P.F. Denisenko - Dr. Sc. (Phys.-Math.), Professor, Head of Department of radiophysics and space research, Research Institute of Physics SFU (Rostov-on-Don). E-mail: denis@ip.rsu.ru
N.A. Koledin - Post-graduate Student, Faculty of physics, Southern Federal University (Rostov-on-Don)

The analysis of the temporal variations of the level of the signal with a frequency of 9,996 MHz on mid-latitude route Moscow - Rostov length of about 950 km has been performed. Consider three methods of trends selection: statistical least squares method (LSM), SSA-method (Singular Spectrum Analysis) and wavelet analysis. LSM is based on representing the trend as the sum of orthonormal polynomials. The maximum degree of the polynomial is determined using Fisher's exact test. The criterion for bypass expansion terms with insignificant coefficients. SSA method is based on the analysis of the eigenvalues of the matrix and the orbital grouping of partial solu-tions corresponding to these eigenvalues. In order to highlight the trend a one-dimensional multi-level wavelet decomposition of the signal E 4 Daubechies wavelet order is used. The trend was by restoring the signal approximating coefficients and coefficients of detailing. It is determinates that they all give similar results. However, SSA-method and wavelet analysis give acceptable results only in the interactive mode. It is not possible to automate the processing of large amounts of data. Therefore, our preference is given to the LSM method using Fisher's exact test to determinate polynomial degree.