  The method is based on four fundamental features. The total spin precession
frequency in the vertical plane due to the electric and magnetic dipole moments
in an imperfect ring in a vertical plane is measured. The position of the ring
elements is unchanged from clockwise to counter-clockwise operation. The
calibration of the effective Lorentz factor using the polarization precession
frequency measurement in the horizontal plane is carried out alternately in
each CW and CCW operation. And the approximate relationship between the
frequencies of the polarization precession in different planes is set to
exclude them from mixing to the vertical frequency of the expected EDM signal
at a sensitivity level approaching $10^{-29}$ $e\cdot cm$.
