Garmin GPS 12 MAP Owner's Manual page 9

The GPS 12 MAP is a powerful navigation tool
that can guide you anywhere in the world. To
better understand its operation and capabilities,
it may be helpful to review the basic terms and
concepts briefly explained below.
Other navigation and GPS definitions used in
this manual are defined in the appropriate refer-
ence sections of this manual.
Almanac Data—Satellite constellation information (including location) that
is transmitted from every GPS satellite. Almanac data must be acquired before
GPS navigation can begin.
Bearing—The compass direction from your position to a destination.
Course Made Good (CMG)—The bearing from the "active from" position
(your starting point) to your present position.
Crosstrack Error (XTK)—The distance you are off a desired course either
left or right.
Desired Track—The compass course between the "from" and "to" waypoints.
Differential GPS (DGPS)—An extension of the GPS system that uses radio
beacons to transmit position corrections to GPS receivers.
Estimated Time of Arrival (ETA)—The time of day of your arrival at a
destination.
Estimated Time Enroute (ETE)—The time left to your destination at your
present speed.
Grid—Coordinate system that projects the earth on a flat surface, using square
zones for position measurements. UTM/UPS and Maidenhead formats are grid
systems.
Ground Speed—The velocity you are traveling relative to a ground position.
Latitude—The north/south measurement of position perpendicular to the
earth's polar axis.
Longitude—The east/west measurement of position referenced to the Prime
Meridian (0° longitude) which goes through Greenwich, England.
Navigation—The process of traveling from one place to another and know-
ing where you are in relation to your desired course and/or destination.
Position—An exact, unique location based on a geographic coordinate system.
Track (TRK)—The direction of movement relative to a ground position.
Universal Transverse Mercator (UTM)—A grid coordinate system that
projects global sections onto a flat surface to measure position in specific zones.
Velocity Made Good (VMG)—The speed you are traveling in the direction
of the destination.
Waypoint—A specific location saved in the GPS receiver's memory.
Glossary
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