Technology
AcWaCo means Acoustic Wavelength Compensation, a method for determining the momentary refractive index of air along the laser beam path in real time. It works by measuring the speed of sound traveling the laser beam path simultaneously with the length measurement.
The relative effect of a change in the air temperature is about two thousand times stronger on the speed of sound than on the refractive index. Thus AcWaCo detects even the slightest changes to the refractive index and compensates for them, considerably improving the precision of distance measurements made with laser interferometers.