For velocity measurements use linear optics. Necessary components list:
Optional elements list:
Velocity measurements require optical elements IL1 and RL1 to be aligned along laser beam. Each of the elements can be moved. During velocity measurements our recommendation is to use air temperature sensor. It is not necessary to use base temperature sensors.
Velocity measurements can be performed not only along the laser beam (as shown in the figures above) but also in directions perpendicular to the laser beam. That is to say, in those two configurations move only the retro-reflector RL1.