NorthStar MX500 Operator's & Installation Manual page 263

Glossary
GEOGRAPHIC COORDINATES
GEOID
GEOIDAL HEIGHT
GDOP (Geometric Dilution of Precision)
GFSK
GMSK
GNSS
GLOBAL POSITIONING SYSTEM (GPS)
GLONASS
Version 3.0
Angular displacements along parallels of latitude and meridians of
longitude on an ellipsoidal surface. Ellipsoidal coordinates.
The Earth's surface with all topographical undulations removed
(equipotential surface) so that all points on the surface approxi-
mate mean sea level.
Deviations of the geoid above and below the ellipsoid due to non-
uniformity of the Earth's mass. Geoidal height is positive when the
deviation is outward from the central volume of the ellipsoid, and
negative when it is inward.
An indicator of the accuracy in position (latitude, longitude, alti-
tude, and time). See DILUTION OF PRECISION.
Gaussian-Filtered-Shift-Keying – A standardized method of
modulating digital data prior to transmission on a data link.
Gaussian-Minimum-Shift-Keying – GFSK using BT-products and
modulation index which optimizes the modulated signal.
Global Navigation Satellite System – A common label for satellite
navigation systems (such as GPS and GLONASS).
The NAVSTAR Global Positioning System, which consists of or-
biting satellites, a network of ground control stations, and user
positioning and navigation equipment. The system has 24 satel-
lites plus 3 active spare satellites in six orbital planes about 20,200
kilometers above the earth.
A satellite navigation system developed and operated by
Russia.
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