SHANGHAI, June 5 (China Space News) -- China will launch some 18 Beidou navigation satellites by 2018, a leading navigation satellite expert said Tuesday.

Six to eight Beidou satellites will be sent into orbit in the second half of this year. The Beidou satellite navigation system will be able to provide services for countries participating in the Belt and Road Initiative by 2018.

By 2020, the Beidou satellites will form a complete global satellite navigation system.

The output value of China's satellite navigation and locating services totaled 210 billion yuan (30.5 billion U.S. dollars) in 2016, with the Beidou system contributing more than 30 percent of the total value.

The sector is forecast to have about 400 billion yuan in annual output value by 2020.

China started building its own satellite navigation system in 2000 when it sent two orbiters into space as a double-satellite experimental positioning system in order to end its dependence upon the U.S. GPS system.

Since 2012, Beidou has provided navigation, time and text messaging services in the Asia and Pacific region.