Abstract: According to the invention, an in-vehicle device for evaluating received position signals from at least one transmitter located outside a vehicle is proposed, which from subsequently ascertained position data determines various motion parameters of the vehicle. These motion parameters, such as the vehicle speed, acceleration, and change in rotational and directional angles are used to control devices for the vehicle or the engine. For instance, from the ascertained speed signal, an ABS brake system [!] or a vehicle speed limiter [cruise control?] can be controlled. Alternatively, the motion parameters can be output on a display.