Abstract
A ring laser goniometer was investigated in different applications of precision angle measurement, such as the calibration of optical polygons and optical encoders, external angle measurement of rotating objects and inertial angle measurement by rotation of the goniometer itself. The results agree with standard methods of angle measurement to about 0,5 µrad (0,1 ). Further improvement in accuracy is expected mainly from the reduction of noise in the mechanical and electrical setup of the measurement system.