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Home >> Mercedes Benz >> 2020 >> SLC43 AMG Base >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System - Body - 172 Chassis - 2 Of 5 >> Basic Knowledge >> Navigation Mode, Function >> Navigation Mode, Function - GF82.85-P-2012RD

Navigation Mode, Function - GF82.85-P-2012RD

Model 172.4 

up to model year 2017 

with code 512 (COMAND APS with DVD changer) 

Model 172.4 

up to model year 2017 

with code 527 (COMAND APS with single DVD drive (with navigation)) 

G13848176Courtesy of MERCEDES-BENZ USA

Shown on model 172.4 

Function requirements for navigation mode in general 

General navigation mode 

The navigation module is integrated in the COMAND controller unit.

The navigation system includes the following functionalities:

After entering the destination, the location of the vehicle and the direction and distance to the destination are determined with the aid of the navigation system.

After entering or selecting a destination location, route calculation starts. A range of options can be selected for route calculation according to the national version, e.g. :

If observance of the options is not possible, then the options set are ignored for the sections in question and a message is displayed and signaled audibly. The set options can be displayed and changed at any time. Once calculated, the route is displayed using arrow pictograms on the Audio/COMAND display and this information is also issued as an acoustic notification: "The route is being calculated".

If the vehicle deviates from the route, the new route is re-calculated. If the recalculated values are plausible for the navigation system, then the modified route is displayed.

IMPORTANT Dynamic route guidance (for "Dynamic route" or "Eco route"): Dynamic route guidance offers an alternative route if the calculated route has a traffic jam or a roadblock on it.

The navigation system also has lists and card data for points of interest (e.g. restaurants, filling stations, parking lots, shopping centers), which can be selected as the destination or for a stopover. Destinations (for vehicles except code 498 (Japan version) including complete routes) can be sent over the Internet using the Mercedes-Benz Application Gateway to the vehicle and transferred into the navigation system. For vehicles with code 348 (Emergency call/Assist system) or with code 359 (TELEAID emergency call system) the Service Center can provide destination entries or POIs to the COMAND controller unit's navigation module.

The navigation system can be operated with the following components:

When entered using the Audio/COMAND control panel, the control signals are transmitted via the telematics CAN to the COMAND controller unit.

When entries are made via the control panels on the COMAND controller unit, the control signals are processed within the unit.

The steering wheel electronics sends the control signals from the left and right multifunction steering wheel button groups as follows:

Steering LIN →

Steering column tube module control unit →

Chassis CAN →

Instrument cluster →

Interior CAN →

COMAND control unit

When operating with the voice control system, voice input takes place via the inside rearview mirror microphone.

Words spoken into the inside rear-view mirror microphone are converted into an electrical signal and forwarded via a direct line to the COMAND controller unit.

IMPORTANT For navigation operation using the voice control system, additional lists of names are made available. There are additional name lists, e.g. for the following information: Place names for selected towns/cities on the data medium, street names for all towns, town centers.

The navigation function consists of the following subfunctions:

General information on GPS position finding 

The GPS is a satellite-based positioning system, which is available on a global basis. GPS position finding is irretrievable after vehicle transport (e.g. by train or ferry or after towing). Recalculating the GPS position (after satellite reception has been interrupted) can take several minutes (up to 5 minutes during initial commissioning). The accuracy of the position finding and the actual calculation are essentially based on the measurement of the run times of the signals sent synchronously by the various satellites. A vital precondition is the synchronicity of the clocks in the satellites and in the receiver. To ensure synchronicity, the receiver is equipped with an automatic time correction that is possible thanks to the satellite signals.

GPS position finding function sequence 

The GPS receiver of the COMAND controller unit receives the GPS signals - depending on equipment installed - either from the GPS antenna or from the multifunction antenna. In vehicles with code 348 (Emergency call/Assist system) or with code 359 (TELEAID emergency call system), the signals are received by the multifunction antenna over the Global Positioning System antenna splitter.

The GPS signals are used by the COMAND controller unit to calculate the current vehicle position (receiver). The direction of travel is determined with the aid of the sequence of locations calculated with the GPS system.

IMPORTANT Because 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), signal shadowing (e.g. in built-up areas, in tunnels, due to tall buildings or trees).

General information on basic position finding 

Navigation can be continued without a GPS signal using basic position finding. A defect, e.g. in the multifunction antenna or the GPS antenna may therefore not be immediately noticeable.

Basic position finding runs parallel to GPS position finding. For basic position finding the COMAND controller unit requires the following information:

Basic position finding function sequence 

For basic position finding, the COMAND controller unit requires signals from the following components:

The data from the gyro sensor integrated in the COMAND controller unit is forwarded within the COMAND controller unit.

The Electronic Stability Program control unit sends the data over the following path:

Chassis CAN →

Front SAM control unit →

Interior CAN →

COMAND control unit

The signals received are used by the COMAND controller unit to calculate the current position of the vehicle (degrees of longitude and latitude). The basic position finding calculation is performed approx. once per second.

IMPORTANT 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 COMAND controller unit's integrated navigation processor upon reception of GPS data.

Calibration 

The calibration following a tire replacement is performed automatically.

Recalibration 

Because of the tire abrasion, a constant recalibration of the tire circumference is required. Recalibration is performed automatically.

Recalibration of the tire circumference uses the difference between the calculated and actually traveled distance between two turning points determined with the aid of map-based position finding.

General information on route calculation 

Route calculation is accomplished using the options set to the best possible extent. If observance of the options is not possible, then the options set are ignored for the sections in question and a message is displayed and signaled audibly.

The set criteria and options can be displayed and changed at any time. Acoustic information is output during route calculation: "Route is being calculated". After successful calculation, the route is indicated on the map.

Destination-oriented navigation function sequence 

The integrated navigation processor continuously compares the route calculation data with the position finding data and uses the data to deduce measures for further destination-oriented navigation.

The route guidance is carried out by outputting visual and acoustic information and is divided up into the following areas:

Map route guidance 

Signals for visual depiction of the route guidance (map navigation) are generated by the COMAND controller unit and sent to the audio/COMAND display over LVDS lines. The Audio/COMAND display is switched on via the telematics CAN by the COMAND controller unit.

Destination-oriented navigation through driving lane recommendations 

For certain turnoff situations on multiple-land exit points (e.g. freeway intersection) driving lane recommendations are shown in the bottom line. In addition, when a turnoff recommendation is given, the distance to the actual turnoff point is also displayed by means of a bar graph. The lanes have arrows assigned to them, which indicate on which lane the destination can be reached or the best way to reach it.

With day design, the following colors are valid for representation in the Audio/COMAND display:

Midnight blue: Represents the best or recommended lane.

Light blue: The lane is correct but another lane change will soon be required.

Gray: The lane will not take you to the destination.

IMPORTANT The instrument cluster only displays the midnight blue arrows.

Route guidance by means of voice output 

In vehicles except CODE 810 (Sound system), voice outputs are forwarded by the COMAND controller unit to the speaker system.

On vehicles with CODE 810 (Sound system), the COMAND controller unit 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.

IMPORTANT While voice output is active, the volume of the announcements can be adjusted using the following components, for example: volume control of COMAND controller unit, + and - buttons, adjustment of specific functions and volume control (S111s1) of the right multifunction steering wheel button group.

General information on dynamic route guidance 

With dynamic route guidance ("Dynamic route" or "Eco route") the current traffic situation is taken into account when appropriate traffic data is received. The traffic data recorder in the COMAND controller unit decodes the traffic information and forwards it internally to the navigation processor upon request.

The navigation processor makes the decision whether the route should be changed. If necessary, a message that the route should be changed is output via the speaker system.

Function sequence for dynamic route guidance (except CODE 494 (USA version) and except CODE 498 (Japan version)) 

The FM receiver in the COMAND controller unit receives the traffic messages over the following path, and forwards them to the traffic data recorder in the COMAND controller unit:

Windshield antenna →

FM, AM, CL antenna amplifier and FM 2, DAB and TV antenna amplifier →

COMAND control unit

On vehicles with code 537 (Digital radio (DAB)), the traffic messages received over the DAB band III are forwarded over the following route:

Windshield antenna →

FM 2, DAB and TV antenna amplifier →

Digital Audio Broadcasting control unit →

MOST →

COMAND control unit

The traffic messages are stored in the traffic data recorder of the COMAND controller unit and made available to the integrated navigation processor.

IMPORTANT Model 172.4

up to model year 2017

with code 512 (COMAND APS with DVD changer)

with code B54 (Live Traffic Information)

Model 172.4

up to model year 2017

with code 527 (COMAND APS with single DVD drive (with navigation))

with code B54 (Live Traffic Information)

Dynamic route guidance via RDS/TMC occurs if no real-time traffic data is received (e.g. no valid subscription or the vehicle is not within the geographical area for which the traffic data service is offered).

Function sequence, Vehicle Information and Communication System (VICS) via FM multiplexer (with CODE 498 (Japan version)) 

The driver is provided with vital information by the VICS on the current traffic situation. Traffic impairments and traffic jams are shown on the map, however they are not incorporated into the dynamic route guidance. VICS messages are sent as FM radio signals over the following path:

Windshield antenna →

FM, AM, CL antenna amplifier and FM 2, DAB and TV antenna amplifier →

COMAND control unit

The VICS information is processed in the FM multiplexer integrated into the COMAND controller unit. The information is then displayed on the Audio/COMAND display by means of the low voltage differential signaling line.

Function sequence, VICS dynamic route guidance (with CODE 498 (Japan version), Dealer Option) 

For dynamic route guidance using VICS, the vehicle communicates with the VICS beacons installed at the side of the road (transmitting towers) that send out signals in the reception range of 2.5 Gigahertz and 5.8 Gigahertz (as from 01.06.2013) or infrared signals. Received signals are sent to the COMAND controller unit where they are decoded. The COMAND controller unit stores the traffic messages and makes them available to the integrated navigation processor.

The following components are required for dynamic route guidance:

Function sequence for dynamic route guidance with real time traffic data (RTTD, Real Time Traffic Data) (with code 536 (SIRIUS satellite radio)) 

RTTD is real time traffic data emitted via the "Sirius" satellite radio provider, the reception and processing of which is enabled by the Satellite Digital Audio Radio (SDAR) control unit. The real time traffic data contain 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.

The Satellite Digital Audio Radio (SDAR) control unit receives the real-time traffic data via a direct line from the multifunction antenna and makes it available to the navigation system of the COMAND controller unit via the MOST.

The COMAND controller unit uses the data to calculate alternative routes and displays them on the Audio/COMAND display via an LVDS line.

Additional function requirements for dynamic route guidance with real-time traffic data via the telematics services communications module (with CODE B54 (Live Traffic Information)) 

IMPORTANT Once the subscription has ended, or when outside the geographical area for which the traffic information service is made available, only dynamic route guidance is available with TMC messages over RDS.

Function sequence, dynamic route guidance with real-time traffic data via the telematics services communications module (with CODE B54 (Live Traffic Information)) 

The real time traffic data contains accident and traffic jam messages and traffic flow information, and is available nationwide in the participating countries.

The telematics services communication module receives the real time traffic data from the emergency call system antenna and sends the data over a USB line (Universal Serial Bus) to the COMAND controller unit. The COMAND controller unit uses the data to calculate alternative routes and displays them on the Audio/COMAND display via an LVDS line.

The telematics services communications module requests position data from the COMAND controller unit and transmits it to the service provider via the emergency call system antenna on request. In this way, the telematics services communications module contributes to collating the traffic information from which the dynamic route guidance will then benefit.

Map function 

Map display is always controlled by the COMAND controller unit. The following display functions are supported:

The signals are sent over a low voltage differential signaling line from the COMAND controller unit to the Audio/COMAND display.

  Electrical function diagram for navigation mode (COMAND) function Model 172.4 as of model year 2014 up to model year 2017 with code 512 (COMAND APS with DVD changer)
 
Model 172.4 as of model year 2014 up to model year 2017 with code 527 (COMAND APS with single DVD drive (with navigation))		 PE82.85-P-2063-97TAB
    Model 172.4 up to model year 2014 with code 512 (COMAND APS with DVD changer)
 
Model 172.4 up to model year 2014 with code 527 (COMAND APS with single DVD drive (with navigation))		 PE82.85-P-2063-97TAA
  Overview of system components, telematics   GF82.85-P-9999RD 
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