Semidiurnal and long-period components in polar motion connected with the triaxiality of ellipsoids of inertia of the earth and planets

The influence of the Earth's inertia ellipsoid triaxiality: both oil the motion of the Angular Velocity Vector with respect to Tisserand's reference frame thereinafter - AVV,T), the motion of the same vector in Space thereinafter - AVV,S) as well as on the motion of Tisserand's Reference Frame in Space thereinafter - TRF,S) is considered. It is shown that the observable effects are as follows: II) in all three types of motions (AW,T), (AVV,S) and (TRF,S) there are significant (observable) semidiurnal components which may be detected by modern GPS- and VLBI-measurements. Additionally, there is a long-periodic perturbation of (TRF,S) motion which is rather small for the Earth, but may be significant for the other planers of the Solar System (if the triaxiality of the inertia ellipsoid is sufficiently large and whenever the orbital and diurnal rotations are synchronous and, at the points of equinoxes, the orientation of the planer's principal equatorial moments of inertia is invariable in space). For the case of the Earth, the results of our calculations are compared with the results of modern GPS-observations.