How Does The Navigation System Work - Audiovox NPC5000 User Manual And Mounting Instructions

How does the navigation system work?

Determination of vehicle position
Data from these sensors, in conjunction with positional information received from
the Global Positioning System is transmitted to the navigation computer. The
resultant calculated position is then compared against the road network data stored
on the CD-ROM in order to display the current vehicle position.
GPS (Global Positioning System)
The Global Positioning System is based on the reception of
navigation signals from a total of 27 GPS satellites at a
height of 13,000 miles.
When the vehicle is parked for a long period of time, the satellites change their
orbital positions. Therefore, when the ignition is turned on again it can take a few
minutes before the Navigation System can pick up enough satellites and evaluate the
received signals.
The movement of the vehicle is measured
by sensors that are integrated into the
Navigation System. The distance driven is
recorded by an electronic signal from
the speedometer and the rotary
movements of turns by the gyroscope (a
rotary measurement system). The
information from these sensors is, however,
not always exact as the values can be
affected by tire slippage, varying tire
pressure due to changes in temperature,
etc.
To determine the position with sufficient
accuracy, signals from at least 4 satellites must
be received.
The integrated GPS receiver can handle up to 8
satellite signals simultaneously. This allows an
accuracy of about 20 ft to 60 ft which is further
improved by the other sensors.
General Information
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