摘要
Preface The BeiDou Navigation Satellite System （hereinafter referred to as the BDS） has been independently constructed and operated by China with an eye to the needs of the country＇s national security and economic and social development. As a space infrastructure of national significance, the BDS provides all-time, allweather and high-accuracy positioning, navigation and timing services to global users,
北斗卫星导航系统（以下简称北斗系统）是中国着眼于国家安全和经济社会发展需要，自主建设、独立运行的卫星导航系统，是为全球用户提供全天候、全天时、高精度的定位、导航和授时服务的国家重要空间基础设施。
