In December 2012, the system began providing positioning, navigation, timing and messaging services to civilian users in China and parts of the Asia-Pacific region.

China plans to place 18 third-generation Beidou satellites in space before the end of the year.

They will work with earlier-generation models to provide services for all the nations involved in the Belt and Road Initiative, the navigation office said.

The initiative is a far-reaching infrastructure plan proposed by President Xi Jinping in 2013.

It comprises the Silk Road Economic Belt, which will link China with Europe through Central and Western Asia, and the 21st Century Maritime Silk Road, which will stretch from southern China to Southeast Asia and Africa.

The initiative will benefit about 4.4 billion people in 65 nations, according to government estimates.

At present, the Beidou system covers about 30 countries participating in the initiative, including Pakistan, Egypt and Indonesia, the navigation office noted.

Next year, and in 2020, China will place six third-generation Beidou satellites in medium Earth orbits, along with three in inclined geosynchronous satellite orbits and two to geostationary orbits.

According to plans drawn up by the China Satellite Navigation Office, the network will comprise 35 satellites before the end of 2020 - several currently in orbit will be decommissioned by then - allowing Beidou to provide global coverage.

Once the network is completed, it will provide civilian users around the world with free navigation and positioning services to an accuracy of about 10 meters.

However, paying customers will be provided with services that will be accurate to about a centimeter.