Eclipse AVN2454 Owner's Manual page 155

2- and 3-dimensional positioning
Signals do
not intercross
at one point
Position determined by 2-
dimensional measurement
Vibration gyro sensor
This sensor electronically detects in which direction your vehicle turned. This sensor plays
a very important role in the independent navigation function of this device.
The GPS calculates your position using
a 3-point measurement principle.
Signals received from one satellite are
Actual
used determine the distance from that
position
satellite to your vehicle. Signals received
from 3 satellites can pinpoint your
present location.
However, there exists a margin of error
in the GPS satellite and navigation unit
Error
resulting in 2-dimensional positioning
using latitudinal and longitudinal
coordinates if signals from only 3
satellites can be received. In such a
case, accuracy is low.
Also, when receiving signals from 4 or
more
positioning is effectuated using the
latitude, longitude and altitude of your
vehicle. 3-dimensional positioning is
more accurate than 2-dimensional
positioning and the vehicle position
display error margin is reduced.
satellites, 3-dimensional
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