System Diagram
System Description
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 data, which is stored in the hard disk drive (HDD) (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 distance 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
Type |
Advantage |
Disadvantage |
Gyroscope (angular velocity sensor) |
|
|
GPS antenna (GPS information) |
|
|
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 data stored on the HDD.
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.
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.
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 currentlocation mark may leap to it.
GPS (GLOBAL POSITIONING SYSTEM)
GPS (Global Positioning System) has been developed and controlled 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 mi).
The GPS receiver calculates the vehicle's position in three dimensions (latitude/longitude/altitude) according to the time lag of the radio waves received from four or more GPS satellites (three-dimensional 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 calculated previously by using radio waves from four or more GPS satellites (two-dimensional positioning).
Accuracy of the GPS will deteriorate under the following conditions.
Component Parts Location
Component Description
Part name |
Description |
AV control unit |
|
BOSE speaker amp | Voice guidance signal is input from AV control unit, and it is output to speakers. |
Tweeter | Voice guidance signal from BOSE speaker amp. is output |
Steering wheel audio control switches |
|
Microphone | Sends voice signals to AV control unit |
GPS antenna | GPS signal is received and is output to AV control unit. |
Precaution
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and
"SEAT BELT PRE-TENSIONER"
The Supplemental Restraint System such as "AIR BAG" and "SEAT BELT
PRE-TENSIONER", used along with a front seat belt, helps to reduce the risk
or severity of injury to the driver and front passenger for ...
Cleaning interior
Occasionally remove loose dust from the interior
trim, plastic parts and seats using a vacuum
cleaner or soft bristled brush. Wipe the vinyl and
leather (if so equipped) surfaces with a clean,
soft cloth dampened in mild soap solution, then
wipe clean with a dry, soft cloth.
Regular care and ...
Headlamp
System Diagram
System Description
Control of the headlamp system operation is dependent upon the position of
the combination switch (lighting and turn signal switch). When the lighting
switch is placed in the 2nd position, the BCM (body control module) receives
input requesting the headlam ...