Basic position finding, function - GF82.61-P-3006TU

MODEL 211.0 /2 up to 30.6.06 with CODE (528) HIGH Class USA

Shown on model 211.0

Fig 1: View Of Basic Position Finding

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

With code (527) navigation module for COMAND and code (528) HIGH Class USA the external navigation module is designated navigation processor (N41/1).

Basic position finding is the basic function of continuous position finding. It is carried out constantly by the navigation processor (N41/1) with "circuit 15 ON" and is independent of the DVD map. The current position is stored after "circuit 15 OFF".

The following information is calculated with the aid of basic position finding:

Travel distance covered
Direction of travel (backwards or forwards)
Vehicle alignment

Basic position finding is performed every 1 s.

Direction of travel

Through the wheel rotation direction signal which is transmitted by the ESP control unit (N47-5) and transmitted by the central gateway control unit (N93) to the interior CAN (CAN-B), the navigation processor (N41/1) detects the direction of travel (forwards or backwards).

Distance traveled

The navigation processor (N41/1) also receives the wheel speed signals from the ESP control unit (N47-5). Evaluation of the wheel speed signals results in the travel distance covered.

Vehicle orientation

From the data of the yaw rate sensor (gyro sensor) and the sequence of the locations calculated using GPS, the navigation processor (N41/1) calculates the orientation (compass direction) of the vehicle. The difference between the calculated and actual distance traveled between two turns is used for the automatic recalibration of the tire circumference.

Errors with basic position finding

Rolling with "circuit 15 OFF" or transporting the vehicle likewise falsify location finding.

In both cases the deviation is corrected automatically by the navigation processor (N41/1) upon receipt of the GPS data.

Calibration

Wheel calibration is necessary following a tire change. To do this, the input of tire size, e.g. 225/060/016 and the coding, whether new (depth of tread approx. 5 to 10 mm) or worn tires (depth of tread approx. 3 to 5 mm) have been fitted, is necessary. Entries are made using STAR DIAGNOSIS or directly on the COMAND operating, display and control unit (A40/3). A special calibration journey is not required.

Global positioning system (GPS) position finding, function

GF82.61-P-3007TU