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

MODEL 204.0/2 as of model year 2009 with CODE 512 (COMAND APS with DVD changer) without CODE 511 (Audio 50 APS with DVD changer) without CODE 525 (MB Audio 50 APS radio) 

MODEL 204.0/2 as of model year 2009 with CODE 527 (COMAND APS with single DVD drive (with navigation)) without CODE 511 (Audio 50 APS with DVD changer) without CODE 525 (MB Audio 50 APS radio) 

MODEL 204.3/9 with CODE 512 (COMAND APS with DVD changer) without CODE 511 (Audio 50 APS with DVD changer) without CODE 525 (MB Audio 50 APS radio) 

MODEL 204.3/9 with CODE 527 (COMAND APS with single DVD drive (with navigation)) without CODE 511 (Audio 50 APS with DVD changer) without CODE 525 (MB Audio 50 APS radio) 

Fig 1: Navigation Mode - Block Diagram
G10084752Courtesy of MERCEDES-BENZ USA

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:

The navigation system enables the position of the vehicle and the direction and distance to the destination to be determined, to do so the navigation system utilizes vehicle data and Global Positioning System (GPS) data.

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 transmitted to the vehicle via email from the Internet using the Mercedes-Benz gateway application and taken over in the navigation system. Compare also information "Internet connection, function".

IMPORTANT On vehicles with code (348) Emergency call/Assist system or code (359) TELEAID emergency call system, destination entries or points of interest can be supplied to the COMAND controller unit navigation module from the Service Center. Transfer of this navigation data is described in the information "Additional telematics services, function".

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 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.

If operation takes place using the remote control (model 204.9 with code (867) SPLITVIEW), the infrared signal from the remote control is received directly by the COMAND controller unit and processed there.

IMPORTANT For voice control of 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, which is available on a global basis. 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). 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 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 ensure synchronicity, the GPS receiver is equipped with an automatic time correction that is controlled by the satellite signals.

Additional function requirements for GPS position finding 

GPS position finding function sequence 

The GPS signals are received directly by the GPS receiver integrated into the COMAND controller unit from the multifunction antenna or, on vehicles with code (348) Emergency call/Assist system or with code (359) TELEAID emergency call system, 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). 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 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 COMAND controller unit receives the wheel speed signals from the Electronic Stability Program control unit over the following path:

The turn rate sensor (gyro sensor) data in the COMAND controller unit are forwarded within the COMAND controller unit. The current vehicle position (longitude and latitude) is then calculated in the COMAND controller 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 except 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. Acoustic information is output ("Route is being calculated") and following successful calculation the route is displayed on the map.

Destination-oriented navigation function sequence 

Route guidance is conducted as follows:

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.

In vehicles except 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 information.

Visual route guidance 

The signals for visual display of the route guidance (map navigation) are generated by the COMAND controller unit, and sent over a low voltage differential signaling line and the AMG Performance Media control unit (model 204.0/2/3 with code (255) AMG Performance Media) to the Audio/COMAND display. The Audio/COMAND display switch-on request is generated by the COMAND controller unit over the telematics CAN.

IMPORTANT Visual route guidance in the instrument cluster is also possible if it has been selected here. The instrument cluster receives the signals via the interior CAN from the COMAND controller unit.

General information on dynamic route guidance 

Dynamic route guidance is executed in the "Dynamic route" or "Eco route" mode (except code (494) USA version and except code (498) Japan version, as of 1.3.2011, model 204.9 as of 1.6.2012). 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. If necessary, a message that the route should be changed is output via the speaker system.

IMPORTANT In the "Eco route" mode a mixture of ecological and economic factors is taken into consideration for the route guidance along with the current traffic announcement.

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

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) if an appropriate station has been selected. 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 received over DAB are routed by the Digital Audio Broadcasting control unit (with code (537) Digital radio) over MOST to 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.

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 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 through the low voltage differential signaling line and the AMG Performance Media control unit (model 204.0/2/3 with code (255) AMG Performance Media) on the Audio/COMAND display. The FM multiplexer receives additional information (e.g. on weather and earthquakes).

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

The VICS control unit and, in vehicles as of 1.6.2012, the Dedicated Short-Range Communications control unit, are also required for dynamic route guidance. A receiver and an antenna are integrated into the VICS control unit. The antenna integrated into the VICS control unit communicates with the VICS beacons (transmission masts) mounted at the side of the road, which transmit microwaves in a 2.5 gigahertz reception range or infrared signals. Received signals are transmitted directly to the COMAND controller unit where they are decoded.

The Dedicated Short-Range Communications control unit receives VICS signals in the 5.8 gigahertz reception range via the ETC/DSRC antenna and forwards them to the COMAND controller unit. The traffic messages are stored and relayed to the navigation processor.

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

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. Real-time traffic data are available in the USA in areas surrounding the metropolises, and they are transmitted roughly every 5 minutes; they contain accident and traffic jam messages as well as traffic flow information. The real-time traffic data are sent to the COMAND controller unit over MOST where the data are used internally for calculation of alternative routes as well as displayed on the Audio/COMAND display.

Function sequence for dynamic route guidance with real time traffic data via the telematics services communications module (with code (B54) COM module) 

On model 204.0/2/3, the telematics services communications module receives the real time traffic data over the emergency call system antenna from the service provider. On model 204.9 the telematics services communications module receives the real time traffic data directly over the integrated transmitter/receiver module. The telematics services communications module forwards the real time traffic data over a direct line (universal serial bus (USB)) to the COMAND controller unit.

The COMAND controller unit sends position data cyclically via a direct line (USB) to the telematics services communications module. The telematics services communications module sends the position data over the integrated transmitter/receiver module (model 204.9) or over the emergency call system antenna (model 204.0/2/3) 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.

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 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.

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 function using voice output is an assistance feature that supports the driver without distracting him/her from the traffic situation. The navigation system's route guidance is supported by voice output using the following information:

Voice is output with the selected system language.

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

For vehicles except 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. On vehicles except code (494) USA version, for dynamic route guidance, additional voice messages are issued in response to routes influenced by traffic messages.

IMPORTANT When voice output is active the announcement volume can be adjusted using the following components:

The COMAND controller unit's navigation processor links word segments during a voice output to form complete instructions or information.

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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