System Description

SYSTEM DESCRIPTION

System Functions
Here is an example of functions. For details, refer to the owner's manual or navigation system owner's manual.

AUDIO

AudioPilot(r) (for BOSE System)
AudioPilot(r) is the sound improving system that picks up any noises and the sound of music coming into the vehicle by a microphone under the steering, and that the BOSE amp revises the frequency feature of music at real time in response to the frequency feature of the noise while driving and listening to music.
- If low frequency area noise from vehicle is loud, it adjusts low frequency element of music to be bigger than vehicle noise.
- If high frequency area noise from vehicle is loud, it adjusts all frequency element of music to be bigger than vehicle noise.

Centerpoint(r) (for BOSE Surround 5.1ch System)
CD and 2.0ch DVD stereo sound played at audio unit and DVD player are subjected to signal processing in BOSE amp. It can play the surround sound with presence.

VEHICLE INFORMATION SYSTEM
- The status of audio, climate control system, fuel consumption, and navigation system (if equipped) are displayed.
- AV (NAVI) control unit receives the data signal from ECM, unified meter and A/C amp and low tire pressure warning control unit via CAN communication. It calculates the values of fuel economy, tire pressure, and trip computer from the received information and displays them.

NAVIGATION SYSTEM

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 map DVD-ROM, which is stored in the DVD-ROM drive (map-matching), and indicated on the screen as a vehicle 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 distance 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.




Map-Matching
Map-matching compares a current location detected by the method in the "Location Detection Principle" with a road map data from Map DVD-ROM stored in DVD-ROM drive.

NOTE: The road map data is based on data stored in the map DVD-ROM.

The vehicle position may not be corrected under the following circumstances and after driving for a certain time when GPS information is difficult to receive. In this case, the vehicle mark on the display must be corrected manually.




- 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 vehicle mark has been repositioned.

If there is an error in distance and/or direction, alternative routes will be shown in different order of priority, and the incorrect road can be avoided.

If two roads are running in parallel, they are of the same priority. Therefore, the vehicle 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 a road on which the vehicle is driving is new and not recorded in the map DVD-ROM, or when 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 vehicle mark on it. Then, when the correct road is detected, the vehicle mark may change to it.

- 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 current vehicle position and the position on the map, correction by map-matching is not possible.

GPS (Global Positioning System)




GPS (Global Positioning System) was developed for and is controlled by the US Department of Defense. The system utilizes GPS satellites (NAV-STAR), sending out radio waves while flying on an orbit around the earth at an altitude of approximately 21,000 km (13,100miles).

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 with radio waves from four or more GPS satellites (two-dimensional positioning).

Position correction by GPS is not available while the vehicle is stopped.
Accuracy of GPS will deteriorate under the following conditions:
- In two-dimensional positioning, GPS accuracy will deteriorate when altitude of the vehicle position changes.
- The accuracy can be even lower depending on the arrangement of the GPS satellites utilized for the positioning.
- Position detection is not possible when 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.

NOTE:
- Even a high-precision three dimensional positioning, the detection result has an error about 10 m (30ft).
- Because the signals of GPS satellite is controlled by the Tracking and Control Center in the United States, the accuracy may be degraded lower intentionally or the radio waves may stop.

MOBILE ENTERTAINMENT SYSTEM
- The wireless headphone has been adopted to the rear seat. It is possible to listen to a separate sound in front seat and rear seat and to see a separate image in front display and rear display.
- When headphone mode is turned ON at radio/CD changer mode, AUX or DVD mode is turned ON only for rear seat. The image that is different from front seat is displayed and a separate sound is output from speaker and headphone.

HANDS-FREE PHONE
- AV (NAVI) control unit has a Bluetooth module. It can perform wireless hands-free telephone calls using the portable phone in a pocket.
- 5 or more portable phones can be registered into the AV (NAVI) control unit.

REAR VIEW MONITOR
- The small CCD camera is equipped into the rear end of the vehicle. The rear view monitor that displays the area behind the vehicle while backing up is equipped.
- Guiding lines indicating side and rear clearances are provided in the rear view monitor image, which allows the driver to more easily judge distances between the vehicle and objects in the display. The possible route lines that indicate the possible route according to the steering angle are provided to help backing up when parking.
- Image quality of the rear view image and of the navigation screen can be adjusted separately.