GF82.95-P-3000T Position Finding, Function
GF82.95-P-3000T Position Finding, Function
- with CODE (383) With telephone "Standard" in console on right side of dome with integrated TELEAID emergency call system, hands-free system and antenna
- with CODE (930) Taxi emergency call
- with CODE (934) Taxi emergency alarm unit
Position finding, function
The global positioning system (GPS) is a satellite supported position finding system established by the US Defense Department. 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's position is determined by using two methods simultaneously with each one supplementing the other. The methods are called GPS position finding and basic position finding.
GPS position finding
GPS position finding is particularly valuable when driving outside of the digitized map area and after vehicle has been transported (e.g. train, ferry or towing). A new GPS position (after interruption of the satellite reception) can take several minutes ( up to 20 minutes when the equipment is first set up). With code (383) MB phone "Standard" in the console on the right side of the dome with integral TELE AID emergency call system, hands-free system and antenna, the computer and the receiver unit of the GPS are integrated into the telecommunications control unit (N112). If signals are received from at least 3 satellites via the GPS antenna (A2/49a2) (MODEL 211.0) or via the GPS antenna (A2/23) (MODEL 211.2), it is possible to calculate the position and the accuracy of the position finding of the receiver (vehicle).
Basic position finding
The basic position finding is determined parallel to the GPS position finding. For basic position finding of the vehicle, the telecommunications control unit (N112) requires the following information:
^ The signals processed by the ESP, SPS and BAS control unit (N47-5) from the left front wheel speed sensor (L6/1), right wheel speed rpm sensor (L6/2), left rear wheel speed sensor (L6/3) and right rear wheel speed sensor (L6/4). The number of the particular pulses is a measure of the distance traveled.
^ The data of the yaw rate sensor integrated in the telecommunications control unit (N112). The telecommunications control unit (N112) calculates the vehicle orientation (compass direction) from the data supplied by the yaw rate sensor.
^ The data for the direction of travel (forward or reverse); through the wheel direction signal it is detected whether the vehicle is moving forward or backward.
The basic position finding is performed continuously by the telecommunications control unit (N112) with "Circuit 15R ON" (1/s). 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. If an accident occurs, the telecommunications control unit (N112) automatically generates an emergency call telegram which contains the vehicle position data and transmits this over the vehicle's cell phone system (D-net). The emergency call signal reaches the service provider. With the equipment there, the exact position of the vehicle is determined using the position data.
