Date: 28.02.2018., 15:00

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1. Speaker: Dr. Perepelkin V.V.  

Title: Numerical-Analytical Prediction Models of the Earth Pole Motion and of the Irregularity in the Earth Axial Rotation

Abstract:

Based on the spatial variant of the problem “deformable Earth – Moon” in the gravitational field of the Sun and on the astrometric observation data the motion of the Earth pole and the variations of the Earth axial velocity are studied.

Taking as a basis a model of the deformable body, that is close to axisymmetric, a model of the unperturbed motion of the Earth around its center of mass is constructed using the action-angle variables.

A refined prediction model of the Earth pole is developed that takes into account the effects of the spatial motion of “the Earth – the Moon” system, particularly the dependence between the parameters of the Earth pole oscillation process and the precession motion of the lunar orbit.

Based on the deterministic model of the Earth pole motion a combined celestial-mechanical stochastic model of the rotational motion the deformable Earth is developed that takes into account anisotropic fluctuation – dissipative perturbations (stochastic components of the polar tide).

An adaptive prediction model of the Earth axial velocity fluctuation on short time intervals is developed for refining the precision of the coordinate time and navigation systems of a spacecraft. The verification results of the short term prediction model of the Universal time variations dUT1 are presented on a long time interval in comparison with the observation data, obtained from International Earth Rotation and Reference Systems Service (IERS).

The numerical-analytical models of the Earth pole multifrequency oscillational process are presented that are able to improve the precision of the Earth pole trajectory prediction during the time of considerable anomalies (irregular deviations).