Angle metrology at INRIM in the framework of the EMRP Project SIB58

In the framework of a European Project, focused on the improvement of the traceability of angle measurements to the SI unit radian, the Italian Institute of Metrology (INRIM) will develop three new devices. An angle standard used to calibrate angle artefacts, angular encoders and autocollimators (AC), a small angle generator used to calibrate electronic levels and ACs and a reference interferometer used to measure small tilts. The resolution and accuracy target of the three devices is of the order of 0.01” (50 nrad). The working principle of the three devices and the preliminary results are reported.