Vehicle Navigation
Vehicle Navigation
General Information and Components
All components in satellite navigation and compound navigation are needed for vehicle navigation. The radio (R) is also needed for trip guidance. The navigation control module uses all the data from the satellite navigation and the compound navigation to establish the actual location of the vehicle. To be even more exact, the calculated route is compared several times every second with the map stored on whatever media is present (CD, DVD, or hard drive).
Function
• The requested route is entered using either the multimedia control head (E380) controls, which are connected to the navigation control module via a serial interface, or by using the optional speech recognition system.
• The location of the end destination is determined using the stored road map.
• The actual location is calculated using GPS data received through the navigation system antenna (R50), which is connected directly to back of the navigation control module by a coaxial cable.
• The location of the vehicle is determined to within +/- 5 meters by compound navigation and comparing to the digital map.
• The radio receives the TMC signal via the RDS channel in the FM band. The radio sends this data to the navigation control module via the MOST-bus.
• The navigation control module calculates the distance, the driving directions, changes in the driving direction, etc., using the TMC information.
• The digital prompts are shown in the front information display control head (J685), which is connected directly to the navigation control module.
• The prompts may be displayed via the instrument cluster control module (J285). The navigation control module also sends the prompts to the MOST-bus. The data bus on board diagnostic interface (J533) then sends these to the instrument cluster control module via the combi/chassis -CAN.
• The digital sound system control module (J525) emits acoustical messages via the connected boxes. Audi output is sent from the navigation control module to the digital sound system control module via the MOST-bus.
• The pulses and change in direction values received from the compound navigation calculate the distance travelled.
• The difference between the reverse gear in an automatic transmission and a manual transmission vehicle is recognized.
Reverse Gear Recognition in Manual Transmission Vehicles
Engaging reverse gear activates the transmission range gear recognition switch (F208). The vehicle electrical system control module (J519) recognizes that reverse gear is engaged by the resistance coding from the switch and then sends the information reverse gear via the data bus.
Reverse Gear Recognition in Automatic Transmission Vehicles
By moving the selector lever, the multifunction switch (F125) tells the transmission to engage reverse gear. When reverse gear is engaged, a message is sent to the transmission control module (J217). The control module transmits the information reverse gear via the data bus. The data bus on board diagnostic interface forwards this information to the MOST-bus and is then evaluated by the navigation control module. The navigation control module recognizes if the vehicle is moving forward or backward.
• The system monitors if the driving prompts are being followed. The driver will be informed if he/she deviates from the recommended route. If the driver remains on this route, then the distance to the final destination will be calculated once again.
• If the navigation control module receives TMC information that affects the route, the route will be calculated again based on these new values. Traffic jams, road construction, etc., on the calculated route will appear as symbols in the front information display control head. Traffic jams, road construction, etc. outside of the route will have a gray background.
• Once the final destination is reached, the driver will hear "You have reached your destination."
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Service Information
• The following applies only to 2nd generation MMI if the vehicle has a navigation system with CD drive control module (J401).
Whenever a DVD is inserted, it will always check if the software on the DVD and in the control module match. If the software is not identical, then the software on the DVD will be flashed onto the navigation control module regardless if it is newer or older. This process is necessary to prevent faults in the navigation system because the software on the DVD is closely connected to the navigation data bank.
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