Garmin GPS 38 - Manual (Page 9)

Initializing Your GPS for First Time Use
The GPS 38 calculates your position and movement by
tracking signals sent from GPS satellites. Each of the 24
GPS satellites circle the earth twice a day in a very precise
orbit, and transmit information back to earth. In order to
determine a position fix, your GPS receiver needs to contin-
uously “see” at least three satellites.
Because a GPS receiver can only see satellites above the
horizon, it needs to know what satellites to look for at any
given time. By using an almanac (a timetable of satellite
numbers and their orbits) stored in the receiver’s memory,
the GPS 38 can determine the distance and position of any
GPS satellite.
To use this almanac data, your GPS needs to know
where you are, or be given the opportunity to “find itself”.
Once you initialize the unit to this position, the GPS 38
will usually compute a fix within a few minutes.
Remember, this process is only necessary under the
following conditions:
• First time use from the factory.
• The receiver has been moved over 500 miles from
the last calculated position with power off.
• The receiver’s memory has been cleared and all
stored data has been lost.
G E T T I N G
S TA R T E D
Initialization
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GPS 38 Man Rev B 7/23/98 4:31 PM Page 5