Daily dependence of x-band radio signal attenuation between geostationary satellite and earth terminals

Subject and Purpose. Statistical data on how the satellite signal level varies with changes in the characteristics of tropospheric layers and lower-troposphere hydrometeors serve designers a useful guide in the development of systems for diagnosing weather conditions and hydrometeor characteristics. The aim of the work is to generalize results from the long-term research into daily dependences of X-band radio signal attenuation between the geostationary satellite and Earth terminals. On this basis it is possible to find relationship between signal level changes at the point of reception and geophysical atmospheric agents. Methods and methodology. A receiving measuring and recording complex developed by the authors is employed for the purpose of establishing relationship between geostationary satellite signal level at the receiving point and geophysical atmospheric agents. Results. A block-diagram of the receiving measuring and recording complex is presented, its operation described. Geometric parameters of the radio signal path of propagation have been considered. Signal level measuring results obtained using a Hot Bird geostationary satellite in the period from 03 to 17 January 2019 have been generalized and interpreted. Conclusions. X-band radio signal attenuation on the path from a geostationary satellite to the Earth has a daily dependence. The radio signal level variations are not connected with alterations in spatial and technical parameters of the geostationary satellite or receiving equipment. The day and night changes in radio signal level are attributed to different daytime durations and different angles of sunbeam (including twilight) incidence on tropospheric areas associated with the receiving antenna pattern in the propagation direction, which entails changeable temperature regime and moisture content in these areas. Geophysical agents in the highest tropospheric layers insolated from far beyond the horizon can also be interpreted for long-distance tropospheric radio wave propagation in these tropospheric regions.