Orbital and site diversity systems in rain environment Radar-derived results

An experiment carried out during the summers of 1981 and 1982 in the Po River Valley, to study the performance of diversity systems for earth-to-satellite links experiencing rain attenuation, is discussed. A meteorological radar simulation of the orbital-diversity (OD) system is performed at 11.6 GHz and comparisons are made with the corresponding simulated site-diversity (SD) system. The OD system, which employs two angularly spaced satellites and one earth terminal site, is effective in the reduction of the overall rain-induced attenuation in a radio link above 10 GHz. The results indicate that the OD gain is significant and that before saturation takes place, an approximately linear relationship exists between the site separation of SD and the orbital-diversity aperture angle yielding the same gain.