BEIJING - China's homegrown navigation system BeiDou is expected to achieve full-scale global coverage by around 2020, a leading scientist?said on Sunday.

The BeiDou Navigation Satellite System (BDS) will then be able to provide highly accurate and reliable positioning, navigation and timing service with the aid of a constellation of 35 satellites, said Ye Peijian, chief commander of Chang'e-3, China's lunar probe mission.

"So far, China has successfully launched 16 navigation satellites and four other experimental ones for BDS," Ye said.

China started to build up its own space-based Positioning, Navigation and Timing system in 2000 by launching the first satellite for an experimental version of the BeiDou.

BeiDou has since started providing licensed services for China's government and military users in transport, weather forecasts, fishing, forestry, telecommunications, hydrological monitoring and mapping.

However, it is estimated that more than 95 percent of navigation terminals sold in China are GPS terminals.

To compete with foreign rivals, the BeiDou terminal can communicate with the ground station by sending and receiving short messages, 120 Chinese characters in each, in addition to the navigation and timing functions that the world's other major navigation systems can provide.

BeiDou aims to take 70 to 80 percent of the now GPS-dominated domestic market by 2020, a spokesman for the system said in December.

"We hope that the industries based on BDS will hold 15 to 20 percent of the market share by 2015," said BDS spokesman Ran Chengqi, who is also director of the China Satellite Navigation Office.