China has completed its BeiDou Navigation Satellite System, or BDS, becoming the fourth country in the world with a global navigation network, the other three being GPS of the U.S., GLONASS of Russia and Galileo of Europe.
As the name suggests, the global navigation satellite system provides navigation and location services on a 24-hour basis.
So, what makes China's BDS stand out among its competitors?
The other systems have 24 satellites in medium earth orbit (MEO). In addition to the 24 satellites, the BDS constellation also has three satellites in geostationary earth orbit (GEO) and three in inclined geosynchronous orbit (IGSO).
What's special about the extra six satellites is that they have a relatively fixed range of activity.
This layout can enhance BDS' accuracy in China and the Asia-Pacific region to five meters, in comparison with a 10-meter accuracy in other areas.
On top of that BDS has a short message service. It is a function that allows users to have a two-way communication.
In areas not covered by cellular or communication signals, BDS can make the short message service available in uninhabited areas, such as deserts, forests, and mountainous or polar regions.
With this service, users in distress can inform the rescue team about their location and condition.