Navigation System: Description and Operation
NAVIGATION: NAVIGATION SYSTEM: SYSTEM DIAGRAM
NAVIGATION: NAVIGATION SYSTEM: SYSTEM DESCRIPTION
1. Navigation receiver assembly outline
(a) Conventionally, 2 separate devices, a "radio and display" and a "navigation ECU" are used. This model has adopted a new type, combining these devices into a single unit.
2. Navigation system outline
(a) Vehicle position tracking methods
It is essential that the navigation system correctly tracks the current vehicle position and displays it on the map. There are 2 methods to track the current vehicle position: autonomous (dead reckoning) and GPS* (satellite) navigation. Both navigation methods are used in conjunction with each other.
*GPS (Global Positioning System)
HINT
The combination of autonomous and GPS navigation makes it possible to display the vehicle position even when the vehicle is in places where the GPS cannot receive a signal. When only autonomous navigation is used, however, the mapping accuracy may slightly decrease.
(b) Autonomous navigation
This method determines the relative vehicle position based on the running track determined by the gyro and vehicle speed sensors located in the navigation receiver assembly.
(1) Gyro sensor
Calculates the direction by detecting angular velocity. It is located in the navigation receiver assembly.
(2) Vehicle speed sensor
Used to calculate the vehicle running distance.
(c) GPS navigation (Satellite navigation)
This method detects the absolute vehicle position using radio waves from GPS satellites.
*GPS satellites were launched by the U.S. Department of Defense for military purposes.
(d) Map matching
The current driving route is calculated by autonomous navigation (according to the gyro sensor and vehicle speed sensor) and GPS navigation. This information is then compared with possible road shapes from the map data in the map disc and the vehicle position is set onto the most appropriate road.
(e) Touch switch
Touch switches are touch-sensitive (interactive) switches operated by touching the screen. When a switch is pressed, the outer glass bends in to contact the inner glass at the pressed position. By doing this, the voltage ratio is measured and the pressed position is detected.
3. DVD (Digital Versatile Disc) player outline (for navigation map)
(a) The navigation receiver assembly (built-in navigation ECU) uses a laser pickup to read the digital signals recorded on a DVD.
HINT
* Do not disassemble any part of the navigation receiver assembly (built-in navigation ECU).
* Do not apply oil to the navigation receiver assembly (built-in navigation ECU).
* Do not insert anything but a DVD into the navigation receiver assembly (built-in navigation ECU).
CAUTION:
Do not look directly at the laser pickup because the navigation receiver assembly (built-in navigation ECU) uses an invisible laser beam.
Be sure to operate the navigation system only as instructed.
4. CD (Compact Disc) player outline
(a) A compact disc player uses a laser pickup to read digital signals recorded on a compact disc (CD). By converting the digital signals to analog, it can play music and audio.
NOTICE:
* Do not disassemble any part of the CD player.
* Do not apply oil to the CD player.
* Do not insert anything but a CD into the CD player.
CAUTION:
Do not look directly at the laser pickup because the CD player uses an invisible laser beam. Be sure to operate the player only as instructed.
(b) Usable discs
(1) This player can play only audio CDs, CD-Rs (CD-Recordable), and CD-RWs (CD-ReWritable) that have any of the following marks:
(c) Precautions for use of discs
NOTICE:
* Copy-protected CDs cannot be played.
* CD-Rs and CD-RWs may not be played depending on the recording conditions or characteristics of the discs, or due to damage, dirt, or deterioration caused by leaving the discs in the cabin for a long time.
* Unfinalized CD-Rs and CD-RWs cannot be played.
* Dual Discs that mate DVD recorded material on one side with CD digital audio material on the other cannot be played.
* Keep the discs away from dirt. Be careful not to damage the discs or leave your fingerprints on them.
* Hold discs by the outer edge and center hole with the label side up.
* Leaving the disc exposed halfway out of the slot for a long time after pressing the disc eject button may cause deformation of the disc, making the disc unusable.
* If discs have adhesive tape, stickers, CD labels, or any traces of such labels attached, the discs may not be ejected or player malfunctions may result.
* Keep the discs away from direct sunlight. (Exposure to direct sunlight may cause deformation of the disc, making the disc unusable.)
* Do not use odd-shaped CDs because these may cause player malfunctions.
* Do not use discs whose recording portion is transparent or translucent because they may not be inserted, ejected, or played normally.
HINT
* When it is cold or it is raining, if the windows mist up, mist and condensation may form in the player. In such cases, the CD may skip or stop in the middle of play. Ventilate or dehumidify the cabin for a while before using the player.
* The CD may skip if the player experiences strong vibrations when the vehicle is driven on rough roads or similar uneven surface(s).
(d) Cleaning
NOTICE:
Do not use a lens cleaner because it may cause a malfunction in the pickup portion of the player.
(1) If dirt is on the disc surface, wipe it clean with a soft dry cloth such as an eyeglass cleaner for plastic lenses from the inside to the outside in a radial direction.
NOTICE:
* Pressing on the disc by hand or rubbing the disc with a hard cloth may scratch the disc surface.
* Use of solvent such as a record spray, antistatic agent, alcohol, benzine, and thinner, or a chemical cloth may cause damage to the disc, making the disc unusable.
5. MP3/WMA OUTLINE
(a) Playable MP3 file standards
(b) Playable WMA file standards
(c) ID3 tag and WMA tag
(1) Additional textual information called ID3 tag can be input to MP3 files. Information such as song titles and artist names can be stored.
HINT
This player is compatible with the ID3 tags of ID3 Ver. 1.0 and 1.1, and ID3 Ver. 2.2 and 2.3. (Number of characters complies with ID3 Ver. 1.0 and 1.1.)
(2) Additional textual information called WMA tag can be input to WMA files. Information such as song titles and artist names can be stored.
(d) Usable media
(1) Only CD-ROMs, CD-Rs (CD-Recordable), and CD-RWs (CD-ReWritable) can be used to play MP3/WMA files.
NOTICE:
* CD-Rs and CD-RWs are more easily affected by a hot and humid environment than discs used for normal audio CDs. For this reason, some CD-Rs and CD-RWs do not play.
* If there are fingerprints or scratches on the disc, the disc may not play or the CD may skip.
* Some CD-Rs and CD-RWs may deteriorate if they are left in the cabin for a long time.
* Keep CD-Rs and CD-RWs in an opaque case.
(e) Usable media format
(1) Usable media format
HINT
* As for MP3/WMA files written in any unlisted format, the contents of the files may not be played normally or the file names or folder names may not be displayed correctly.
* This player is compatible with multi-session discs and can play CD-Rs and CD-RWs on which MP3/WMA files are added. However, only the first session can be played.
* Discs whose first session includes both music data and MP3 or WMA format data cannot be played.
(2) Standard and restrictions
(f) File names
(1) Only files with an extension of ".mp3" or ".wma" can be recognized and played as MP3 or WMA files.
(2) Save MP3 or WMA files with an extension of ".mp3" or ".wma".
NOTICE:
If saving non-MP3 or non-WMA files with an extension of ".mp3" or ".wma", those files are wrongly recognized as MP3 or WMA files and played. A loud noise may occur and damage to the speaker may result.
6. AVC-LAN Description
(a) What is AVC-LAN?
AVC-LAN, an abbreviation for "Audio Visual Communication Local Area Network", is a united standard developed by the manufacturers in affiliation with Toyota Motor Corporation. This standard pertains to audio and visual signals as well as switch and communication signals.
(b) Purpose:
Recently, car audio systems have rapidly developed and the functions have vastly changed. The conventional car audio system is being integrated with multi-media interfaces similar to those in navigation systems. At the same time, customers are demanding higher quality from their audio systems. This is merely an overview of the standardization background. The specific purposes are as follows:
(1) To solve sound problems, etc. caused by using components of different manufacturers through signal standardization.
(2) To allow each manufacturer to concentrate on developing products they do best. From this, reasonably priced products can be produced.
HINT
* If a short to +B or short to ground is detected in the AVC-LAN circuit, communication is interrupted and the audio system will stop functioning.
* If the audio system has a navigation system installed, the multi-display unit acts as the master unit.
* If the navigation system is not installed, the audio head unit acts as the master unit instead. If the navigation receiver assembly is installed, it is the master unit.
* The navigation receiver assembly contains a resistor that is necessary to enable communication on the different AVC-LAN circuits.
* The car audio system with an AVC-LAN circuit has a diagnostic function.
* Each component has a specified number (3-digit) called a physical address. Each function has a number (2-digit) called a logical address.
7. Communication system outline
(a) Components of the navigation system communicate with each other via the AVC-LAN.
(b) The navigation receiver assembly has enough resistance (60 to 80 Ohms) necessary for communication.
(c) If a short circuit or open circuit occurs in the AVC-LAN circuit, communication is interrupted and the navigation system will stop functioning.
8. Diagnostic function outline
(a) The audio system has a diagnostic function (the result is indicated on the master unit).
(b) A 3-digit hexadecimal component code (physical address) is allocated to each component on the AVC-LAN. Using this code, the component in the diagnostic function can be displayed.
9. "Bluetooth" outline
(a) "Bluetooth" is a trademark owned by Bluetooth SIG. Inc.
(b) "Bluetooth" is a new wireless connection technology that uses the 2.4 GHz frequency band. This makes it possible to connect a cellular phone ("Bluetooth" compatible phone*1) to the navigation receiver assembly (the "Bluetooth" system is built-in), and use the handsfree function of the cellular phone, even if it is in a pocket or bag. As a result, it is not necessary to use a connector attached directly to the cellular phone.
*1: Some versions of "Bluetooth" compatible cellular phones may not function.
HINT
The communication performance of "Bluetooth" may vary depending on obstructions or radio wave conditions between communication devices, electromagnetic radiation, communication device sensitivity, or antenna capacity.
10. ASL (Automatic Sound Levelizer) function outline
(a) The ASL (Automatic Sound Levelizer) function automatically adjusts the sound volume in order to enable clear audio quality even when vehicle noise increases (as vehicle noise increases, the volume is turned up etc.).
Vehicle speed signals are received from the combination meter and used for the ASL (Automatic Sound Levelizer).