Navigation mode, function

The functional purpose of the navigation system described here is to provide navigation features in the vehicle.

These features essentially include:

 Position determination

 Route planning, route calculation and navigation

 Visual driving instructions in the form of pictograms or maps

 Acoustic driving instructions

The navigation data are compiled and processed essentially in the navigation processor (N41/1). This data is then transmitted via the optical bus (MOST) to the COMAND operating, display and control module (A40/3) or to the sound amplifier (A2/13). The information transmitted is defined in the corresponding interface specifications in the form of APIs (Application Programming Interface).

Function requirements

After successfully starting up for the first time, the navigation system in the vehicle is operational once circuit 15R is active. The navigation-DVD can be removed and inserted (circuit 30 active) at any time

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are detected. However, data are only read in once circuit 15R is active.

Basic navigation

Position determination

Once circuit 15R is active, the navigation system compares the GPS data provided by the GPS antenna with the stored vehicle position data and universal time. The result is the vehicle's position determination accurate to approx. 10 m. If then the vehicle position is requested via the COMAND operating, display and control module (A40/3), it is shown on a map on the display of the COMAND operating, display and control module (A40/3). In addition, the position can also be given in degrees longitude and latitude.

Destination address entry for route calculation

The following information can be used for entering the address:

 Town name

 Street, depending on the extent of digitization

 Intersection (including road number)

 House number (depending on the availability of the data)

 Town centers

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 Town districts with their own street index (depending on the availability of the data)

 Country (for multiple country DVD)

 Destination entry using map

Entry assistance via a predictive speller (strip of letters) is also supported by the system. Depending on the progress of the entry, only those characters are made available that can be entered next. Unique names can be completed automatically, if possible. The corresponding information is provided by the navigation system. The narrowing down by the intelligent speller takes place likewise for special characters and lower-case letters. When entering the house number, a direct number entry is possible; depending on the digitization; however, the number or the corresponding range of house numbers is selected.

When entering town centers without their own district boundaries, the main town is also provided as information. The automatic definition of the selected district can be carried out, if required, via the COMAND operating, display and control module (A40/3).

Route calculation

After entering or calling a destination location, route calculation starts. The route between the instantaneous vehicle position and the destination is calculated in the navigation processor. The computing models: "fastest route", "shortest route" and "dynamic route" can be selected. After a successful calculation, the route is displayed on the map and there is an acoustic information output - the route is calculated.

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Journey on the calculated route

The actual position is compared cyclically in the navigation processor with the predicted position. Input parameters are the GPS-data as well as the data from the yaw rate sensor (GYRO) built into the navigation processor and the data coming from the vehicle for direction of travel and speed. If the vehicle is moving on the pre-calculated route, then all the necessary information is communicated to the driver visually on the display and acoustically via the vehicle speakers. On reaching the destination, the function ends.

Leaving the calculated route

If the vehicle is no longer moving on the pre-calculated route, then the route is recalculated. If the recalculated values are plausible for the navigation system, then the modified route is displayed.

If the recalculated values are not plausible, then the message OFF ROAD is given on the display and the system tries to calculate a new route.

Points of Interest (POI)

POIs can be selected according to the following criteria:

 In vicinity of location

 Surrounding area of actual destination

 Surrounding area of a specific location center

 National POIs

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 The search radius for a POI in a category is usually 20 km, however certain categories, e.g. airports, have a larger search radius (approx. 80 km).

 In areas with a particularly high density of POIs, a search radius of 20 km cannot be guaranteed.

 The selection of POIs from the map is controlled entirely by the HU. The navigation system supplies the map data required.

Travel guide

The COMAND operating, display and control module (A40/3) calls the information from the navigation system. After selecting a travel guide object, this can be incorporated into the navigation system as a current destination. Travel guide destinations may contain the following information:

 Name of the POI (required criterion)

 Geographic coordinates of the POI, if navigation to the destination is possible

 Access coordinates depending on the state of digitization, if the geographic coordinates are a considerable distance from the street network

 Town name

 Street name

 House number

 Phone number

 Other text information

 Supplementary attributes, such as search and filter criterion

 Hierarchical structure for subdividing into higher- and lower-level categories

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Tank range function

The tank range function for gas stations with 24h-opening times is implemented by the navigation module if such gas stations are provided in the POI list. The function is essentially based on the following procedure:

 The COMAND operating, display and control module (A40/3) requests a POI list sorted according to distance as the crow flies.

 Through sequential application of the route search, the route distances to the individual POIs are calculated and buffered in the COMAND operating, display and control module (A40/3).

 The selection of a destination from a prepared list can either take place automatically through the COMAND operating, display and control module (A40/3) or be influenced interactively by the user.

Destination memory

The management of destination memories, address books and intermediate destinations does not take place in the navigation system, but instead in the COMAND operating, display and control module (A40/3). All the methods for entering a destination are available for making entries into this memory. In addition, the current vehicle position can be called for use as a return point.

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External destination specification by telematics services

(via telephone)

If correspondingly enabled and on the driver's request, it is also possible to enter a destination using an MB-telematics service.

The data is transmitted to the vehicle via the telephone (GSM). The external specification of a destination is processed by the COMAND operating, display and control module (A40/3). The same methods as for entering a destination using the map are available.

Voice output

The following languages are available:

 German

 British English

 American English

 French

 Spanish

 Italian

 Dutch

 Swedish

 Danish

 Portuguese

Voice outputs are given for:

 Turning recommendations

 Numbered roads, restricted to highways and federal highways in Europe

 USA oad numbers of interstates, US and state

highways

 Compass point in the USA (north, west, south, east)

A special instruction for areas is given with:

 Destination in area not open to traffic

 Destination in area with restricted traffic access

 Route via ferry

 Route via toll road

Further announcements:

 Start of route calculation

 Destination / intermediate destination reached

 General information: influencing the route based on traffic announcements.

Voice control system

The system can be controlled by voice by spelling out or entering complete words. For the navigation system voice control, in particular for destination entry, additional tree-structured name lists are available. The letter hypotheses of the voice control system are made available to the navigation system via MOST.

The following lists are available for the voice control system:

 Town name list for all town/village names on the data medium

 Street name list for all towns/villages

 List of the relevant intersecting street

 Town center list