A Long March 3B rocket launched the pair from the Xichang Space Centre at 2110 UTC on 22 September (0510 local on 23 September).
The satellites - the 47/48th BeiDou satellites to have been launched - are reported to have successfully been placed into their targeted medium Earth orbits (MEO).
These satellites are the first in the constellation to be equipped with hydrogen maser clocks, serving as more stable precision frequency references; they are also equipped with updated processors.
Ten further BeiDou satellites are scheduled for launch this year.
The ultimate system will comprise 27 satellites in MEO, 5 geostationary (GEO) and 3 in inclined geosynchronous orbit (IGSO). Currently providing regional cover at ~10m accuracy, global Full Operational Capability (FOC), with improved accuracy, is scheduled for 2020.