Rain attenuation at low elevation angles: A step towards a LEO time series generator

Rain attenuation is the most critical source of impairments in satellite systems operating at frequencies above 10 GHz. At low elevation angles the attenuation increases severely and its modeling requires a specific formulation in addition to simple geometric scaling. In systems based on Low Earth Orbit (LEO) satellites where the link moves from very low elevations up to highest ones, the knowledge on the characterization of rain attenuation at these low elevations is essential. This paper presents a model able to generate time series of rain attenuation at low elevation angles. The procedure uses rain attenuation episodes obtained from the ITALSAT database at 39.6 GHz and 37.7° elevation and is able to generate time series that reproduce the complementary cumulative distribution function (CCDF) of rain attenuation down to 5°. The paper presents some preliminary results obtained with this procedure. This is a fundamental step towards the development of a LEO Rain Attenuation Time Series Generator.