NOTE:
The road map data is based on data stored in the map DVD-ROM.
SEL686V
I
In map-matching, alternative routes to reach the destination
will be shown and prioritized, after the road on which the
vehicle is currently driven has been judged and the current-lo-
cation mark has been repositioned.
If there is an error in distance and/or direction, the alternative
routes will be shown in different order of priority, and the wrong
road can be avoided.
If two roads are running in parallel, they are of the same pri-
ority. Therefore, the current-location mark may appear on
either of them alternately, depending on maneuvering of the
steering wheel and configuration of the road.
SKIA0613E
I
Map-matching does not function correctly when the road on
which the vehicle is driving is new and not recorded in the map
DVD-ROM, or when the road pattern stored in the map data
and the actual road pattern are different due to repair.
When driving on a road not present in the map, the map-
matching function may find another road and position the cur-
rent-location mark on it. Then, when the correct road is
detected, the current-location mark may leap to it.
I
Effective range for comparing the vehicle position and travel
direction calculated by the distance and direction with the road
data read from the map DVD-ROM is limited. Therefore, when
there is an excessive gap between the current vehicle position
and the position on the map, correction by map-matching is not
possible.
SEL526V
GPS (GLOBAL POSITIONING SYSTEM)
NLEL0593S04
GPS (Global Positioning System) has been developed and con-
trolled by the US Department of Defense. The system utilizes GPS
satellite (NAVSTAR), sending out radio waves while flying on an
orbit around the earth at the height of approx. 21,000 km (13,000
miles).
The GPS receiver calculates the vehicle’s position in three dimen-
sions (latitude/longitude/altitude) according to the time lag of the
radio waves received from four or more GPS satellites (three-di-
mensional positioning). If radio waves were received only from
three GPS satellites, the GPS receiver calculates the vehicle’s
position in two dimensions (latitude/longitude), utilizing the altitude
NAVIGATION SYSTEM
System Description (Cont’d)
EL-376