GF82.61-P-2002PJ Continuous Position Finding, Function

GF82.61-P-2002PJ Continuous Position Finding, Function

MODELS 203 up to 23.4.04
- with CODE (352a) COMAND operating and display system
- with CODE (498) Japanese version

Continuous position finding
Continuous position finding refers to the calculation of the vehicle's current position. It is already active when the ignition is switched on (circuit 15 ON), and is performed by the navigation processor in the COMAND operating, display and control unit (A40/3). During the switch-on phase (software is loaded), only basic position finding (dead reckoning) is available. After switching off the ignition, all important location finding parameters remain stored for a shut-off delay period of t = 30 min. After switching on the navigation system 4 satellites are required for accurate position finding by the Global Positioning System (GPS). For the following calculations 3 satellites suffice.

After pressing the "Current Position" button the vehicle's current position is shown on the navigation map.

The data of the ESP and BAS control unit (N47-5), gyrosensor and GPS receiver are used by the navigation processor to constantly calculate the position. Evaluation of the vehicle movement is mapped as a vector according to route and angle. Position finding is executed by comparing these vectors with the digital street data stored on the navigation Digital Versatile Disk (DVD).

It is not necessary to enter the tire size (parameterization).

The location of the vehicle is continuously calculated by the navigation system using the following 3 methods:
- Basic position finding (dead reckoning)
- GPS position finding
- Map-supported map matching

The 3 methods are reciprocally compared in the navigation processor.

For journeys in areas in which the time zone change has to be considered, then the current time has to be set to match the GPS position finding. This applies equally to summer and winter time. Setting the time is performed on the COMAND operating, display and control unit (A40/3) and transmitted to the clock on the instrument cluster (A1).

It is possible to enter the location manually on the COMAND operating, display and control unit (A40/3) This may be useful if there was no GPS reception at the start of the journey or after the vehicle has been transported (e.g. ferry or train).