Laser Doppler velocimeter and its calibration system

A high-precision calibration system for laser Doppler velocimeter (LDV) is designed to calibrate the reference-beam LDV. Larger velocity range, lower velocity uncertainty and smaller alignment error can be provided in calibration process by employing a rotary cylinder with 600 mm radius in the calibration system. Experiments are carried out for detailed analysis. The results show that the relative measurement precision of the LDV under calibration is 0.1% (1 sigma) in the velocity range from 0 to 200 km/h. The main sources of uncertainty in the calibration system are discussed. The expanded uncertainty of the proposed system is 0.03%. The proposed calibrating method can be used in the calibration process for the reference-beam LDV, the dual-beam differential LDV, the self-mixing LDV and the spatial filtering velocimeter. (C) 2018 Elsevier Ltd. All rights reserved.