Theoretical substantiation and development of a hardware and software complex for estimating the band of dispersion distortion and the coherence band of fading in a satellite (trans-ionospheric) radio channel based on the results of GPS monitoring of the ionosphere. The basis for solving this problem is the development of a structural-physical model of the radio channel, which allows simultaneously taking into account the phase dispersion and its diffraction in small-scale inhomogeneities of the ionosphere. Analytical dependences of the band of dispersion distortions and coherence of frequency-selective fading on the average value and small-scale fluctuations of the total electron content of the ionosphere are obtained. It is shown that under conditions of ionospheric disturbances, the coherence band of fading can be much smaller than the dispersion band. In accordance with the obtained dependencies, a structure for constructing a hardware and software complex for estimating the dispersion and coherence bands of a satellite radio channel based on the improvement of the GPS-monitoring method of the total electronic content of the ionosphere with small-scale inhomogeneities has been developed