A U D I O E Q U I P M E N T a n d T E L E M A T I C S
XI
172
NAVIGATION-GUIDANCE
What is the navigation system and
the GPS?
The satellite navigation system guides
the driver to the destination that he has
set in accordance with a chosen route.
Initially, it searches for the destination
required by the user, then it calculates
t h e r o u t e a n d fi n a l l y i t p r o v i d e s t h e v i s u a l
and audible guidance instructions. What precautions should be
observed in order to use the system
under good conditions?
Do not place anything on or near the
GPS aerial.
Do not use any digital communication
equipment (personal computers, etc.)
near the GPS aerial.
D o n o t a f fi x a n y r e fl e c t i v e fi l m s o r fi l m s
containing carbon to the window.
The GPS (Global Positioning
System) consists of several
satellites distributed around
the earth. They continuously
transmit digital signals
which travel at the speed of light, on 2
different frequencies.
At any given time, the system receives
its position in relation to the satellites
detected and the time of transmission
of the signal.
This enables the telematic unit to
deduce its position and therefore that of
the vehicle.
A repositioning process using the
map database stored on the hard disc
permits repositioning of the vehicle’s
position on the road network in order
to improve the accuracy of the locating
function. What is a point of interest (POI)?
Up to 40 different icons may
be displayed (refer to the
section “Points of interest
icon”).
T h e y a r e c l a s s i fi e d i n
5 g r o u p s a n d i d e n t i fi e d b y o n e c o l o u r
for each group:
- S h o p s , fi n a n c e a n d b u s i n e s s e s (Green),
- Vehicles and travel (Dark blue),
- Restaurants (Orange),
- Public places and emergency services (Brown),
- Entertainment and attractions (Blue).
GPS
The system’s measurements may be
inaccurate if the vehicle is:
- in a tunnel or underground car park,
- underneath a two-level motorway,
- in an area with several very high buildings,
- surrounded by closely planted trees.
Depending on the vehicle’s situation and
the reception of the GPS information, the
displayed information may disappear
from the display temporarily. A point of interest (POI) is
represented by an icon on
the map, it represents an
airport, a station, a town
hall, etc.