A method and device for determining with high precision the speed of the rail vehicles

摘要

The invention relates to a method including means for the execution thereof, which can be used to determine the speed of a rail vehicle very precisely from the distance travelled. The output signals (JV1, JV2) of two electromagnetic rail contacts arranged on a rail at a predetermined distance from each other are recorded in digital form, and their time interval is used to calculate the speed. To obtain precise triggering times for time measurement, signal patterns (RJ1, RJ2) reproducing a wheel passage are each optimally approximated by calculation using parabolas (P1, P2), and the co-ordinates of the vertexes of the parabolas are used as the triggering times (tS1, tS2). To check whether both successive signal patterns should be associated with wheel passages, the cross-correlation coefficient between the signal pattern and the approximate parabola can be calculated, and compared with a characteristic set value.