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CHANGSHA, May 19 -- China plans to launch 30 Beidou navigation satellites during the 13th five-year plan period (2016-2020), capping its three-step strategy to build a global navigation system by 2020.

The first batch of 18 satellites will be launched before 2018 to cover countries along the routes in "the Belt and Road" initiative, said Ran Chengqi, director of the China Satellite Navigation Office, during the China Satellite Navigation Conference, which opened on Wednesday.

After having achieved the first two steps -- building a regional functional navigation system by 2012, the accuracy and stability of the Beidou system must be improved, said Ran, adding international cooperation will also help the nascent navigation system.

Aside from announcing satellite navigation cooperation with the United States, China and Russia have agreed to make the Beidou and Glonass satellite navigation systems compatible with each other, said Ran.

He added that Beidou also successfully synchronized its frequency with the Galileo navigation system operated by the European Union.

Ran said China will detail the development ideas and proposals of the Beidou system in a white paper, which is expected to be released soon.

The white paper also elaborates on how Beidou will work with the International Civil Aviation Organization and International Maritime Organization to bring benefits to the world, according to Ran.

"To let the whole world know about Beidou, understand Beidou and use Beidou, we still have much technical and coordination work to do," he said.