GF82.95-P-3000Q Position Finding, Function
GF82.95-P-3000Q Position Finding, Function
- with CODE (855) TELE AID
- except CODE (498) Japan version
- except CODE (491) USA version
The global positioning system (GPS) is a satellite-supported position finding system set up by the American Department of Defense. It is a toll-free service available throughout the world. The GPS satellites continuously transmit time and position data (longitude/latitude).
Position finding
The vehicle location is determined parallel with two methods supplementing each other. The methods are called GPS position finding and basic position finding.
GPS position finding
GPS position finding is irreplaceable for journeys outside the digitized map area and after vehicle transport (e.g., train or ferry journeys and towing). A new GPS location (after interruption of the satellite reception) can take several minutes (up to approx. 20 minutes when the device is first put into operation). The computer and the GPS receiver unit are integrated in the D2B telephone and TELE AID transmitter/receiver (A35/17). When signals from at least 3 satellites are received by the GPS antenna (A2/23), it is possible to calculate the position and accuracy of the receiver location (vehicle). In addition, the vehicle's direction of travel is determined with the aid of the sequence of the locations calculated with GPS.
Basic location finding
To find the basic position, a process which runs in parallel to the GPS position finding, the D2B telephone and TELE AID transmitter/receiver (A35/17) requires the following information:
^ The signals of the left (L6/1) and right (L6/2) front rpm sensors, that are processed by the ESP and BAS control unit (N47-5) (the number of pulses of the left front rpm sensor (L6/1) is a size for the distance traveled).
^ The data of the yaw rate sensor (gyro sensor) that is integrated in the D2B telephone and TELE AID transmitter/ receiver (A35/17) (the D2B telephone and TELE AID transmitter/receiver (A35/17) uses the data of the gyro sensor to calculate the vehicle's orientation (cardinal point)).
^ The direction of travel data (the signals of the wheel speed sensors and the backup lamp are used to detect whether the vehicle moves forward or backward).
Basic position finding is constantly carried out by the D2B telephone and TELE AID transmitter/receiver (A35/17) with "circuit 15R ON".
The momentary vehicle position (longitude/latitude) is calculated from the path traveled under consideration of the vehicle alignment and direction of motion. If the computer calculates that the basic position finding is less precise than the GPS position finding, the currently calculated position is corrected with the aid of the GPS data. In case of an accident the D2B telephone and TELE AID transmitter/receiver (A35/17) automatically generates an emergency call telegram including the position data of the vehicle and transmits it via the mobile telephone system (D-net) of the vehicle. The emergency call signal reaches the service provider. With the equipment there, the exact position of the vehicle is determined using the position data.
Errors with basic position finding
Rolling backward with the ignition switched off or vehicle transportation also falsify position finding. In both cases, the deviation is automatically corrected by the navigation processor in the D2B telephone and TELE AID transmitter/receiver (A35/17) when the GPS data are received.
