AV
NAVIGATION SYSTEM
AV-377
< FUNCTION DIAGNOSIS >
[BOSE AUDIO WITH NAVIGATION]
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Input signals are prioritized in each situation. However, this order of priority may change in accordance with
more detailed travel conditions so that the travel direction is detected more accurately.
MAP-MATCHING
Map-matching repositions the vehicle on the road map when a new
location is judged to be more accurate. This is done by comparing
the current vehicle position (calculated by the normal position detec-
tion method) from the map data stored in the HDD (Hard Disk Drive).
There is a possibility that the vehicle position may not be corrected in the following case, and when vehicle is
driven over a certain distance or time in which GPS information is hard to receive. Correct manually the cur-
rent location mark on the screen.
• In map-matching, several alternative routes are prepared and pri-
oritized in addition to the road judged as currently driving on.
Therefore, due to errors in the distance and/or direction, an incor-
rect road may be prioritized, and the current location mark may be
repositioned to the incorrect road.
If two roads are running in parallel, they are of the same priority.
Therefore, the current location mark may appear on either of them
alternately, depending on maneuvering of the steering wheel and
configuration of the road, etc.
• Map-matching does not function correctly when road on which the
vehicle is driving is new, etc. and not recorded in the map data.
Also, map-matching does not function correctly when road pattern
stored in the map data and the actual road pattern are different due
to repair, etc.
Therefore, the map-matching function judges other road as a cur-
rently driving road if the road is not in the map, and displays the
current location mark on it. Later, the current location mark may be
repositioned to the road if the correct road is detected.
• Effective range for comparing the vehicle position and travel direc-
tion calculated by the distance and direction with the road data is
limited. Therefore, correction by map-matching is not possible
when there is an excessive gap between current vehicle position and the position on the map.
GPS (GLOBAL POSITIONING SYSTEM)
Type
Advantage
Disadvantage
Gyroscope (angular velocity
sensor)
The turning angle is precisely detected.
Errors are accumulated when driving a long dis-
tance without stopping.
GPS antenna (GPS informa-
tion)
The travel direction (North/South/East/West)
is detected.
The travel direction is not precisely detected when
driving slowly.
SEL685V
SEL686V
JSNIA0180GB