NAVIGATION SYSTEM
AV-57
C
D
E
F
G
H
I
J
L
MA
B
AV
Revision: 2006 November2007 350Z
NAVIGATION SYSTEMPFP:25915
System DescriptionNKS000CX
For Navigation System operation information, refer to Navigation System Owner's Manual.
LOCATION DETECTION PRINCIPLE
The navigation system periodically calculates the vehicle's current
position according to the following three signals:
Travel distance of the vehicle as determined by the vehicle
speed sensor
Turning angle of the vehicle as determined by the gyroscope
(angular velocity sensor)
Direction of vehicle travel as determined by the GPS antenna
(GPS information)
The current position of the vehicle is then identified by comparing the
calculated vehicle position with map data read from the DVD-ROM,
which is stored in the DVD-ROM drive (map-matching), and indi-
cated on the screen as a current-location mark. More accurate data is judged and used by comparing vehicle
position detection results found by the GPS with the result by map-matching.
The current vehicle position will be calculated by detecting the dis-
tance the vehicle moved from the previous calculation point and its
direction.
Travel distance
Travel distance calculations are based on the vehicle speed
sensor input signal. Therefore, the calculation may become
incorrect as the tires wear down. To prevent this, an automatic
distance correction function has been adopted.
Travel direction
Change in the travel direction of the vehicle is calculated by a
gyroscope (angular velocity sensor) and a GPS antenna (GPS
information). They have both advantages and disadvantages.
More accurate traveling direction is detected because priorities are set for the signals from these two
devices according to the situation.
SKIB1058E
SEL684V
Type Advantage Disadvantage
Gyroscope (angular velocity sen-
sor)Can detect the vehicle's turning angle quite
accurately.Direction errors may accumulate when vehicle is
driven for long distances without stopping.
GPS antenna (GPS information)Can detect the vehicle's travel direction
(North/South/East/West).Correct direction cannot be detected when vehi-
cle speed is low.
