Garmin GPS 89 - Manual (Page 9)

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Initialialng the GPS 89 for First-Timt Use
The GPS 89 calculates your position and movement by
tracking signals sent from GPS satellites. Each of the 21
active GPS satellites circles the earth twice a day in a very
precise orbit, and transmits information back to earth. In
order to determine a position fix, your GPS receiver needs to
continuously “see’ at least three satellites.
Because a GPS receiver can only see satellites above the
horiaon, it needs to know what satellites to look for at any
pven time. By using an almanac (a timetable of satellite num­
bers and their orbits) stored in the receiver^ memory, the
GPS 89 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 89 wiQ usually
compute a fix within a few minutes.
Remember, this process is only necessary under the
following conditions:
• Fiist-iime use from the factory.
• The receiver has been moved over 500 miles from
the last calculated position with power off.
• The receiver^ memory has been cleared and all
stored data has been lost.
Because the GPS 89 relies on satellite signals to provide
you with navigation guidance, the receiver needs to have an
unobstructed, clear view of the sky for best performance.
The GPS receiver's view of the sky will generally deiermine
how fast you get a position fix, or if you get a fix at all. GPS
signals are relatively weak, and do not travel throu^ metal,
buildings, people, mountains and other significant struc­
tures, so you iKed to make sure that you’re not standing next
to any obstructions when acquiring satellites.
page will help jwit deter­
mine what satelliCK are In
view, and whether or not
dt^ satellites are being
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the receiver^ antenna.