Position finding and destination-oriented navigation, function - GF82.61-P-2010LE
MODEL 216, 221 with CODE (527) COMAND APS with single DVD drive (with navigation) as of model year 2009/YoM 08
MODEL 216, 221 with CODE (530) COMAND APS USA (with navigation system) as of model year 2009/YoM 08
Function requirements, general
- Circuit 30g ON
- Signals from at least three Global Positioning System (GPS) satellites present
Position finding and destination-oriented navigation, general
The position finding function and navigation consists of the following subfunctions:
- Function sequence for GPS position finding
- Function sequence for basic position finding
- Function sequence for destination-oriented navigation
- Function sequence for dynamic route guidance
- Function sequence for navigation with lane recommendations
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). The accuracy of the position finding and the actual calculation are based on measuring the runtimes of the signals sent 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. A new GPS position (following interruption of the satellite reception) can take up to several minutes (up to t = 20 minutes when the equipment is initially started up). A new GPS positioning process has to be run after the vehicle has been transported (e.g. by train or ferry or after towing).
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 interference, e.g. inclement weather, water vapor, fog
- Multi-path reception due to signal reflections, e.g. from building walls
- Signal shadowing, e.g. in built-up areas and in tunnels, by high buildings, by trees
The GPS signals are received by the GPS receiver integrated into the COMAND controller unit (A40/3) directly from the telephone and GPS roof antenna (A2/49) (model 221) or from the telephone and GPS antenna (A2/49) (model 216). For vehicles with code (359) TELE AID emergency call system, the GPS signals are relayed to the COMAND controller unit via the antenna splitter (A2/5).
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.
Function sequence for basic position finding
Basic position finding runs parallel to GPS position finding. For basic position finding the COMAND control unit requires the following information:
- Wheel speeds
- Distance traveled data
- Vehicle alignment (cardinal points)
- Direction of travel data (forwards or backwards)
The wheel speeds are recorded by the following components:
- Left front rpm sensor (L6/1)
- Right front rpm sensor (L6/2)
- Left rear rpm sensor (L6/3)
- Right rear rpm sensor (L6/4)
The rpm sensor signals are provided over the following route:
- Direct line
- Regenerative braking system control unit (N30/6) (model 221.095/195)
- ESP control unit (N47-5) model 216, model 221 (except model 221.095/195)
- Chassis CAN (CAN E)
- Central gateway control unit (N93)
- Central CAN (CAN F)
- COMAND control unit
Information on the vehicle direction is sensed and processed internally by the turn rate sensor (gyrosensor) in the COMAND control unit.
Information on direction of travel is provided in the following manner:
- Regenerative braking system control unit or ESP control unit
- Chassis CAN
- Central gateway control unit
- Central CAN
- COMAND control unit
The COMAND control unit uses the distance traveled, the vehicle alignment and the direction of travel to determine the vehicle's current position (longitude and latitude).
This computation is performed approx. every t =1/s.
Location errors during position finding may occur due to rolling backwards with "Circuit 15 OFF" (ignition switched off) or when transporting the vehicle. In both cases, the deviation is corrected automatically by the navigation processor integrated into the COMAND controller unit.
The calibration following a tire replacement is performed automatically. 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.
Function sequence for 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 destination-oriented navigation. The COMAND controller unit sends the audio signals for navigation voice output over the Media Oriented System Transport (MOST) to the audio tuner control unit (N93/1) or the digital sound processor (A2/69) (model 221 as of 1.9.10 with code (811) Advanced Sound System). The audio signals are amplified there and forwarded to the following list of speakers for output.
Model 216:
- Left door speaker group (H4/1) (without code (810) Sound system)
- Right door speaker group (H4/2) (without code (810) Sound system)
- Left door rear speaker (H4/3)
- Right door rear speaker (H4/4)
- Bass module speaker (H4/17)
- Center cockpit speaker (centerfill) (H4/27)
- Left door Sound tweeter (H4/68) (with code (810) Sound system)
- Right door Sound tweeter (H4/69) (with code (810) Sound system)
- Left door Sound woofer and midrange speaker group (H4/72) (with code (810) Sound system)
- Right door Sound woofer and midrange speaker group (H4/73) (with code (810) Sound system)
Model 221 except model 221 (as of 1.9.10) with code (811) Advanced Sound System:
- Left front door speaker group (H4/1) (without code (810) Sound system)
- Right front door speaker group (H4/2) (without code (810) Sound system)
- Left rear door speaker group (H4/3)
- Right rear door speaker group (H4/4)
- Bass module speaker
- Center cockpit speaker (centerfill)
- Left front door Sound tweeter (H4/68) (with code (810) Sound system)
- Right front door Sound tweeter (H4/69) (with code (810) Sound system)
- Left front door Sound woofer and midrange speaker group (H4/72) (with code (810) Sound system)
- Right front door Sound woofer and midrange speaker group (H4/73) (with code (810) Sound system)
Model 221 (as of 1.9.10) with code (811) Advanced Sound System:
- Speaker Left front door (H4/5)
- Right front door speaker (H4/6)
- Bass module speaker
- Center cockpit speaker (centerfill)
- Left front door tweeter (H4/33)
- Right front door tweeter (H4/34)
- Left rear door tweeter (H4/35)
- Right rear door tweeter (H4/36)
- Left rear surround speaker
- Right rear surround speaker
- Left front door woofer (H4/64)
- Right front door woofer (H4/65)
- Left rear door woofer (H4/66)
- Right rear door woofer (H4/67)
The woofers and bass box speaker on model 221 (as of 1.9.10) with code (811) Advanced Sound-System are actuated by the sound amplifier (A2/13), which is controlled by the digital sound processor.
The signals for visually displaying the navigation (map navigation) are generated by the COMAND controller unit and transmitted over a low voltage differential signaling (LVDS) line to the COMAND display (A40/8) (without code (867) SPLITVIEW) or to the SPLITVIEW display (A40/10) (with code (867) SPLITVIEW) where they are displayed.
In addition, arrow pictograms for navigation are displayed in the multifunction display (A1p13) of the instrument cluster (A1). The instrument cluster receives the signals for this from the COMAND controller unit via the central CAN.
Function sequence for dynamic route guidance
The dynamic route guidance considers the current traffic situation. The information concerning the traffic situation is transmitted via FM on a regional basis by specially equipped radio stations and is received by the radio data system (RDS) function or the traffic message channel (TMC) via the FM radio.
The COMAND controller unit processes this information internally in the traffic data recorder and sends the deciphered traffic information on request to the internal navigation processor. The navigation processor makes the decision whether the route should be changed. If necessary, a message that the route was changed is output over the speakers.
Traffic information subject to a fee from "TMCpro" stations is also processed in the background and provided to the dynamic route guidance. The "TMCpro" service is graphically shown by means of a special logo at the bottom right in the navigation map of the COMAND display (without code (867) SPLITVIEW) or the SPLITVIEW display (with code (867) SPLITVIEW).
The FM receiver in the audio tuner control unit or the high definition tuner control unit (N87/8) (with code (517) HD radio) receives the traffic information over the rear window antenna amplifier module (A2/12) and routes it 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 navigation with lane recommendations
In certain turnoff situations (e.g. multilane exits or freeway intersections), lane recommendations are given in the footer of the COMAND display or the SPLITVIEW display. Along with a turnoff recommendation, 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 the lane by which the destination can be reached or the best way to reach it.
For the day design the following colors are used for presentation on the COMAND display or the SPLITVIEW display:
Midnight blue: Best or recommended lane
Light blue: Lane is correct, but a lane change will soon be required
Gray: Lane will not take you to the destination
Only dark blue arrows are displayed in the instrument cluster's multifunction display.
Map display is always controlled by the COMAND controller unit. The following display functions are supported:
- Destination-oriented navigation map
- Position map (details of currently driven road and geo-coordinates, height above sea level and number of currently available satellites)
- Route map
- Scrollable map
- Destination entry map
| Electrical function diagram for position finding and navigation (COMAND), function | Model 216 | PE82.85-P-2062-97CAA | |
| Model 221 | PE82.85-P-2062-97SAA | ||
| Component description for instrument cluster | A1 Model 216.3, model 221 except model 221.095/195 |
GF54.30-P-6000LE | |
| Model 221.095/195 | GF54.30-P-6000LEH | ||
| Digital sound processor, component description | A2/69 Model 221 as of YoM 10 with code (811) Advanced Sound System |
GF82.62-P-5011LE | |
| Component description for COMAND controller unit | A40/3 With code (527) COMAND APS with single DVD drive (with navigation system) |
GF82.85-P-3136LE | |
| With code (530) COMAND APS USA (with navigation system) | GF82.85-P-3136LEU | ||
| COMAND display, component description | A40/8 Without code (867) SPLITVIEW |
GF54.30-P-6110LE | |
| Front central operating unit, component description | A40/9 | GF54.21-P-4500LE | |
| SPLITVIEW display, component description | A40/10 With code (867) SPLITVIEW |
GF54.30-P-6120LE | |
| Component description for regenerative braking system control unit | N30/6 Model 221.095/195 |
GF42.22-P-1100LEH | |
| Component description for ESP control unit | N47-5 Model 216.3, model 221.0/1 except model 221.095/195 |
GF42.45-P-5118LE | |
| Component description for high definition tuner control unit | N87/8 with code (517) HD-Radio |
GF82.60-P-5005LEU | |
| Component description for central gateway control unit | N93 | GF54.21-P-4170LE | |
| Audio tuner control unit, component description | N93/1 Without code (810) Sound system and without code (811) Advanced Sound System |
GF82.62-P-3132LE | |
| With code (810) Sound system Model 221 as of YoM 10 with code (811) Advanced Sound System and without code (494) USA version |
GF82.62-P-3132LES |