Garmin NavTalk - Manual (Page 18)

6
SECTION 1
Introduction To
NavTalk
In a nutshell, the GPS receiver’s view of the sky will
generally determine how fast you get a position fix—or if
you get a fix at all. GPS signals are relatively weak and do
not travel through rocks, buildings, people, metal, or
heavy tree cover, so remember to keep a clear view of
the sky at all times for best performance.
Once the NavTalk has calculated a position fix, you’ll
usually have anywhere from five to twelve satellites in
view. The receiver will then continuously select satellites
in view to update your position. If some of the satellites
in view get blocked or “shaded,” the receiver can simply
use an alternate satellite to maintain the position fix.
Although a GPS receiver needs four satellites to pro-
vide a three-dimensional (3D) fix, it can maintain a two-
dimensional (2D) fix with only three satellites. A three-
dimensional fix means the unit knows its latitude, longi-
tude, and altitude, while a two-dimensional fix means the
unit knows only its latitude and longitude.
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