China has successfully launched a pair of navigation satellites to expand the nation's Beidou (Compass) system to global coverage.
The launch is the 33rd the country has undertaken this year and the ninth contributing to the Beidou project.
The four-hour mission placed the satellites in medium Earth orbit (MEO) on the back of one of China's Long March rockets.
Launching from Sichuan Province, at the Xichang Satellite Launch Centre, the satellites are smaller than a car - measuring 2.25m by 1.22m by 1m.
They will form part of the Beidou Navigation Satellite System (BDS) which the Chinese government has designed and constructed to meet its own national security standards.
The BDS has been classed as providing 95% accuracy within six metres horizontally, and 95% accuracy within 10 metres vertically.
Navigation satellites are generally considered a shared global resource - with the American Global Positioning System (GPS) being among the most widely used.
A rival to GPS is being developed by the EU, called Galileo, and in the face of the UK potentially being frozen out of the Galileo project the prime minister announced that the country will develop its own satellite system.
While the satellite navigation systems are considered a public resource, the nations that operate them often reserve the most accurate bands of measurement for their own military uses.
Interference in GPS signals has become a significant threat for military forces and traditional map-reading and non-digital navigational skills are being stressed following suggestions that hostile nations are developing the capabilities to disrupt satellite navigation.
Earlier this month the Finnish prime minister suggested that air navigation services across the country had been interrupted by the Russian Federation due to a NATO exercise.
Russia denied the accusation, but had previously threatened to harm satellite navigation and on-board radars of combat aircraft which attacked target in Syria, following an apparent "friendly-fire" incident.