A Long March-4B carrier rocket carrying the Yaogan-21 remote sensing satellite blasts off from the launch pad at the Taiyuan Satellite Launch Center in Taiyuan, capital of north China's Shanxi Province, Sept 8, 2014.[Photo/Xinhua]

XICHANG, Sichuan - China successfully launched two satellites for its indigenous global navigation and positioning network at 8:29 pm Beijing Time Saturday, the launch center said.

Launched from the Xichang Satellite Launch Center in the southwestern China's 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 preset 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.

The successful launch marks another solid step in building Beidou into a navigation system with global coverage, the center said.

The two satellites will join the 17th one, which was launched in late 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, the center said.

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.