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Navigation mode, function - GF82.85-P-2012RF

Model 205 with code 531 (COMAND APS) 

Model 253 with code 531 (COMAND APS) 

Fig 1: Navigation Mode - Function Diagram (Shown On Model 205, 253)
G10134513Courtesy of MERCEDES-BENZ USA

Shown on model 205, 253 

Function requirements for navigation mode in general 

General navigation mode 

The navigation module is integrated in the head unit. The navigation system includes the following functionalities:

The location and direction of movement of the vehicle are continuously 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 (with "Dynamic route", "Dynamic route with confirmation" or "Eco route"): An alternative route is offered under dynamic route guidance, in the event of a sufficiently long traffic jam or road closure on the calculated route.

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.

IMPORTANT Routes (except CODE 498 (Japan version)) or destinations can be transmitted from the Internet via the Mercedes-Benz Application Gateway to the vehicle and transferred into the navigation system.

IMPORTANT In vehicles with CODE 348 (Emergency call/assist system), destination entries and points of interest can be made available to the navigation module of the head unit by the service center. Transfer of this map data is described in the information "Additional telematics services, function".

The navigation system can be activated at the upper control panel control unit.

The upper control panel control unit forwards the control signals as follows:

LCP LIN →

Audio/COMAND control panel →

Telematics CAN →

Head unit

The navigation system can be operated using the Audio/COMAND controller of the Audio/COMAND control panel. The "Back" button supports navigation in the menus. The control signal are transmitted to the head unit by the Audio/COMAND control panel via telematics CAN. The navigation system can be operated with the controls of the left multifunction steering wheel button group and the right multifunction steering wheel button group. The control signals of the left multifunction steering wheel button group and the right multifunction steering wheel button group are forwarded as follows:

Steering wheel electronics →

Steering LIN →

Steering column tube module control unit →

Chassis FlexRay →

Electronic ignition lock control unit →

User interface CAN →

Instrument cluster →

User interface CAN →

Head unit

The navigation system can be operated via the voice control system that is integrated in the head unit. The voice input is picked up by the hands-free system microphone, converted into an electrical signal and forwarded to the head unit via a direct line.

IMPORTANT Additional name lists are provided in the navigation system for the voice control system of the navigation (especially destination entry), e.g. for the following information: place names for selected towns/cities on the data medium, street names for all towns, town centers and points of interest (POIs).

The navigation system can be operated with the touchpad (up to 31.05.2015 with code 531 (COMAND APS), as of 01.06.2015 with code 448 (Touchpad), with code 498 (Japan version) or code 494 (USA version)). The control signals are transmitted to the head unit by the touchpad via telematics CAN.

The navigation function consists of the following subfunctions:

IMPORTANT The navigation system uses a special interface to provide data that is used by other systems in the vehicle. The head unit transmits the data via the user interface CAN.

General Global Positioning System (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.

Additional function requirements for GPS position finding 

GPS position finding function sequence 

The GPS receiver in the head unit receives the GPS signals from the GPS antenna. In vehicles with CODE 348 (Emergency call/assist system), the GPS signals are received by the GPS antenna via the Global Positioning System antenna splitter. The head unit calculates the current position of the vehicle from the GPS signals. The direction of travel is determined with the aid of the sequence of locations calculated with the GPS system.

IMPORTANT Because GPS works in the gigahertz (GHz) range (microwaves) and the signals are weak, the following events may lead to reception interference: Atmospheric interferences (e.g. bad weather, water vapor, fog), multiple 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 higher 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 GPS antenna is therefore not immediately perceptible.

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

Basic position finding function sequence 

For basic position finding the head unit needs signals from the following components:

The data from the Electronic Stability Program control unit is transferred as follows:

Chassis FlexRay →

Electronic ignition lock control unit →

User interface CAN →

Head unit

The data from the sensors integrated in the head unit is forwarded inside the head unit. The current vehicle position (longitude and latitude) is then calculated in the head unit. 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. The deviation is automatically corrected by the navigation processor integrated in the head unit when GPS data is received.

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 ("Route is being calculated") and following successful calculation the route is displayed 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 head unit and sent to the Audio/COMAND display over an LVDS line. The Audio/COMAND display is switched on by the head unit via the telematics CAN.

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 used in the Audio/COMAND display:

White: the best or recommended lane

Light gray: the lane is correct, but a lane change will soon be required.

Dark gray: this lane will not take you to the destination.

IMPORTANT The instrument cluster only displays the white arrows.

Route guidance by means of voice output 

Route guidance by means of voice output is an assistance function that assists the driver without distracting him from the traffic. Voice is output with the selected system language. The destination-oriented navigation of the navigation system is supported by voice outputs with the following information:

Further voice messages take place, for example, at the start of route calculation, when an intermediate destination has been reached, or when the destination has been reached.

During dynamic route guidance, additional voice messages are issued due to traffic messages affecting the route. Special information is issued in some instances by voice output, for example:

The navigation processor of the head unit links word segments to form complete instructions or information during voice output.

IMPORTANT While voice output is active, the volume of the announcements can be adjusted using the following controls: Volume control button of the Audio/COMAND control panel, buttons + and -, adjustment of specific functions and volume control (S111s1) of the right multifunction steering wheel button group.

In vehicles without CODE 810 (Sound system), the voice output is relayed to the speaker system by the head unit.

In vehicles with CODE 810 (Sound system), the head unit transmits the voice output via the MOST to the sound system amplifier control unit. The sound system amplifier control unit amplifies the signals and forwards them to the speaker system.

The volume of the voice output can be adjusted during a voice output using the volume control button in the left lower control panel (with manual transmission) or in the right lower control panel (with automatic transmission).

The left lower control panel (with manual transmission) or the right lower control panel (with automatic transmission) sends the control signal as follows:

LCP LIN →

Audio/COMAND control panel →

Telematics CAN →

Head unit

General information on dynamic route guidance 

Dynamic route guidance takes place in "Dynamic route", "Dynamic route with confirmation" or "Eco route" mode (except CODE 494 (USA version), except CODE 460 (Canada version) and except CODE 498 (Japan version)). During dynamic route guidance the current traffic situation is taken into consideration when appropriate traffic data is received. The traffic data recorder 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.

During dynamic routing with confirmation, the user is notified of the effects of the route change on the travel distance and driving time. The route is only changed with the user's agreement.

If necessary, a message that the route should be changed is output via the speaker system.

Function sequence, dynamic route guidance (except CODE 494 (USA version), except CODE 498 (Japan version) and except CODE B54 (Live Traffic Information)) 

The incoming information about the traffic situation can be received by the Radio Data System/Traffic Message Channel (RDS/TMC) function via FM radio or digital radio (DAB) (with CODE 537 (Digital radio (DAB))) if an appropriate station has been selected.

In model 205.0/1, the FM receiver in the head unit receives the traffic messages via the following route and forwards them to the traffic data recorder in the head unit:

Rear window antenna →

FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier or FM 2 and DAB band III antenna amplifier →

Head unit

On model 205.2, 253, the FM receiver in the head unit receives the traffic messages over FM 1 via the following route and forwards them to the traffic data recorder in the head unit:

Rear spoiler antenna →

FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier →

Head unit

On model 205.2, 253, the FM receiver in the head unit receives the traffic messages over FM 2 via the following route and forwards them to the traffic data recorder in the head unit:

Rear window antenna →

FM 2, DAB and TV 1 antenna amplifier →

Head unit

On model 205.0/1 with code 537 (Digital radio (DAB)), the DAB band III signals are forwarded as follows:

Rear window antenna →

FM 2 and DAB band III antenna amplifier or TV 1 and DAB band III antenna amplifier →

Tuner unit →

MOST →

Head unit

On model 205.2, 253 with code 537 (Digital radio (DAB)), the DAB band III signals are received as follows:

Rear window antenna and FM 2, DAB and TV 1 antenna amplifier →

Windshield antenna and TV 2 and DAB band III antenna amplifier, on vehicles with code 865 (TV tuner) via the TV and DAB antenna splitter →

Tuner unit

The tuner unit forwards the signals to the head unit over MOST.

Function sequence for 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.

The radio antenna signal path is as follows:

Rear window antenna (model 205.0) or rear spoiler antenna (model 205.2, 253) →

FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier →

Head unit

The VICS information is processed in the FM multiplexer integrated in the head unit. The information is then shown over the low voltage differential signaling line on the Audio/COMAND display.

Function sequence for dynamic route guidance with VICS (with CODE 498 (Japan version)) 

The Vehicle Information and Communication System (VICS) control unit and the Dedicated Short-Range Communications control unit are required for dynamic route guidance. The Vehicle Information and Communication System (VICS) control unit contains both the receiver and the antenna. The antenna communicates with the VICS beacons (transmitter masts) installed at the roadside which transmit microwave signals within a 2.5 gigahertz reception range or infrared signals. The received signals are transmitted directly to the head unit and decoded. The Dedicated Short-Range Communications control unit receives VICS signals in the 5.8 gigahertz reception range via the DSRC antenna and forwards them to the head unit. The traffic messages are stored in the traffic data recorder of the head unit, decrypted and forwarded to the navigation processor on request.

Function sequence for dynamic route guidance with Real Time Traffic Data (RTTD) (with CODE 536 (SIRIUS satellite radio)) 

RTTD consists of real-time traffic data that is transmitted through the "Sirius" satellite radio provider and the reception and processing of the data are rendered possible by the tuner 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 tuner unit receives the real-time traffic data via direct line from the SDAR antenna and makes it available to the navigation system of the head unit via the MOST. The head unit uses the data to compute alternative routes and shows it via an LVDS line on the audio/COMAND display.

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 When the subscription has expired or after leaving the area where live traffic data is covered, only dynamic route guidance with TMC messages via RDS is available.

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

The service provider sends the real-time traffic data as follows:

Communications module/stationary heater antenna →

Communications module/stationary heater antenna splitter (with code B24 (Remote control for stationary heater)) →

Telematics services communication module

The telematics services communications module transmits the real-time traffic data via a direct line (Universal Serial Bus (USB)) to the head unit, where it can be used by the integrated navigation processor. The telematics services communications module receives position data from the head unit cyclically via a direct line (USB). The telematics services communications module sends the position data via the communications module/stationary heater antenna to the service provider. The telematics services communications module then contributes to collating the traffic information from which the dynamic route guidance then benefits again.

Map function 

The map display is always controlled by the head unit. The following display functions are supported:

Extended functions for navigation mode 

The navigation system is extended with regard to convenience, customization and tourist information by the following functions:

Data communication between the head unit and the SD card takes place via the USB connection between the head unit and the multimedia connection unit.

The extended navigation mode functions are converted internally in the head unit and - where applicable - shown over the LVDS line on the Audio/COMAND display.

Electrical function diagram for navigation mode (COMAND) function PE82.85-P-2063-97FBA
Overview of system components, telematics GF82.85-P-9999RF 
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