These are the most common keywords you will hear relating to the various GNSS, IRNSS and QZSS satellite systems.
Almanac
Almanac data is information that describes satellite orbital courses.
This data can be used to calculate the approximate location of a satellite, or satellites orbit.
GPS receiver can almanac data to predict which satellites are nearby when they’re looking for GPS signals.
ADEV
Allan deviation
AFS
atomic frequency standard
BC
Barker code
BIH
Bureau International de l’Heure
BIPM
Bureau International des Poids et Mesures
BPSK
binary phase-shift keying
CDMA
code division multiple access
CNAV
civil navigation message
CRC
cyclic redundancy check
DGPS
A Differential Global Positioning System is an enhancement to the Global Positioning System which provides improved location accuracy, in the range of operations of each system, from the 15-meter nominal GPS accuracy to about 1–3 cm in case of the best implementations.
DLR
Deutsches Zentrum für Luft- und Raumfahrt
ESA
European Space Agency
FDMA
frequency division multiple access
GIOVE
Galileo In-Orbit Validation Element
GLONASS
Global’naya Navigatsionnaya Sputnikova Sistema (Russian Global Navigation Satellite System)
GLST
GLONASS System Time
GNSS
global navigation satellite system
GPS
Global Positioning System
HDOP
horizontal dilution of precision
Relates to the horizontal position measurements suggested by GPS data. PDOP (positional dilution of precision) is most widely presented value in GPS receivers.
ICAO
International Civil Aviation Organization
ICD
interface control document
IERS
International Earth Rotation and Reference Systems Service
IGS
International GNSS Service
ITRF
International Terrestrial Reference Frame
ITRS
International Terrestrial Reference System
ITU
International Telecommunication Union
LEO
low Earth orbit
LEOP
launch and early orbit phase
LRA
laser retro-reflector array
MEO
medium Earth orbit
NH
Neuman-Hofman (code)
NUDET
nuclear detection (payload)
PDOP
position dilution of precision
PRN
pseudo-random noise
RFSA
Russian Federal Space Agency
RMS
root mean square
RSSI
Received Signal Strength Indicator.
Is a measurement of how well your device can hear a signal from an access point or router. It’s a value that is useful for determining if you have enough signal to get a good wireless connection.
SDCM
System for Differential Corrections and Monitoring
SISRE
signal-in-space range error
SLR
satellite laser ranging
UTC
Coordinated Universal Time