China has successfully launched two more satellites, adding to 17 already in orbit, as it builds a homegrown satellite navigation system to rival the US's Global Positioning System.
Launched from the Xichang Satellite Launch Center in the China's southwestern Sichuan Province, the two satellites were the 18th and 19th for the Beidou Navigation Satellite system, China's homegrown navigation system.
They were sent into their present orbits by a Long March- 3B/Expedition-1 carrier rocket 3.5 hours after the launch, the center said.
Expedition-1, or Yuanzheng-1, is an independent aircraft installed on the carrier rocket with the ability of sending one or more spacecraft into different orbits in space, state- run Xinhua news agency said.
"The successful launch marks another solid step in building Beidou into a navigation system with global coverage", the center said.
China is building its own Beidou or Compass global navigation and positioning network to reduce dependence on GPS, specially for its military and marketing abroad. It is already being used in countries like Pakistan, Thailand and Laos.
The two satellites will join the 17th one, which was launched in March, in the mission of testing a new type of navigation signaling and inter-satellite links, and also provide navigation services as a part of the network.
This launch was the 206th flight of China's Long March carriers.
China launched the first satellite for Beidou in 2000.
The Beidou system began providing positioning, navigation, timing and short message services to civilian users in China and surrounding areas in the Asia-Pacific in December 2012.
The system has been gradually put into use in extended sectors including transportation, weather forecasting, marine fishing industry, forestry and telecommunications.
China hopes that its homegrown Beidou satellite navigation system could soon challenge the market share of the US's GPS, Russia's GLONASS and European Union's Galileo by offering much cheaper services.
