How Does The Navigation System Work - VDO MS 4100 User Manual

GENERAL INFORMATION

How does the navigation system work?

The VDO Dayton Navigation Radio is a high-performance tool for assisting the driver
in everyday traffic. With automatic route planning and directional guidance you can
concentrate on the essentials on today's increasingly congested roads – especially in
urban areas. Complicated and time-consuming planning with conventional road and
city maps is no longer required. Simply enter the destination before beginning your
journey, activate "Guidance" and the VDO Dayton Navigation Radio does everything
else for you.
The VDO Dayton Navigation Radio provides you with visual and acoustic driving
information. The system is easy to operate with few control elements and a clearly
structured menu.
Determination of vehicle position
60 80 100
40 120
20 140
0 160
Speedometer
Navigation
signal
computer
map. However, the signal provided by the GPS satellites is required in order to correct
the data over a longer period of time.
GPS (Global Positioning System)
The GPS system is based on the reception of navigation
signals from 27 GPS satellites which orbit the earth at
an altitude of 21,000 km in approximately 12 hours.
The signals from at least 4 satellites are needed for
three-dimensional positioning, i.e. determination by
latitude, longitude and altitude. The achievable
accuracy lies within 30 m to 100 m. If the signals of
only three satellites can be received, only two-
dimensional positioning is possible without
determination of the altitude. The accuracy of
the calculated position is thus diminished.
Altogether, the integrated GPS receiver can receive the
signals of up to 8 satellites at the same time.
16
Gyroscope
GPS signal
Digital roadmap
The position and movements of the vehicle
are recorded by the navigation system's
sensors. The distance travelled is determined
by an electronic speedometer signal, rotary
motion in curves is detected by the gyroscope
(inertial compass). However, the information
provided by these sensors is not always
precise. The sensor values change as a result
of wheel slip, changes in the tyre pressure
due to temperature variations, etc. It is
possible to correct sensor inaccuracies over
a certain period of time (several minutes)
by comparing the signals with the digital