Due to the high accuracy and the brilliant long-time-stability LDV systems are especially adapted as reference standard for the calibration of sensors. For this application ILA R&D GmbH has developed – in collaboration with PTB Braunschweig – LDV systems which have established itself as a standard-tool in the area of calibration of speed sensors. Through the close cooperation with Westenberg Engineering, a manufacturer of calibration wind tunnels, LDV systems and wind tunnel can be optimally adapted and if required be delivered from one source.
Figure 1 shows the use of an LDV system based on a HeNe-laser within an accredited wind tunnel at Westenberg Engineering. Due to the high beam-quality particularly LDV-systems with HeNe-lasers have a low measurement uncertainty and a particularly high long-term-stability. For higher laser power Nd:Yag-lasers are used with different wave-lengths up to max. 500mW.
Figure 2 shows an ILA LDV-System with a 75mW Nd:Yag-Laser in a calibration wind tunnel of the PTB Braunschweig. This measuring system has been developed especially for an international key comparison of NMIs (National Metrology Institute) on the issue of flow velocity. After using the system over one year in different NMIs worldwide the system returned to the PTB with a certified uncertainty less then 0,1%.
Fig. 1: HeNe-LDV system in a calibration wind tunnel of Westenberg Engineering, Cologne