BEIJING — Four new satellites of the BeiDou Navigation Satellite System (BDS) have recently passed tests in orbit and joined the system to provide positioning, navigation and timing services.

The four satellites include the 47th, 48th, 52nd and 53rd satellites of the BDS family, according to China's Satellite Navigation System Management Office.

All of them, operating in medium Earth orbit, were developed by the China Academy of Space Technology under the China Aerospace Science and Technology Corporation.

The 47th and 48th BDS satellites were launched on Sept 23, 2019, and the 52nd and 53rd BDS satellites were launched on Dec 16, 2019.

China began to construct its navigation system, named after the Chinese term for the Big Dipper constellation, in the 1990s and started serving the Asia-Pacific Region in 2012.

Over the past two years, China has successfully sent 28 BDS-3 satellites and two BDS-2 satellites into orbit.

China plans to launch more BDS satellites in March and May to complete the global network.