Navigation, function

P82.61-4162-79

Function requirements for SD (Secure Digital) map navigation, general

 Circuit 30g ON

 Transport mode not active

 Authorized SD card for CODE 357 (SD card navigation) in SD card drive

 Signals from at least 4 Global Positioning System (GPS) satellites are present.

 Radio is switched on.

 The SD card is authorized for the respective radio and can then no longer be used for another radio.

SD (Secure Digital) map navigation, general

With SD card navigation, the radio is supported by the following vehicle components:

 Map data from SD card

 GPS signals from the multifunction antenna, with CODE 348 (Emergency call/assist system) via the global positioning system antenna splitter

 2-D gyro sensor signals from the gyro sensor integrated in the radio

 Wheel speed signals over the CAN from Electronic Stability Program control unit (except model 212.095/195/098/298 and except CODE 233 (DISTRONIC PLUS)), from the regenerative braking system control unit (model 212.095/195/098/298) or from the Premium Electronic Stability Program control unit (with CODE 233 (DISTRONIC PLUS))

 Reverse gear signal via the interior CAN from the front SAM control unit with fuse and relay module

 Operation via the left multifunction steering wheel button group and the right multifunction steering wheel button group

 Operation via the Audio/COMAND control panel

 Operation via the hands-free system microphone

 Audio output via the front vehicle speakers, including audio fadeout, with CODE 810 (Sound system) regulated by sound system amplifier control unit

 Image output and map display on the Audio/COMAND display, additionally in the instrument cluster; the view and the menu display are generated by the radio using the SD map data available

 Traffic Message Channel (TMC) or comparable radio traffic messages via the FM radio tuner integrated into the radio

 Real Time Traffic Data (RTTD) over MOST from the tuner unit (with CODE 536 (SIRIUS satellite radio))

 Updates of map data and navigation software via SD card to Internet-capable PC

Function sequence for SD card navigation

The radio accesses the map data stored on the SD card.

 When the SD card is used for the first time in the vehicle, data is written to a configuration file on the SD card by the radio.

The GPS signals are received by the radio via a direct line from the multifunction antenna; in vehicles with CODE 348 (Emergency call/assist system), via the global positioning system antenna splitter.

 Since GPS operates in the gigahertz range (microwaves) and the signals are weak, the following events may lead to reception interference: Atmospheric interferences (e.g. bad weather, water vapor, fog), multi-path reception due to reflections of the signals (e.g. at building walls) or signal shadowing (e.g. in built-up areas, in tunnels, due to tall buildings or trees).

In the event of a failure of the GPS signals, the radio reverts back to the basic position finding. For basic position finding, the radio evaluates the data of the integrated 2-D gyro sensor as well as the wheel speed signals and the reverse gear signal.

The wheel speed signals are sent to the radio by the Electronic Stability Program control unit (except model 212.095/195/098/298 and except CODE 233 (DISTRONIC PLUS)), by the regenerative braking system control unit (model 212.095/195/098/298) or the Premium Electronic Stability Program control unit (with CODE 233 (DISTRONIC PLUS)) via the following route:

 Chassis CAN 1

 Front SAM control unit with fuse and relay module

 Interior CAN

The reverse gear signal is received by the radio over the interior CAN by the front SAM control unit with fuse and relay module.

 Location errors in position finding, rolling backwards with "circuit 15 OFF" (ignition switched off) or transport of the vehicle falsify the basic position finding. In both instances, the deviation is automatically corrected by the navigation processor integrated into the radio when it receives GPS data.

The control signals from the left multifunction steering wheel button group and the right multifunction steering wheel button group are transferred to the radio as follows:

 Steering wheel electronics

 Steering LIN

 Steering column module control unit

 Chassis CAN 1

 Front SAM control unit with fuse and relay module

 Chassis CAN 2

 Instrument cluster

 Interior CAN

The control signals of the Audio/COMAND control panel are transmitted to the radio via telematics CAN. The radio receives the voice inputs through the hands-free system microphone via a direct line. The voice output is forwarded by the radio in vehicles except CODE 810 (Sound system) to the speaker system. In vehicles with CODE 810 (Sound system), the radio sends the voice output via MOST to the sound system amplifier control unit. The sound system amplifier control unit amplifies the signals and forwards them to the speaker system.

 More detailed information on the speaker system is available in the "Speaker output function" document.

The radio switches on the Audio/COMAND display via telematics CAN. The radio transmits the picture signals to the Audio/COMAND display via an LVDS line (Low Voltage Differential Signal). The traffic messages from the integrated FM radio tuners are transferred within the radio.

On vehicles with CODE 536 (SIRIUS satellite radio) the tuner unit receives real-time traffic data (RTTD) over a direct line from the multifunction antenna, and sends it to the radio's navigation system over MOST.

 The real-time traffic data (RTTD) includes accident and traffic jam messages as well as traffic flow information. The real-time traffic data is available around the major cities in the USA, and is transmitted every 5 minutes.

 Updates on the SD card takes are downloaded externally on an Internet-capable PC; this is described in the operator's manual.