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

MODEL 204.0 /2 with CODE (527) COMAND APS with single DVD drive (with navigation) with CODE (512) COMAND APS with DVD changer as of model year 2009 /YoM 08 

MODEL 204.3 /9 with CODE (527) COMAND APS with single DVD drive (with navigation system) with CODE (512) COMAND APS with DVD changer 

Fig 1: Navigation Mode Function Diagram
G07532287Courtesy of MERCEDES-BENZ USA

Function requirements, general 

General 

The navigation module is integrated in the COMAND controller unit.

The navigation system includes the following functionalities:

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 calling up a destination location, route calculation starts. The route between the current vehicle position and the destination is calculated. The following parameters can be selected as an example in the "Mode" menu:

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 is no longer moving on the precalculated route, the route is recalculated. 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.

IMPORTANT Routes (except code (498) Japan version) or destinations can be sent to the vehicle via email from the internet using the Mercedes-Benz gateway application and taken over in the navigation system. Compare also document "Internet connection, function".

IMPORTANT On vehicles with code (359) TELE AID emergency call system, destination entries or points of interest can also be provided to the COMAND control unit navigation module from the service center. Transfer of this navigation data is described in the document "Additional telematic service, function".

The navigation system can be operated with the following components:

When entered using the Audio/COMAND control panel, the control signals are sent 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 signal path for the left multifunction steering wheel button group and the right multifunction steering wheel button group to the COMAND controller unit is as follows:

When operating with the voice control system, voice input is possible with the hands-free system microphone.

Words spoken into the hands-free system microphone are converted into an electrical signal and forwarded via a direct line to the COMAND controller unit.

IMPORTANT For the voice control of the navigation, in particular for destination entry, additional name lists are available in the system. There are also additional name lists, e.g. for the following information:

The navigation function consists of the following subfunctions:

Position finding and destination-oriented navigation 

The position finding and destination-oriented navigation function is divided into the following subareas:

General information on GPS position finding 

The GPS is a satellite-based positioning system. It is available worldwide. The GPS satellites permanently transmit time and position data (longitude and latitude). GPS position finding is irretrievable after vehicle transport (e.g. by train or ferry or after towing). A new GPS position (after interruption of the satellite reception) can take several minutes (up to t = 20 minutes when the equipment is commissioned).

The accuracy of the position finding and the actual calculation is essentially based on the measurement of the runtimes of the signals transmitted synchronously by the various satellites. A vital precondition is the synchronicity of the clocks in the satellites and in the receiver. To this end the receiver is equipped with an automatic time correction, which in turn is made possible with the aid of the satellite signals.

Function sequence for GPS position finding 

The GPS signals are received by the GPS receiver integrated into the COMAND controller unit directly from the multifunction antenna or, on vehicles with code (359) TELE AID emergency call system, by the multifunction antenna via the global positioning system antenna splitter. The GPS signals are used by the COMAND controller unit to calculate the current vehicle position (receiver). In addition, the vehicle's direction of travel is determined with the aid of the sequence of the locations calculated with GPS.

IMPORTANT Since GPS operates in the gigahertz (GHz) range (microwaves) and the signals are weak, reception interference can occur as a result of the following events:

General information on basic position finding 

Navigation can be continued without a GPS signal using basic position finding. A possible defect, e.g. in the multifunction antenna is not immediately perceptible.

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 turn rate sensor (gyro sensor) data in the COMAND controller unit are forwarded within the COMAND controller unit.

The wheel speed signals are received by the COMAND controller unit from the listed RPM sensors via the following route:

After this the COMAND controller unit uses the distance traveled, the vehicle alignment and the direction of travel to calculate the vehicle position (degree of longitude and degree of latitude) at any given time.

The steering angle signal is read in by the control unit for the steering column tube module and via the chassis CAN to the front SAM control unit with fuse and relay module and forwarded from there together with the direction of motion information (forwards/backwards) via the interior CAN to the COMAND control 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. 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. It is carried out automatically and uses the difference between the calculated and actually traveled distance between turning points calculated with the aid of map-based position finding.

General information on route calculation 

On vehicles without code (498) Japan version, certain route sections can be excluded from the route calculation under "Own selection", e.g.:

Certain areas can be excluded from route calculations on vehicles with code (498) Japan version, with "Avoid Area" in the "Settings" menu.

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. After a successful calculation, the route is displayed on the map and this information is then relayed acoustically - "Route calculated".

Function sequence for destination-oriented navigation through voice output 

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.

For vehicles with code (810) Sound system the voice output is sent over the Media Oriented System Transport (MOST), then amplified in the sound system amplifier control unit and forwarded over direct lines to the speaker system.

On vehicles without code (810) Sound system, the route guidance voice output is sent over direct lines via the COMAND controller unit to the speaker system.

IMPORTANT More detailed information on the speaker system is available in the Speaker output function documentation.

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

General information on dynamic route guidance (without code (494) USA version and without code (498) Japan version) 

Dynamic route guidance is performed in the "Dynamic route" or "Eco route" mode (as of 1.3.2011, except model 204.9). The current traffic situation is taken into consideration in the dynamic route guidance. The incoming information on the traffic situation can be received by the radio data system/Traffic Message Channel (RDS/TMC) function via FM radio.

IMPORTANT In the "Eco route" mode (as of 1.3.2011, except model 204.9) a combination of ecological and economic factors is also taken into account during navigation in addition to the current traffic situation.

The information on the current traffic situation is broadcast regionally on FM by a specially equipped broadcasting corporation. A suitable FM/RDS transmitter must be tuned in.

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

IMPORTANT As of 1.6.2009 TMCPro is also available in addition to TMC. In contrast to the public service TMC, TMCPro uses additional exclusive traffic information that is recorded with an automated sensor network. The traffic data received by TMC and TMCPro may differ. Receipt of the respective traffic data is shown at the bottom right in the Audio/COMAND display with the symbol "TMCPro" or "TMC".

Function sequence for dynamic route guidance (without code (494) USA version and without code (498) Japan version) 

The FM receiver in the COMAND controller unit receives the traffic messages from the following antenna amplifiers and transfers them to the traffic data recorder in the COMAND controller unit.

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

Function sequence for 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. The radio antenna signal travels to the COMAND controller unit as follows:

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. On model 204.9 and model 204.0/2 up to 28.2.2011, additional information is received by the FM mutiplexer (e.g. information on weather and earthquakes).

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

Dynamic route guidance requires the VICS control unit. The VICS control unit contains both the receiver and the antenna. The antenna communicates with the VICS beacons (transmitter masts) installed on the road, which transmit microwave or infrared signals within a 2.5 Gigahertz reception range. Received signals are sent directly to the COMAND controller unit where they are decoded. The traffic messages are stored and relayed to the navigation processor.

The traffic data recorder decodes the traffic information and forwards this to the navigation processor upon request. The navigation processor makes the decision whether the route should be changed. If necessary, a message saying that the route was changed is issued.

Function sequence for Real Time Traffic Data (RTTD) (with code (494) USA version and code (536) SIRIUS satellite radio as of 1.6.2009) 

RTTD is an abbreviation for real time traffic data broadcast by the "Sirius" satellite radio provider, whose reception and processing was accomplished by the SDAR/high definition tuner control unit up to 31.5.2010 or by the satellite digital audio radio (SDAR) control unit as of 1.6.2010.

This data is available throughout the USA and is transmitted in t = 5 min loops.

The data contain accident and traffic jam messages as well as traffic flow information. This information is provided to the COMAND control unit via MOST where it is used internally for calculation of alternative routes as well as displayed on the audio/ COMAND display.

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: The best or recommended lane.

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

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

IMPORTANT The instrument cluster only displays the midnight blue arrows.

Map function 

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

Route guidance through voice output 

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

Voice is output with the selected system language.

Special information on the voice output is issued in the following cases:

In vehicles without code (494) USA version, additional information is provided in the following instances:

Further voice outputs take place at the start of the route calculation, when an intermediate destination has been reached, or when the destination has been reached. For vehicles without code (494) USA version, for dynamic route guidance, additional voice messages are issued in response to routes influenced by traffic messages.

IMPORTANT During an active voice output the volume of the announcement can be adjusted by the following components:

The navigation processor of the COMAND controller unit combines the word segments into complete instructions or information during a voice output and generates low frequency (LF) signals.

REFER TO SYSTEM WIRING DIAGRAMS Electrical function diagram for navigation mode (COMAND), function   PE82.85-P-2063-97FAA
  Overview of system components, telematics   GF82.85-P-9999CE 
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