**7.4.2 Proposed solutions**

The proposed methods are based on the presentation of a number of known UT1 observations data at long periods of 100 years or more in form of a superposition of a large number of harmonics. Such an approach contradicts to some extent the currently prevailing point of view that non-periodic trend variations in the Earth's rotation speed influence much more than periodic components of the Earth's rotation irregularity. For example, according to data cited in (Belotserkovskiy, Kaufman, 1972), contribution to the overall universal time prediction error of 1 year due to the unpredictable trend variations is about 99% compared with the contribution due to the imperfection of tidal and seasonal models of the Earth's rotation speed variations. It allows to make an unequivocal conclusion that the only way to improve the reliability and accuracy of the ERP prediction is connected with a solving of the problem and a development of the prediction method most sensible to recent trend variations. According to the authors' investigations, the creation of such model is possible only subject to involvement of as much as possible known data for estimation of the prediction parameters.
