Abstract: The present invention proposes a method and a device for determining a motion parameter of a motor vehicle, a control system (1) for determining, in particular, the instantaneous velocity vector and the angle between the longitudinal vehicle axis and the velocity vector (float angle) is calculated, making use of a differential navigation system (D-GPS) [sic]. Since the differential navigation system (D-GPS) provides considerably more accurate positional data than a ‘normal’ navigation system used in motor vehicles, the determination of the velocity vector of the motor vehicle can also be carried out with greater accuracy. This is relevant, in particular, on a slick roadway when the motor vehicle goes into a skid or when the measured data of the wheel sensor are no longer reliable. In a further embodiment of the present invention, provision is made for the data provided by the navigation system to be also used for checking and monitoring the sensor data.