Garmin GPS 38 - Manual (Page 6)

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The GPS 38 is a powerful navigation tool that can guide
you anywhere in the world. To better understand its opera-
tion and capabilities, it may be helpful to review the basic
terms and concepts briefly explained below.
Other navigation and GPS definitions used in the man-
ual are defined in the appropriate sections of the reference
section of the manual.
Almanac Data—Satellite constellation information (including location and health of
satellites) that is transmitted to your receiver from every GPS satellite. Almanac data
must be acquired before GPSnavigation can begin.
Bearing—The compass direction from your position to a destination.
Course Made Good (CMG)—The bearing from the “active from” position (your start-
ing point) to your present position.
Crosstrack Error (XTE)—The distance you are off a desired course in either direction.
Desired Track (DTK)—The compass course between the “from” and “to” waypoints.
Differential GPS (DGPS)—An extension of the GPSsystem that uses land-based 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—A 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—A north/south measurement of position perpendicular to the earth’s polar
axis.
Longitude—An east/west measurement of position in relation to the Prime Meridian, an
imaginary circle that passes through the north and south poles.
Navigation—the process of traveling from one place to another and knowing where
you are in relation to your desired course..
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 receiver’s memory.
I N T R O D U C T I O N
Glossary
GPS 38 Man Rev B 7/23/98 4:31 PM Page 2