A signal processor for a noncontact speed measurement system

The concept and performance of a new digital signal processor for noncontact, high precision speed and distance measurement of rail-guided vehicles are presented. The measurement procedure is based on the estimation of the time-delay between two signals generated by two optimal sensors located a distance L apart. Due to surface irregularities these signals are random, but nearly identical except for a time delay corresponding to the velocity of the vehicle. The high precision and good dynamical properties of the measuring device are achieved by applying a combination of open-and closed loop correlation techniques and sophisticated digital signal postprocessing algorithms.