GF82.85-P-3132TX Navigation Processor, Component Description

GF82.85-P-3132TX Navigation Processor, Component Description
- with CODE (527) COMAND APS with single DVD drive (with navigation)
- with CODE (530) COMAND APS USA (with navigation system)

Component Identification:

Location
The navigation processor is installed in the luggage compartment on the left behind the side paneling.

Task
The navigation processor is responsible for the provision of navigation information in the vehicle.

Design
The navigation processor consists of the integrated function units listed in the following:
^ Global positioning system (GPS) receiver
^ Central computer for route calculation, destination-oriented navigation, and evaluation of sensor and GPS data
^ Digital versatile disk (DVD) drive
^ Turn rate sensor (gyrosensor)

Function
When the driver door is opened, navigation is already activated automatically via the Controller Area Network bus class B (interior) (CAN-B) and thus position finding is started. If, as a result of this, no status change occurs at the EIS [EZS] control unit (N73) (e.g. circuit 15C, circuit 15R ON), the navigation processor remains activated for t = 30 min.
During navigation mode, the navigation processor supplies all the necessary data and information to the COMAND operating, display and controller unit (A40/3) via the Media Oriented System Transport (MOST). In the process, the direction changes of the vehicle are calculated by the integrated yaw rate sensor (gyrosensor) and forwarded internally to the central computer. The control of the navigation processor takes place in the COMAND operating, display and controller unit. All calculations for position finding, route calculation and navigation are performed in the navigation processor.The output of driving instructions takes place in the form of pictographs and as a digital map.

External information
As an interface between CAN-B and MOST, the audio gateway control unit (N93/1) supplies the external information to the other MOST components. The following information is required:
^ Circuit status (e.g. circuit 15R ON, circuit 15 ON)
^ Wheel revolution and wheel direction of rotation
^ Diagnostic data

Diagnosis
When the COMAND operating, display and controller unit is switched on and during operation, the individual subfunctions and navigation components are monitored. Faults that may have occurred are stored in the fault memory and can be read out using STAR DIAGNOSIS.

Destination memory and intermediate destinations
Administration of destination memories, address books, and intermediate destinations takes place in the COMAND operating, display and controller unit.

Map display
The digital map display is always controlled by the COMAND operating, display and controller unit.

GPS receiver
The GPS receiver is a part of the navigation processor. It evaluates the satellite signals coming from the GPS antenna (A2/49a2) and uses them to calculate the vehicle position.