GF82.61-P-4111FAB Radio/Navigation Unit, Component Description
GF82.61-P-4111FAB Radio/Navigation Unit, Component Description
MODEL 203.7
- with CODE (525) MB Audio 50 APS radio
MODEL 203.7 as of model year 09/Modification Year 08 model refinement package
A2/56 Radio and navigation unit
Location
The radio and navigation unit is located in the center console.
Task
The radio and navigation unit is used for central control of the following systems:
- Audio:
- Radio operation with integrated radio tuner
- Audio CD operation with integrated CD drive
- Integrated basic audio amplifier
- Amplifier for sound system (N40/3), with code (810) Sound system
- CD player with changer (in glove compartment) (A2/6) with code (819) 6-disk CD changer
- AUX jack in glove compartment
- Navigation: With integrated Global Positioning System (GPS) receiver, turn rate sensor, navigation processor and CD drive
- Telephone, with code (386) Mobile phone:
- Universal Portable Cell Phone Interface (UPCI [UHI]) control unit (N123/1)
- Voice control, with code (813) Voice control system (VCS [SBS]):
- Voice control system control unit (A35/11)
- Interface between Media Oriented System Transport (MOST) and interior CAN
- Diagnosis gateway for all MOST components
The radio and navigation unit reads in the following signals over direct lines:
- Circuit 30
- Circuit 31
- Wake-up
- AUX jack
- GPS antenna (A2/49a2)
- Window antenna amplifier module 2 (A2/72)
The radio and navigation unit processes the signals and sends the following output signals over direct lines:
- Signals for speakers, except code (810) Sound system
- Switching voltage for antennas
The radio and navigation unit receives, processes and sends signals over the following data buses:
- Interior CAN
- MOST
Design
- Operating unit
- Color display
- CD drive (audio, navigation)
- GPS receiver
- Turn rate sensor
- Navigation processor
- Control electronics
- Basic audio amplifier
- External additional fan
Function
A distinction is made between the following functional areas:
- Operating elements
- Graphic editing and image output
- Audio signal output
- Info menu
- Diagnostic interface and error management
- Navigation processor and GPS receiver
- Yaw rate sensor
- CD drive
- Traffic data recorder
Operating elements
The control buttons and switches of the function keypad on the radio and navigation unit are read in by the microcontroller and transmitted to the central computer. The button inputs are processed in the central computer or sent over the MOST or interior CAN in the form of a data telegram.
Graphic editing and image output
The video subsystem takes over editing and output of the control displays. The operating screens are put out internally by the video subsystem via the composite video (FBAS) signal input to the display.
The information and amplitudes of the 3 basic colors red, green and blue as well as a synchronization signal are included in the composite color video signal. The control electronics in the display unit evaluates the composite color video signal and controls the individual pixels line by line in terms of color and intensity.
There is a pulse at the end of each line which synchronizes the horizontal video signal. The electronic circuitry of the display unit then starts the next line. Once the last line is reached on the display, a pulse is sent, which synchronizes the vertical picture signal. The electronics then actuate the 1st line again.
Audio signal output
The audio signals of the various sources (CD, voice output for destination-oriented navigation, etc.) are processed by the radio and navigation unit, and amplified before being emitted via the vehicle speakers. If the vehicle is equipped with code (810) Sound system, the final amplification of the audio signals is carried out by the amplifier for sound system (N40/3). For this purpose, the audio source data is transmitted over MOST digitally to the amplifier for sound system.
Info menu
Using the "i" or "INF keys" takes you straight to the information menu. This usability can be selected independent of the source (e.g. from telephone or radio menu). A return is made to the screen from which the info was selected, by means of the Back key. If Mode point has been selected in the Info menu, then when the Back key is pressed one jumps back to the screen that preceded the Info menu.
Diagnostic interface and error management
While the radio and navigation unit is active, the system saves all errors in a nonvolatile memory. These can be read out via the data link connector (X11/4) using STAR DIAGNOSIS. It is not possible to output faults via the display. The diagnosis also encompasses the components connected to MOST, that all have their own fault memory. Faults are sent when requested by Star Diagnosis over MOST to the radio and navigation unit, where they can then be read out.
Navigation processor and GPS receiver
The navigation processor is the central component of the navigation system. It is integrated into the radio and navigation unit and calculates the location of the vehicle using the incoming signals; it also calculates the vehicle's route after the destination has been entered. The GPS receiver is a part of the navigation processor. It evaluates the satellite signals coming from the GPS antenna and uses them to calculate the vehicle position.
Gyro sensor
The turn rate sensor determines vehicle direction changes. It is installed into the navigation processor. A calibration is not required.
CD drive
With the aid of the integrated standard CD drive, data can be read from the special navigation CDs or audio CDs can be played. Software updates for the radio and navigation unit are also installed using the CD drive.
The following data are located on the navigation CD:
- Program data for execution in the navigation processor
- Voice data for voice output
- Map data
The traffic data memory
The integrated traffic data recorder receives traffic information either over the MOST or internally from the radio tuner. The data are stored for a maximum of 30 minutes in the traffic data recorder (up to 100 messages), including during the run-on time of the radio and navigation unit.
The traffic data memory decodes the messages and transmits them to the navigation processor as required. For synchronization, the traffic data recorder requires a current location list from the navigation processor. The monitoring points required for checking the road network (e.g. highway exit) are defined in this list by unique numbers. The list of locations is stored on the navigation CD. It is automatically loaded (e.g. if CD is changed) from the navigation processor into the traffic data recorder.
