GNSS	Global Navigation Satellite System
BDS	BeiDou Navigation Satellite System
GPS	Global Positioning System
SIS	Signal in space
DQA	Data quality analysis
SQA	Signal quality analysis
MQA	Measurement quality analysis
GLONASS	Global Navigation Satellite System
QZSS	Quasi-Zenith Satellite System
MEO	Medium Earth orbit
GEO	Geostationary Earth orbit
IGSO	Inclined geosynchronous orbit
CGCS2000	Chinese Geodetic Coordinate System 2000
WGS84	World Geodetic System 1984
BDT	BeiDou Navigation Satellite System Time
UTC	Universal Time
GPST	GPS Time
C/N0	Carrier-to-noise density ratio
RTK	Real-time kinematics