Radar Derived Joint Statistics of Rain Attenuation in Multiple Locations at Various Distances: Data, Models and Applications

A large data base of point rainfall intensity data collected with the meteorological radar of Spino d´Adda, near Milano, has been used to derive the space-time properties of simulated rain attenuation across a wide area and to investigate the influence of the baseline orientation in various links configurations (including the non-symmetric diversity). Starting from the above mentioned results, a Gaussian model has been fitted on the data and applied in various site diversity schemes: this way, we have been able to study site diversity aspects little investigated so far, such as the baseline orientation effect. Moreover, many models in the literature, like the ITU-R one, are capable to predict site-diversity parameters, such as the diversity gain or the diversity advantage, only for system configurations based on two equal stations, whereas by applying our model to n-plets of links we have been able to estimate the advantage obtainable by non- symmetric satellite systems in double and also in multiple configuration. The results obtained are useful for the performance assessment of resource-sharing fade countermeasures in satellite systems operating at very high frequencies (Ka and Q/V bands), in particular for the design of site diversity schemes in order to counteract rain attenuation in Earth-space paths.