——第二步，建设北斗二号系统。2004年，启动北斗二号系统工程建设；2012年年底，完成14颗卫星（5颗地球静止轨道卫星、5颗倾斜地球同步轨道卫星和4颗中圆地球轨道卫星）发射组网。北斗二号系统在兼容北斗一号技术体制基础上，增加无源定位体制，为亚太地区用户提供定位、测速、授时、广域差分和短报文通信服务。
——第三步，建设北斗全球系统。2009年，启动北斗全球系统建设，继承北斗有源服务和无源服务两种技术体制；计划2018年，面向“一带一路”沿线及周边国家提供基本服务；2020年前后，完成35颗卫星发射组网，为全球用户提供服务。
- The second step is to construct the BDS-2. The project was started in 2004, and by the end of 2012 a total of 14 satellites - 5 GEO satellites, 5 Inclined Geosynchronous Satellite Orbit (IGSO) satellites and 4 Medium Earth Orbit (MEO) satellites - had been launched to finish the space constellation deployment. Based on a technical scheme which was compatible with the BDS-1, the BDS-2 added the passive-positioning scheme, and provided users in the Asia-Pacific region with positioning, velocity measurement, timing, wide-area differential and short message communication services.
- The third step is to construct the BDS. The project was started in 2009 to inherit the technical schemes of both active and passive services. The goal is to provide basic services to the countries along the Belt and Road and in neighboring regions by 2018, and to complete the constellation deployment with the launching of 35 satellites by 2020 to provide services to global users.
（二）北斗系统的基本组成
北斗系统由空间段、地面段和用户段三部分组成。
——空间段。北斗系统空间段由若干地球静止轨道卫星、倾斜地球同步轨道卫星和中圆地球轨道卫星三种轨道卫星组成混合导航星座。
(II) Main Composition of the BDS
The BDS is mainly comprised of three segments: space segment, ground segment and user segment.
- The space segment. The BDS space segment is a hybrid navigation constellation consisting of GEO, IGSO and MEO satellites.
——地面段。北斗系统地面段包括主控站、时间同步/注入站和监测站等若干地面站。
——用户段。北斗系统用户段包括北斗兼容其他卫星导航系统的芯片、模块、天线等基础产品，以及终端产品、应用系统与应用服务等。
（三）北斗系统的发展特色
- The ground segment. The BDS ground segment consists of various ground stations, including master control stations, time synchronization/uplink stations, and monitoring stations.
- The user segment. The BDS user segment consists of various kinds of BDS basic products, including chips, modules and antennae, as well as terminals, application systems and application services, which are compatible with other systems.
(III) Characteristics of the BDS
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