Use of ITU-R recommendations in calculating tropospheric signal attenuation in the simulation modeling problems of satellite systems

The problem of taking into accounting the state of the troposphere in determining the possibility of establishing a radio-link between a spacecraft and a subscriber (a station) on the Earth's surface in context of satellite communication system design and operation planning using the simulation modeling is considered. As an alternative to a full-scale troposphere modeling in order to take into account the influence of the atmosphere a method based on the recommendations of the International Telecommunication Union (ITU) of the R-sector P series is proposed to assess the attenuation of radio signal due to such agents as tropospheric scintillations, clouds, precipitations and atmospheric gases. The ITU methods allow to determine the radio-signal attenuation passing through troposphere given the requirements of communication channel availability. The proposed method is based on solving the inverse problem that leads to the construction of the cumulative distribution function of the random value of the energy budget required to overcome described interferences. Using obtained distribution functions given the radio-link energy budget a vector of indicators is generated, reflecting the possibility of establishing a radio link at each step of the simulation modeling.