Navigation mode, function

D82.85-0113-79

Function requirements, general

 Circuit 30t ON

 Transport mode not active

 Signal reception from at least three global navigation system (GPS) satellites

 No smartphone connected via Android Auto or CarPlay.

Navigation mode

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

 Position finding

 Destination entry

 Route calculation

 Display of navigation maps

 Intersection zoom

 Visual driving instructions in form of pictograms

 Acoustic driving instructions

The location of the vehicle and the direction and distance to the destination are determined continuously with the aid of the navigation system. After entering or selecting a destination location, route calculation starts.

Depending on national version, various options can be selected for route calculation, e.g.: :

 "Fast route"

 "Dynamic route"

 "Eco Route"

 "Short route"

 Avoid options (e. g. "Avoid area", "Avoid tunnel", "Avoid ferries", "Avoid toll sticker roads")

If observance of the options is not possible, they are ignored for the stretches in question. Visual and acoustic signals are also output. The set options can be changed at any time. When the route is being calculated, the message "Calculating route" is output. Following calculation, the route is displayed by arrow pictograms on the Audio/COMAND display. If the vehicle is no longer traveling along the precalculated route, the route is recalculated. If the recalculated values are plausible for the navigation system, then the modified route is displayed.

 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.

In the case of a valid subscription, the navigation system also includes apps with information (e.g. weather, gas station prices) or lists, map data for points of interest (e.g  restaurant, gas station, parking area, shopping), that can be selected as a destination or for a stopover.

 Destinations can be sent from the Internet via the "Mercedes-Benz Application Gateway" to the vehicle and imported into the navigation system.

 Routes can be sent from the Internet via the "Mercedes-Benz Application Gateway" to the vehicle and imported into the navigation system.

 Destination entries or points of interest can be made available to the navigation module of the head unit by the Service Center.

The navigation system can be operated with the following components:

 Audio/COMAND control panel

The Audio/COMAND control panel transmits the control signals via telematics CAN to the head unit.

 Head unit multifunction steering wheel button group

The steering wheel electronics reads in the control signals of the head unit multifunction steering wheel button group directly. The steering column tube module (MRM) control unit reads these in via the steering LIN and transmits these to the instrument cluster via the suspension FlexRay, EZS control unit and user interface CAN. The instrument cluster transmits the control signals of the head unit multifunction steering wheel button group to the head unit via the user interface CAN.

 Voice control system

When operating with the voice control system, voice input takes place using the driver hands-free system microphone. The words spoken are converted into an electric signal and routed to the head unit.

 For the voice control system of navigation, in particular for destination entry, additional name lists are available in the navigation system. Name lists exist for the following information, for example, place names for selected towns/cities on the data storage medium, street names for all towns, town centers and special destinations.

The navigation mode function includes the following subfunctions:

 GPS position finding

 Basic position finding

 Route calculation

 Destination-oriented navigation

 Dynamic route guidance

 Vehicle Information and Communication System (VICS) via FM multiplexer

 Dynamic route guidance with VICS

 Dynamic route guidance with real-time traffic data through the HERMES control unit

 Map function

 Extended navigation functions

 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.

GPS position finding

The GPS is a satellite-based position finding 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 interruption of the satellite reception) 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.

The GPS receiver in the head unit receives the GPS signals from the GPS antenna. 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.

 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).

Basic position finding

If no GPS signal is received during route guidance, navigation is still possible with 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:

 Wheel speed and wheel rotation direction (forwards or backwards) from the Electronic Stability Program control unit

The ESP® control unit transmits information on wheel speed and wheel rotation direction to the head unit via the suspension FlexRay, EZS control unit and user interface CAN.

 Angular velocity of the rotation from the gyro sensor in the head unit

 Ramp detection via the 3D acceleration sensor in the head unit

The head unit calculates the current vehicle position (longitude and latitude) around once per second.

 Location faults during position finding, rolling backward with circuit 15 OFF or vehicle transportation falsify 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.
Because of the tire abrasion, a constant recalibration of the tire circumference is required. Recalibration is carried out automatically and uses the difference between the calculated and actually traveled distance between two turning points that has been determined using map-based position finding.

Route calculation

Route calculation is accomplished using the options set to the best possible extent. If observance of the options is not possible, they are ignored for the stretches in question. Visual and acoustic signals are also output. The set options can be changed at any time. When the route is being calculated, the message "Calculating route" is output. Following calculation, the route is displayed by arrow pictograms on the Audio/COMAND display. If the vehicle is no longer traveling along the precalculated route, the route is recalculated. If the recalculated values are plausible for the navigation system, then the modified route is displayed.

Destination-oriented navigation

The integrated navigation processor continuously compares the route calculation data with the position finding data and uses the data to deduce measures for further route guidance. The route guidance is carried out by outputting visual and acoustic information and is divided up into the following areas:

 Map route guidance

 Route guidance through driving lane recommendations

 Route guidance by means of voice output

Map route guidance

Route guidance via a map is shown on the Audio/COMAND display or the instrument cluster.

The head unit transmits a switch-on request to the Audio/COMAND display via the telematics CAN. At the same time, the head unit generates signals for visually representing route guidance (Map navigation) and transmits these to the Audio/COMAND display via the HSVL line or the corresponding picture signals for a high-resolution visual representation to the instrument cluster via the HSVL line.

Route guidance through driving lane recommendations

For certain turnoff situations on multiple-lane exit points (e. g. freeway intersections), driving lane recommendations are shown in the bottom line. When a turnoff recommendation is given, the distance to the turnoff point is also displayed using 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 on 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.

 The instrument cluster only displays 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 route guidance of the navigation system is supported by voice outputs with the following information:

 Directional instructions

 Name of the next road to turn into.

Further voice messages take place, e. g. 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. In some cases, special information is also issued via voice output in certain circumstances, e. g.:

 Destination lies in area where driving is only possible to a limited extent

 Route via ferry

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

 The announcement volume can be adjusted when voice output is active.

The volume of the voice output can be adjusted during voice output using the volume control button in the lower control panel or in the instrument cluster multifunction steering wheel button group.

The steering wheel electronics reads in the control signals of the instrument cluster multifunction steering wheel button group directly. The steering column tube module (MRM) control unit reads these in via the steering wheel CAN and transmits these to the instrument cluster via the suspension FlexRay, EZS control unit and user interface CAN. The instrument cluster transmits the control signals of the instrument cluster multifunction steering wheel button group to the head unit via the user interface CAN.

Dynamic route guidance

Dynamic route guidance is performed in "Dynamic route", "Dynamic route with confirmation" or "Eco route" mode. 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.

The incoming information on the traffic situation can be received by the Radio Data System/Traffic Message Channel (RDS/TMC) function via FM radio or digital radio (DAB) if an appropriate station is set.

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

The FM receiver in the head unit forwards the traffic messages to the traffic data recorder in the head unit.

Vehicle Information and Communication System (VICS) via FM multiplexer

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 VICS messages are transmitted as FM radio signals.

The VICS information is processed in the FM multiplexer integrated in the head unit. The head unit then transmits the data required for displaying the information to the Audio/COMAND display via the HSVL line.

Additional function requirements for dynamic route guidance with real-time traffic data over the HERMES control unit

 Subscription for real-time traffic data

 The vehicle is located within the geographical area that is covered by the traffic data service.

 At the end of the subscription or outside of the geographical area for which the traffic data service is offered, only the dynamic route guidance with radio traffic messages is available.

Dynamic route guidance with real-time traffic data through the HERMES control unit

The HERMES control unit receives real-time traffic data from the service provider. The real-time traffic data not only include information gathered via satellite support. Via the Car-to-X communication function, information on potential hazards in road traffic are also received, either via the recognition potential of the vehicle sensor system of other Mercedes-Benz vehicles or manually by the vehicle occupants within a radius of 10 km.

The HERMES control unit forwards the real-time traffic data to the head unit. The HERMES control unit receives position data from the head unit at regular intervals. Data exchange between the HERMES control unit and the head unit takes place via a wireless connection between the HERMES control unit's integrated WLAN interface (Wireless Local Area Network) and the WLAN antenna.

The HERMES control unit transmits the position data from the head unit to the service provider. In this way, the HERMES control unit contributes to collecting the traffic information, from which the dynamic route guidance then benefits in turn.

Map function

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

 Route guidance map

 Positioning map

 Route map

 Scrollable map

 Destination entry map

 In vehicles with a valid subscription, software updates can be downloaded online in the vehicle. If software updates are stored on mass storage devices for media, they can be transmitted to the head unit via the multimedia connection unit (A90/5).

Extended navigation functions

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

 Integration of electronic travel guide, accumulation of destinations and downloading of routes via a Secure Digital (SD) card and the SD card slot of the multimedia connection unit

 Special search engine that also makes fuzzy destination entries possible (e. g. parts of destination town, road or points of interest).

 "Route flight" (provides a visual overview of the planned route from a bird's eye view)

 "Drive Show" (sequence of pictures, which show the current position, route, traffic information along the route, vicinity of the destination and the altitude course of the route currently being navigated)

 "Compass" (display of a compass screen, which also contains the geo-coordinates for the current position and the current altitude)

 Possibility to access the Mercedes-Benz "Travel guide" (accessory) via the SD card slot in the multimedia connection unit

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 HSVL line on the Audio/COMAND display.