GF82.85-P-2012FQJ Navigation Mode, Function

GF82.85-P-2012FQJ Navigation Mode, Function
MODEL 218
- with CODE (527) COMAND APS with single DVD drive (with navigation system)
- with CODE (498) Japan version

Function requirements for navigation mode in general
^ Circuit 30g ON
^ Signals from at least three Global Positioning System (GPS) satellites present
^ Current navigation data available

Navigation mode, general
The navigation module of the COMAND controller unit (A40/3) enables the vehicle to navigate from its position to the selected destination. Navigation is conducted in the form of a 3D-map display on the Audio/COMAND display (A40/8) as well as verbally over the vehicle's speaker system.
The route is calculated in accordance with the options set.
If it should not be possible to adhere to the options, then the configured options are ignored for the stretch in question and a corresponding message is output visually as well as acoustically.
The set criteria and options can be displayed and changed at any time.
Once the route has been successfully calculated, the route is then shown with the aid of arrow pictograms.
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.
The navigation module is integrated into the COMAND controller unit and contains the following functionalities:
- Position determination
- Route planning, route calculation and destination-oriented navigation
- Visual driving instructions in form of pictograms
- Intersection zoom
- Acoustic driving recommendations
- Display of navigation maps
The location of the vehicle, as well as the direction and distance to the destination are determined by the navigation system once the following information has been entered:
- Place name
- Street
- Intersection or house number (depending on the availability of the data)
- Town center
- Postal code
- Special destinations
- Destination entry via map
The system can be activated or deactivated or the destination and street can be entered using the following components:
- Left multifunction steering wheel button group (S110) and right multifunction steering wheel button group (S111)
- Audio/COMAND control panel (A40/9)
- Control panels on the COMAND controller unit
- Voice control system (VCS [SBS])
The COMAND controller unit receives the control signals from the left multifunction steering group button group and the right multifunction steering group button group as follows:
- Steering wheel electronics (N135)
- Steering LIN (LIN E1)
- Steering column tube module control unit (N80)
- Chassis CAN (CAN E)
- Instrument cluster (A1)
- Interior CAN (CAN B)
When entered using the Audio/COMAND control panel, the control signals are sent via the telematics CAN (CAN A) to the COMAND controller unit. Entries made using the operating panels on the COMAND controller unit are processed within the device.
Voice input is made via the handsfree system microphone (A67b1).
To this end, spoken words are converted into an electrical signal by the handsfree system microphone and forwarded via a direct line to the COMAND controller unit.
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:
- Names for selected cities/towns on the data medium
- Street names for all locations
- Town center

Function sequence for navigation mode
The navigation mode of the COMAND controller unit occurs once the data for the destination and type of route are entered.
The navigation is made up of the following subfunctions:
^ Position finding, function
^ Route guidance function

Position finding, function
The position finding function is divided into the following subfunctions:
Function sequence for GPS position finding
Basic position finding function sequence

Function sequence for 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. An important prerequisite is the synchronicity of the clocks of the satellites and 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.
Since GPS operates in the giga hertz (GHz) range (microwaves) and the signals are weak, reception interference can occur as a result of the following events:
- Atmospheric faults, e.g. inclement weather (fog)
- Multi-path reception due to signal reflections, e.g. from building walls
- Signal blocking, e.g. in built-over areas and in tunnels, by high-rise buildings or trees
GPS signals are received by the GPS receiver integrated into the COMAND controller unit directly from the multifunction antenna (A28/11). The GPS signals are used by the COMAND control 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.

Basic position finding function sequence
Basic position finding runs parallel to GPS position finding. The basic position finding calculation is performed approx. once per second. For basic position finding the COMAND controller unit requires the following information:
- Wheel speed signals
- Distance traveled data
- Vehicle alignment (cardinal points)
- The data for the direction of travel (forward or reverse)
For basic position finding, the COMAND controller unit reads in the following signals from the corresponding components:
- Wheel speeds/wheel rotation direction:
- Left front axle rpm sensor (L6/1)
- Right front axle rpm sensor (L6/2)
- Left rear axle rpm sensor (L6/3)
- Right rear axle rpm sensor (L6/4)
- Steering angle:
- Steering angle sensor (N49)
- Turn rate:
- Turn rate sensor (gyro sensor) (integrated in COMAND controller unit)
The signals from the rpm sensor are provided over the following route:
- Direct line
- Electronic Stability Program control unit (N30/4) (without model 218.374) or Electronic Stability Program Premium control unit (N30/7) (model 218.374)
- Chassis CAN (CAN E)
- Front SAM control unit with fuse and relay module (N10/1)
- Interior CAN
- COMAND control unit
Information on the vehicle direction is sensed and processed internally by the turn rate sensor (gyro sensor) in the COMAND controller unit.
Steering angle information is sent via the following route:
- Steering angle sensor
- Steering column tube module control unit (N80)
- Chassis CAN
- Front SAM control unit
- Interior CAN
- COMAND control unit
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.
Error during position finding due to rolling backward with "circuit 15 OFF" or vehicle transportation falsify 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.
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.
The calibration following a tire replacement is performed automatically.

Route guidance function
The Audio/COMAND display switch-on request is generated by the COMAND controller unit via the telematics CAN (CAN A).
Various options can be selected in the "Navi" menu in the application bar and the menus in the function bar. The set options can be displayed and changed at any time.
After entering or calling up a destination location, route calculation starts. The road between the current vehicle position and the destination is calculated taking the configured options into account. 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 route guidance function is divided into the following subfunctions:
^ Function sequence for static route guidance
^ Function sequence for dynamic route guidance by Vehicle Information and Communication System (VICS) (dealer option)

Function sequence for static route guidance
Once calculated, the route is displayed using arrow pictograms in the Audio/COMAND display and this information is also issued acoustically: "The route is being calculated".
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.
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 is being calculated".
The signals for visual display of the destination-oriented navigation (map navigation) are generated by the COMAND controller unit and sent via a low voltage differential signal (LVDS) line to the Audio/ COMAND display. The following display functions are supported:
- Destination-oriented navigation map
- Positioning map
- Route map
- Scrollable map
- Destination entry map
For particular turn off situations on multilane departures (e.g. freeway intersection) lane recommendations are given in the footer of the Audio/COMAND display. When a turnoff recommendation is given, the distance to the actual turnoff point is also displayed by means of bar graphs.
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.
The instrument cluster only displays the midnight blue arrows.
The driver is also notified of the current traffic situation by the VICS (Vehicle Information and Communication System). The COMAND controller unit receives the corresponding FM signals as follows:
- Rear window antenna structure
- FM 1, AM, CL and KEYLESS-GO antenna amplifier (A2/18)
Traffic impairments and traffic jams are shown on the map, however they are not incorporated into the route guidance.

Function sequence for dynamic route guidance by Vehicle Information and Communication System (VICS) (dealer option)
Dynamic route guidance requires the VICS control unit (A2/37). 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 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 route guidance through voice outputs
The route guidance through voice output function supplements the visual route guidance by the Audio/COMAND display through the following driving instructions being issued by voice output:
- Directional instructions
- Name of the next road to turn into
In addition, special information is issued via voice output in certain circumstances, for example:
- Destination lies in area where driving is only possible to a limited extent
- Route via ferry
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.
During the dynamic route guidance, additional voice messages are issued due to traffic messages influencing the route.
Voice output occurs in the selected system language.
The COMAND controller unit on vehicles without code (810) Sound system actuates the following speakers directly for voice output:
- Left front door speaker (H4/1)
- Left front door tweeter (H4/1h1)
- Right front door speaker (H4/2)
- Right front door tweeter (H4/2h1)
On vehicles with code (810) Sound system, the COMAND control unit transmits the voice signals via the Media Oriented System Transport (MOST) to the sound system amplifier control unit (N40/3). The sound system amplifier control unit then actuates the following speakers via direct lines for voice output:
- Center instrument panel speaker (H4/27)
- Left front door sound system bass speaker (H4/64)
- Front door sound system bass speaker (H4/65)
- Left front door sound system tweeter (H4/68)
- Right front door sound system tweeter (H4/69)
- Left front door sound system midrange speaker (H4/72)
- Right front door sound system midrange speaker (H4/73)

Updating the map data
The map data is installed on the hard disk of the COMAND controller unit. In order to install new card data, this must be copied from a navigation DVD.
If the navigation DVD is inserted in the COMAND controller unit, a prompt automatically appears asking whether the map data is to be installed.
Following confirmation that the map data is to be installed, the installation takes place (t = 10 to 120 min.).
Navigation is only possible following complete installation. If an installation process is interrupted, the installation process can be repeated.
The installation process starts at the point at which the installation process was interrupted.
Following successful installation, a corresponding message appears and the DVD is automatically ejected.
Powering the vehicle electrical system with external voltage with the engine switched off prevents any interruption of the installation process through undervoltage.