  The sensitivity to angular rotation of the top class Sagnac gyroscope
GINGERINO is carefully investigated with standard statistical means, using 103
days of continuous operation and the available geodesic measurements of the
Earth angular rotation rate. All features of the Earth rotation rate are
correctly reproduced. The sensitivity of fractions of frad/s is attained for
long term runs. This excellent sensitivity and stability put Sagnac gyroscopes
at the forefront for fundamental physics, in particular for tests of general
relativity and Lorentz violation, where the sensitivity plays the key role to
provide reliable data for deeper theoretical investigations. The achieved
sensitivity overcomes the conventionally expected one for Sagnac ring laser
gyroscopes.
