europe. It is foreseen that the GPS constellation and the Galileo one may form one complementary and redundant system by the year 2010. The budget cuts by the U.S. Congress may throw a shadow over the advancement of the GPS, but, on the other hand, Europe may take advantage of this to have more time to establish its own Galileo system.