In ancient times， our ancestors relied on stars to guide them on a clear night. Today， we have navigational systems to help us find our way， with the latest being the Beidou Navigation Satellite System （BDS）.

The BDS is entirely built by Chinese engineers. The global network of 59 satellites has been completed. Beidou has started providing full-scale global services.

When you unlock one of Hellobikes bicycles， you are using the BDS. Users can find shared bikes more accurately thanks to Beidous global positioning accuracy of 2.34 meters.

However， the BDS doesnt just work one way. As the countrys largest space-based system and one of four global navigation networks， along with the United States GPS， Russias GLONASS and the European Unions Galileo， Beidou adopts a unique two-way communication system， including its ability to receive messages sent by people from areas with poor communication signals. Obviously， this exclusive function isnt designed for users to chat online. Instead， it plays a role when disasters occur and communications are blocked.

Now， Beidous messaging capacity has been increased to 1，200 Chinese characters in a single message. It is widely used in disaster alarms， automatic identification and information release.

As Sun Jiadong， former chief designer of the BDS said， “The application of Beidou is only limited by imagination.”

古时候，我们的祖先通过观测晴朗夜空中的星星来指引方向。如今，我们拥有了能够帮助我们识路的导航系统，其中最新的技术便是北斗卫星导航系统。

北斗卫星导航系统完全由中国工程师研发建设。由59颗卫星组成的全球网络已全部部署完成。北斗卫星导航系统已经开始提供全方位的全球服务。

当你解锁一辆哈啰单车时，你便在使用北斗卫星导航系统。由于北斗系统全球实测定位精度均值为2.34米，用户们能更准确地找到共享单车的位置。

但北斗系统并非只提供单向服务。作为我国最大的航天系统，也是全球四大导航系统之一（其余三个分别为美国全球定位系统、俄罗斯格洛纳斯、欧盟伽利略），北斗系统采用了一种特有的双向通信系統，能够接收通信信号欠佳地区的人们发送的信息。显然，这一独有的功能并非用于用户线上聊天，而是在灾难发生、通信受阻时发挥作用。

如今，北斗系统的短报文通信能力提升到一次1 200个汉字，被广泛应用于灾难预警、自动识别以及信息发布。

正如北斗卫星导航系统前任总设计师孙家栋院士所言：“北斗的应用只受想象力的限制。”

Word Study

exclusive /?k'sklu?s?v/ adj. 专有的;专用的

The hotel has exclusive access to the beach.

release /r?'li?s/ n. 发行;发布

The new software is planned for release in April.