The INRIM - INFN Ring Laser Gyroscope for Planar Angle Metrology Application

We present the main characteristics of a new kind of laser goniometer being developed by a collaboration between INRIM and INFN. The target is an absolute accuracy of 10 nrad, being the present accuracy of the most precise angular encoders at the level of some 100 nrad. Our key idea is to setup a square laser cavity of 0.5 m in side, making use of the last generation dielectric super-mirrors employed in the larger gyroscopes for seismology and geophysics.