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.”

古時候，我們的祖先通過觀測晴朗夜空中的星星來指引方向。如今，我們擁有了能夠幫助我們識路的導(dǎo)航系統(tǒng)，其中最新的技術(shù)便是北斗衛(wèi)星導(dǎo)航系統(tǒng)。

北斗衛(wèi)星導(dǎo)航系統(tǒng)完全由中國工程師研發(fā)建設(shè)。由59顆衛(wèi)星組成的全球網(wǎng)絡(luò)已全部部署完成。北斗衛(wèi)星導(dǎo)航系統(tǒng)已經(jīng)開始提供全方位的全球服務(wù)。

當(dāng)你解鎖一輛哈啰單車時，你便在使用北斗衛(wèi)星導(dǎo)航系統(tǒng)。由于北斗系統(tǒng)全球?qū)崪y定位精度均值為2.34米，用戶們能更準(zhǔn)確地找到共享單車的位置。

但北斗系統(tǒng)并非只提供單向服務(wù)。作為我國最大的航天系統(tǒng)，也是全球四大導(dǎo)航系統(tǒng)之一（其余三個分別為美國全球定位系統(tǒng)、俄羅斯格洛納斯、歐盟伽利略），北斗系統(tǒng)采用了一種特有的雙向通信系統(tǒng)，能夠接收通信信號欠佳地區(qū)的人們發(fā)送的信息。顯然，這一獨有的功能并非用于用戶線上聊天，而是在災(zāi)難發(fā)生、通信受阻時發(fā)揮作用。

如今，北斗系統(tǒng)的短報文通信能力提升到一次1 200個漢字，被廣泛應(yīng)用于災(zāi)難預(yù)警、自動識別以及信息發(fā)布。

正如北斗衛(wèi)星導(dǎo)航系統(tǒng)前任總設(shè)計師孫家棟院士所言：“北斗的應(yīng)用只受想象力的限制?！?/p>

Word Study

exclusive /?k'sklu?s?v/ adj. 專有的;專用的

The hotel has exclusive access to the beach.

release /r?'li?s/ n. 發(fā)行;發(fā)布

The new software is planned for release in April.