Applicant:
Prof. Dr. Jürgen Czarske, Dr. Lars Büttner, Thorsten Pfister, Fakultät Elektrotechnik und Informationstechnik, Technische Universität Dresden

Abstract:
Distance is one of the most important measurement quantities in technical applications. Often, optical sensors are applied, since they measure non-intrusive. However, the precise measure-ment of dynamic processes with high temporal resolution was an unsolved task.
The world wide unique laser Doppler distance sensor use a frequency-analogue principle. The spatial variation of two interference fringe systems results in different Doppler frequencies. Their electronic evaluation determines the distance. The laser Doppler distance sensor exhib-its temporal resolutions in the microsecond range. Moreover, the distance resolution is inde-pendent of the lateral velocity of the object, which is an outstanding feature of the sensor. This unique advantage has opened new application areas. For the first time, tip clearance measurements were accomplished with about 20 µm accuracy at about 600 m/s tip velocity.