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Nissan Titan A60. Manual - part 93

NAVIGATION SYSTEM

AV-197

< SYSTEM DESCRIPTION >

[PREMIUM WITH NAVIGATION]

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

NAVIGATION SYSTEM

AV-199

< SYSTEM DESCRIPTION >

[PREMIUM WITH NAVIGATION]

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

Front tweeter LH M109

Steering wheel audio control switch-
es

Center speaker M110

Display unit M93

Display control unit M94, M95

Front tweeter RH M111

AV switch M98

Audio unit M42, M43, M44, M45, M46 9.

Aux jack M104

AWNIA2290ZZ

Content .. 91 92 93 94 ..