System Description

WARNING: This page is about a different car, the 2006 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.

Radio and navigation assembly outline
1. 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.
  
  Fig 1: Identifying Radio & Navigation Assembly
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Navigation system outline

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)

Fig 2: Navigation System Diagram

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OPERATION AND DESCRIPTION

Operation	Description
Vehicle Position Calculation	The radio and navigation assembly calculates the current vehicle position (direction and current position) using the direction deviation signal from the gyro sensor and the running distance signal from the vehicle speed sensor and creates the driving route.
Map Display Processing	The radio and navigation assembly displays the vehicle track on the map by processing the vehicle position data, vehicle running track, and map data from the map disc.
Map Matching	The map data from the map disc is compared to the vehicle position and running track data. Then, the vehicle position is matched with the nearest road.
GPS Correction	The vehicle position is matched to the position measured by GPS. Then, the measurement position data from the GPS unit is compared with the vehicle position and running track data. If the position is widely different, the GPS measurement position is used.
Distance	Correction The running distance signal from the vehicle speed sensor includes the error caused by tire wear and slippage between the tires and road surface. Distance correction is performed to account for this. The radio and navigation assembly automatically offsets the running distance signal to make up for the difference between the running distance signal and the distance data of the map. The offset is automatically updated.

Fig 3: Identifying GPS Radio Wave Not Reach

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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 radio wave cannot receive a signal. When only autonomous navigation is used, however, the mapping accuracy may slightly decline.

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 radio and navigation assembly.
1. Gyro sensor
  Calculates the direction by detecting angular velocity. It is located in the radio and navigation assembly.
2. Vehicle speed sensor
  Used to calculate the vehicle running distance.

GPS navigation (Satellite navigation)

This method detects the absolute vehicle position using radio waves from a GPS satellite.

* GPS satellites were launched by the U.S. Department of Defence for military purposes.

Fig 4: Identifying Radio Wave Arrival Time From Four Satellites

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

SATELLITES DESCRIPTION

Number of satellites	Measurement	Description
2 or less	Measurement impossible	Vehicle position cannot be obtained because the number of satellites is not enough.
3	2-dimensional measurement is possible	Vehicle position is obtained based on the current longitude and latitude. (This is less precise than 3-dimensional measurement.)
4	3-dimensional measurement is possible	Vehicle position is obtained based on the current longitude, latitude and altitude.

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.

Fig 5: Identifying Map Matching
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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.

Fig 6: Vehicle Position Tracking Method - Touch Switch
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DVD (Digital Versatile Disc) player outline (for navigation map)
1. The navigation ECU uses a laser pickup to read the digital signals recorded on a DVD.
  NOTE:
  - Do not disassemble any part of the navigation system.
  - Do not apply oil to the navigation system.
  - Do not insert anything but a DVD into the navigation system.
  CAUTION: Do not look directly at the laser pickup because the navigation system uses an invisible laser beam. Be sure to only operate the navigation as instructed.
CD (Compact Disc) player outline
1. 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 other things.
  NOTE:
  - 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 only operate the player as instructed.
2. Usable discs
  1. This player can only play audio CDs, CD-Rs (CD-Recordable), and CD-RWs (CD-ReWritable) that have any of the following marks:
    
    Fig 7: Identifying Player Marks
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Precautions for use of discs
  NOTE:
  - 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.
  - 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, CDR 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 also dew may form in the player. In such a case, the CD may skip or the CD may 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 road or similar uneven surface(s).
4. Cleaning
  NOTE: 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.
    
    Fig 8: Cleaning Disc Surface
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    NOTE:
    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.

MP3/WMA OUTLINE

Playable MP3 file standards

MP3/WMA OUTLINE SPECIFICATION

Compatible standard	MP3 (MPEG1 LAYER3, MPEG2 LSF LAYER 3)
Compatible sampling frequency	MPEG1 LAYER3: 32, 44.1, 48 (kHz) MPEG2 LSF LAYER3: 36, 22.05, 24 (kHz)
Compatible bit rate	MPEG1 LAYER3: 64, 80, 96, 112, 128, 160, 192, 224, 256, 320 (kbps) MPEG2 LSF LAYER3: 64, 80, 96, 112, 128, 144, 160 (kbps) Compatible with VBR
Compatible channel mode	Stereo, joint stereo, dual channel, monaural

Playable WMA file standards

FREQUENCY SPECIFICATION

Compatible standard	WMA Ver. 7, 8, and 9
Compatible sampling frequency	32, 44.1, 48 (kHz)
Compatible bit rate	Ver. 7, 8: CBR48, 64, 80, 96, 128, 160, 192 (kbps) Ver. 9: CBR48, 64, 80, 96, 128, 160, 192, 256, 320 (kbps) Compatible with playback of channel 2 only

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.
Usable media
1. Only CD-ROMs, CD-Rs (CD-Recordable), and CD-RWs (CD-ReWritable) only can be used to play MP3/WMA files
NOTE:
- 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 may not be played.
- If there are fingerprints or scratches on the disc, the disc may not be played or the CD may skip.
- Some CD-Rs and CD-RWs deteriorate if they are left in the cabin for a long time.
- Keep CD-Rs and CD-RWs in a storage case that is impenetrable to light.

Usable media format

USABLE MEDIA FORMAT

Disc format	CD-ROM Mode 1, CD-ROM XA Mode 2 Form 1
File format	ISO9660 Level 1 and Level 2 (joliet)

HINT:

As for MP3/WMA files written in any format other than those above, 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.

Standard and restrictions

STANDARD AND RESTRICTIONS

Maximum directory levels	8 levels
Maximum number of characters for a folder name/file name	16 two-byte characters (or 32 one-byte characters)
Maximum number of folders	192 (Including empty folders, route folders, and folders that do not contain MP3/WMA files)
Maximum number of files in a disc	255 (Including non-MP3/WMA files)

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".

NOTE: 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.

AVC-LAN Description
1. 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.
  
  Fig 9: AVC-LAN Communication Diagram
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Purpose:
  Recently, car audio systems have rapidly developed and the functions have vastly changed. The conventional car audio system is being integrated with multimedia 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 an audio system is equipped with a navigation system, the multi-display unit acts as the master unit. If the navigation system is not equipped, the audio head unit acts as the master unit instead. If the radio and navigation assembly is equipped, it is the master unit.
  - The radio and navigation assembly provides resistance to make communication possible.
  - 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.
Communication system outline
1. Components of the navigation system communicate with each other via the AVC-LAN.
2. The radio and navigation assembly has enough resistance (60 to 80 ) necessary for communication.
3. If a short circuit or open circuit occurs in the AVC-LAN circuit, communication is interrupted and the navigation system will stop functioning.
Diagnostic function outline
1. The audio system has a diagnostic function (the result is indicated on the master unit).
2. 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.
Bluetooth outline
1. Bluetooth is a trademark owned by Bluetooth SIG. Inc.
2. 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 multi-display (the Bluetooth system is built in), and use the hands-free function of the cellular phone, even if it is in a pocket or a 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.
  
  Fig 10: Identifying Bluetooth Trademark
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 11: Identifying Radio & Navigation Assembly
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  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.