Two navigation satellites, Beidou 3M-6S and Beidou 3M-7S, were launched by China at 2318 GMT on 11 January 2018. The launch of the satellite pair was by the Long March 3B/YZ-1 which was flying from its usual Xichang launch site. The 1,014kg satellites were built by the SECM – Shanghai Engineering Center for Microsatellites. They will be used as part of the Beidou (Compass) constellation which is roughly equivalent to the US GPS system. The satellites, which are owned by the Chinese military, have been placed positions in a roughly circular 21,500km Medium Earth Orbit (MEO) at 55 degrees inclination.