The Doppler frequency shift generated by the change of the solar zenith angle

In this paper we presented the dependence relationship between the solar zenith angle and the height of some layer with some fixed electron concentration in the ionosphere and provided the equations used to calculate the Doppler frequency shift. On the base of the materials obtained through the up-to-date experiments we discussed the influence of the variation of the solar zenith angle to the Doppler frequency shift. The observed quantities well coincided with the theoretical values.