Tropospheric Attenuation in GeoSurf Satellite Constellations

In GeoSurf satellite constellations, any transmitter/receiver, wherever it is located, is linked to a satellite with zenith paths. We have studied the tropospheric attenuation predicted for some reference sites (Canberra, Holmdel, Pasadena, Robledo, and Spino d'Adda), which also set the meridian along which we have considered sites with latitudes ranging between 60 degrees N and 60 degrees S. At the annual probability of 1% of an average year, in the latitude between 30 degrees N and 30 degrees S, there are no significant differences between GEO slant paths and GeoSurf zenith paths. On the contrary, at 0.1% and 0.01% annual probabilities, large differences are found for latitudes greater than 30 degrees N or 30 degrees S. For comparing the tropospheric attenuation in GeoSurf paths with that expected in LEO highly variable slant paths, we have considered, as reference, a LEO satellite constellation orbiting in circular at 817 km. GeoSurf zenith paths gain several dBs compared to LEO slant paths. The more static total clear-sky attenuation (water vapor, oxygen, and clouds) in both GEO and LEO slant paths shows larger values than GeoSurf zenith paths. Both for rain and clear-sky attenuations, Northern and Southern Hemispheres show significant differences.

Automated summary

The passage mainly discusses the connection between transmitters/receivers in the GeoSurf satellite constellations and satellites with zenith paths, investigating tropospheric attenuation at different latitudes. Significant differences were found between the Northern and Southern Hemispheres in terms of clear-sky and rain attenuation under different annual probabilities.