China has completed its BeiDou Navigation Satellite System (卫星导航系统), or BDS, becoming another one in the world with a global (全球的) navigation network, the other three being GPS of the US, GLONASS of Russia and Galileo of the European Union.
As the name suggests, the global navigation satellite system provides navigation and location services 24 hours a day. From what we have known so far, building a good satellite system costs a lot. Why does China have a new one if there is nothing special?
The other three systems have 24 satellites in MEO. Besides the 24 satellites, China’s new global navigation satellite system BeiDon-3 also has three satellites in GEO and three in IGSO. What’s special about these six satellites is that they have a relatively fixed area of activity. This can improve BDS’ accuracy (精准度) in China and the Asia-Pacific region to 5 meters, compared with a 10-meter accuracy in other areas.
BDS has another advantage - the short message service. It allows users to have a two-way communication. In areas not covered by communication signals (信号), BDS can make the short message service available in uninhabited areas, such as deserts, forests, mountainous and polar areas. With this service, users who are in danger can tell the rescue team (救援队) their location and condition.
In fact, BDS is also good business. According to the official report, China’s satellite industry has kept a 20% annual growth since 2012. And BDS contributes (贡献) about 80% of it. BDS has also created countless high-paying jobs. And with continuous improvement, it will have much more to offer in the future.
【小题1】BDS is the ________ global navigation network in the world.| A．third | B．fourth | C．fifth | D．sixth |
| A．24 | B．27 | C．30 | D．36 |
| A．A place that is very high | B．A place with lots of animals |
| C．A place impossible to get to | D．A place with no people living in it |
| A．It can only be used in China. |
| B．It is good for China’s development. |
| C．It has made lots of people lose their jobs. |
| D．It doesn’t work in areas where there is no communication signal. |
