A Long March-3B / Expedition-1 carrier rocket has successfully launched two navigation satellites to join China’s Beidou global navigation network, from the Xichang Satellite Launch Center in the south-western province of Sichuan.

Around three-and-half hours after launch, the the 18th and 19th satellites of the navigation system were placed into their scheduled orbits.

Expedition-1 is an independent aircraft installed on the carrier rocket, designed to send one or more spacecraft into different orbits.

The satellite launch centre was quoted by Xinhua as saying: "The successful launch marks another solid step in building Beidou into a navigation system with global coverage."

"The system was initially launched for positioning, navigation, timing and short message services for Chinese civilian customers."

Earlier this year, the country launched the 17th Beidou satellite in order to test a new type of navigation signalling and inter-satellite link.

Beidou, called the Compass Navigation Satellite System (CNSS), is in competition with the US Global Positioning System (GPS), Russia’s Glonass, and the EU’s Galileo.

The system was initially launched for positioning, navigation, timing and short message services for Chinese civilian customers, as well as the surrounding Asia-Pacific regions.

Subsequently, the service extended to various sectors such as transportation, weather forecasting, the marine fishing industry, forestry, and telecommunications.

Several Asian countries, including Laos, Pakistan and Thailand, are currently using the service. Beidou is expected to serve global markets by 2020.