As part of its domestic satellite navigation system rivalling the GPS, China launched two new satellites into space on Saturday (25 July).

They were launched from the Xichang Satellite Launch Centre in southwestern Sichuan province, said the official Xinhua news agency.

The new satellites will be deployed in "testing a new type of navigation signalling and inter-satellite links" besides providing navigation services.

In all, the navigation system Beidou, or Compass, now has 19 satellites and mostly centres on the Asia Pacific, but is expected to cover the planet by 2020.

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

Beidou – named after the Chinese term for the Big Dipper constellation – joins the US's GPS, Russia's GLONASS and the European Union's Galileo systems.

It is already used by several Asian countries including Laos, Pakistan and Thailand.

Currently, it's used for civilian services, such as navigation and messaging, and weather forecasting sectors, but Beidou also has military applications.

China recently announced the commencement of work on the world's largest radio telescope meant to scour outer space for signs of extraterrestrial life.

Work began on the telescope's reflector which spans 500m in diameter and is built of 4,450 panels.