China has launched the first of its most powerful generation of navigational satellites as part of efforts to expand the global reach of its rival to GPS and to cut reliance on overseas systems.
The launch of the two Beidou-3 satellites in Sichuan on 5th Nov 2017 after months of delays represents the start of a major upgrade to China's home-grown navigational strength.
The satellites are among more than 30 China plans to send up over the next three years to create a network that will be able to support military operations around the world without relying on competitors such as the US-developed GPS or Russia's GLONASS.
There are already more than 20 earlier Beidou versions in orbit but their coverage is limited to China and the region.
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The expanded system will also have a wide range of civilian applications, from smartphones to self-driving cars.
Scientists involved in the project also said the new system would give civilian users an accuracy of 2.5 metres to five metres, putting it on a par with existing GPS technology.
The Chinese military and some government users would be able to use encrypted signals for millimetre precision, the scientists said.
China has built more than 1,500 Beidou ground stations across the country to improve the system's accuracy. It also plans to set up similar bases in dozens of countries including Pakistan and Thailand to extend the high-precision service to military and government users overseas.
