Analysis of the errors in the results of radio probing of the dayside ionosphere of Venus caused by its nonsphericity

On the basis of a model of the dayside ionosphere of Venus constructed from data of dual frequency radio probing, the authors analyze the errors of the determination of electron concentration which arise when the spherically symmetric approximation is used. The error produced by the variations of the solar zenith angle along the radio beam in the ionosphere has practically no effect on the distribution of electron concentration in the region of the main and lower maxima of ionization, and it is a maximum when the orbital plane of the spacecraft lies in the ecliptic plane and is a minimum when the sun-Venus-earth angle is 90 degrees