The present invention relates to a positioning system for a motor vehicle having a satellite receiver.  It is already known from European Published Patent Application No.  496 538 A2 that not only the position of a vehicle but also its direction of travel can be calculated with the help of the satellite receiver.  The direction of travel is determined by calculating the difference between two position determinations.  This method functions satisfactorily only when the GPS positions are measured over great distances, because each individual position is subject to considerable error (in civilian use: approximately 100 m). 
Therefore, it is impossible to determine the direction of travel in real time with this method.  Furthermore, this method assumes little or no coupling sensor error during the GPS measurement; however, that is only rarely the case in practice.