Nissan Titan A60. Manual — part 93
AV
NAVIGATION SYSTEM
AV-197
< SYSTEM DESCRIPTION >
[PREMIUM WITH NAVIGATION]
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NAVIGATION SYSTEM
System Diagram
INFOID:0000000006166557
System Description
INFOID:0000000006166558
NOTE:
Refer to NAVI System Owner's Manual for system operation.
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), and the 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 map DVD-ROM, which is stored in the DVD-ROM drive (map-matching), and indicated on the
screen with a current-location mark.
By comparing the vehicle position detection results found by the
GPS and by map-matching, more accurate vehicle position data can
be used.
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 input signal. Therefore, the calculation may
become incorrect as the tires wear down. To prevent this, an automatic distance fine adjustment 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). As the gyroscope and GPS antenna have both merit and demerit, input signals
from them 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.
AWNIA1625GB
SEL684V
AV-198
< SYSTEM DESCRIPTION >
[PREMIUM WITH NAVIGATION]
NAVIGATION SYSTEM
MAP–MATCHING
Map–matching is a function that repositions the vehicle on the road
map when a new location is judged to be the most accurate. This is
done by comparing the current vehicle position, calculated by the
method described in the position detection principle, with the road
map data around the vehicle, read from the map DVD-ROM stored
on the DVD-ROM drive.
Therefore, the vehicle position may not be corrected after the vehicle
is driven over a certain distance or time in which GPS information is
hard to receive. In this case, the current-location mark on the display
must be corrected manually.
CAUTION:
The road map data is based on data stored on the HDD.
• In map-matching, alternative routes to reach the destination will be
shown and prioritized, after the road on which the vehicle is cur-
rently driven has been judged and the current-location 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 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.
• Map-matching does not function correctly when the road on which
the vehicle is driving is new and not recorded in the 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 current-location
mark on it. Then, when the correct road is detected, the current-
location mark may leap to it.
• Effective range for comparing the vehicle position and travel direc-
tion calculated by the distance and direction with the road data
read from the DVD-ROM is limited. Therefore, when there is an
excessive gap between the current vehicle position and the posi-
tion on the map, correction by map-matching is not possible.
GPS (GLOBAL POSITIONING SYSTEM)
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-dimen-
sional 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 data calcu-
lated previously by using radio waves from four or more GPS satel-
lites (two-dimensional positioning).
Type
Advantage
Disadvantage
Gyroscope (angular velocity sensor)
• Can detect the vehicle's turning angle quite
accurately.
• Direction errors may accumulate when the ve-
hicle is driven for long distances without stop-
ping.
GPS antenna (GPS information)
• Can detect the vehicle's travel direction
(North/South/East/West).
• Correct direction cannot be detected when the
vehicle speed is low.
SEL685V
SEL686V
SKIA0613E
SEL526V
AV
NAVIGATION SYSTEM
AV-199
< SYSTEM DESCRIPTION >
[PREMIUM WITH NAVIGATION]
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Accuracy of the GPS will deteriorate under the following conditions.
• In two-dimensional positioning, the GPS accuracy will deteriorate when the altitude of the vehicle position
changes.
• There may be an error of approximately 10 m (30 ft.) in position detected by three-dimensional positioning,
which is more accurate than two-dimensional positioning. The accuracy can be even lower depending on the
arrangement of the GPS satellites utilized for the positioning.
• Position detection is not possible when the vehicle is in an area where radio waves from the GPS satellite do
not reach, such as in a tunnel, parking lot in a building, and under an elevated highway. Radio waves from
the GPS satellites may not be received when some object is located over the GPS antenna.
• Position correction by GPS is not available while the vehicle is stopped.
COMPONENT DESCRIPTION
NAVI Control Unit
• The gyro (angular speed sensor) and the DVD-ROM drive are
built-in units that control the navigation functions.
• Signals are received from the gyro, the vehicle speed sensor, and
the GPS antenna. Vehicle location is determined by combining this
data with the data contained in the DVD-ROM map. Location infor-
mation is shown on liquid crystal display (display unit).
• Maps, traffic control regulations, and other pertinent information
can be easily read from the DVD-ROM disc.
• The oscillator gyro sensor is used to detect changes in vehicle
steering angle.
Map DVD-ROM
• The map DVD-ROM has maps, traffic control regulations, and other pertinent information.
• To improve DVD-ROM map matching and route determination functions, the DVD-ROM uses an exclusive
Nissan format. Therefore, the use of a DVD-ROM provided by other manufacturers cannot be used.
Display Control Unit
The display control unit coordinates audio and video signals between the NAVI control unit and the display
unit.
Display Unit
Displays NAVI system information.
AV Switch
AV switch allows user to input NAVI display settings. Self diagnostics are initiated using AV switch.
GPS Antenna
GPS antenna sends signals to NAVI control unit.
WKIA4593E
AV-200
< SYSTEM DESCRIPTION >
[PREMIUM WITH NAVIGATION]
NAVIGATION SYSTEM
Component Parts Location
INFOID:0000000006706844
:FRONT
1.
Front tweeter LH M109
2.
Steering wheel audio control switch-
es
3.
Center speaker M110
4.
Display unit M93
5.
Display control unit M94, M95
6.
Front tweeter RH M111
7.
AV switch M98
8.
Audio unit M42, M43, M44, M45, M46 9.
Aux jack M104
AWNIA2290ZZ
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