天上的北斗
What is BeiDou, China’s GPS?
Name: ________________ Date: ________
很久以前，晚上在野外走路的人，会抬头找七颗很亮的星星，它们连起来像一把勺子。这就是“北斗七星”。顺着它们，就能找到北方。
今天，中国把自己的卫星导航系统也叫作“北斗”。它和美国的全球定位系统做的是一样的事：告诉你，你现在在地球上的什么地方。
为什么中国要自己做一个？因为导航不只是用来开车找路。飞机、轮船、银行、电网，都需要非常准的位置和时间。如果全靠别的国家的系统，一出问题，影响就很大。
北斗不是一年就建好的。二零零零年，中国发射了第一批北斗卫星，那时候只能用在中国附近。二十年后，二零二零年，北斗系统全部建成，全世界都能用了。
现在，北斗就在很多人身边。很多手机能同时收到北斗和美国系统的信号；送外卖的小哥靠它找到你家的楼；农民用它让拖拉机自己在地里走直线；海上的渔船用它报告自己在哪里。
你的手机能用北斗吗？你可以在手机的设置里找一找。
Key words
| Word | Pinyin | Meaning |
|---|---|---|
| 抬头 | táitóu | to raise one's head |
| 亮 | liàng | bright; shiny; to shine; to light up |
| 星星 | xīngxing | star (in the sky) |
| 叫作 | jiàozuò | to be called; to be known as |
| 地球 | dìqiú | the earth; globe |
| 用来 | yònglái | to be used for |
| 准 | zhǔn | accurate; exact |
| 全 | quán | whole; all; entire; complete; completely; entirely |
| 全部 | quánbù | all; whole; entire; completely |
| 同时 | tóngshí | at the same time; simultaneously |
| 信号 | xìnhào | signal |
| 颗 | kē | classifier for small round things (grains, pearls, teeth, hearts, stars) |
English (for the teacher)
Long ago, people walking in the wild at night would look up for seven very bright stars that join up like a ladle. That is the Big Dipper, the “Beidou seven stars”. Follow them, and you can find north.
Today, China calls its own satellite navigation system “BeiDou” too. It does the same job as America’s GPS: it tells you where on Earth you are right now.
Why did China build its own? Because navigation isn’t only for finding your way in a car. Planes, ships, banks and power grids all need very precise positions and times. If you rely entirely on another country’s system, any problem has a big impact.
BeiDou wasn’t built in a year. In 2000, China launched its first BeiDou satellites, which could only be used around China then. Twenty years later, in 2020, the whole BeiDou system was finished, and the entire world could use it.
Now BeiDou is all around many people. Many phones can receive BeiDou and American GPS signals at the same time; delivery riders rely on it to find your building; farmers use it to make tractors drive straight lines by themselves; fishing boats at sea use it to report where they are.
Can your phone use BeiDou? You can look for it in your phone’s settings.