Fade Slope Investigation based on Propagation Data Collected from a MEO Constellation

This paper presents an analysis of the temporal rate of change of tropospheric attenuation, namely the fade slope, affecting Non-Geosynchronous (NGSO) satellite links. The study is based on propagation data collected over a period of 2.5 years, during an extensive experimental campaign conducted within the MEKaP project. Modulated telemetry signals transmitted by the O3b Ka-band Medium Earth Orbit (MEO) constellation were received at three ground stations in Milan, Rome and Aveiro. Dedicated signal processing was applied to extract the carrier power and isolate the corresponding atmospheric attenuation component, enabling a comparative analysis of fade slope distributions for different latitudes and climatic conditions. For each site, the derived fade slope statistics are compared with the model described in ITU-R Rec. P.1623-1, showing good agreement with the expected results.