Tropospheric Attenuation in GeoSurf Satellite Constellations

Abstract

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° N and 60° S. At the annual probability of 1% of an average year, in the latitude between 30° N and 30° 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° N or 30° 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.

Feasibility of Ultra-Wideband Channels at Millimeter Wavelengths Faded by Rain in GeoSurf Satellite Constellations

“…In [2], we have compared the tropospheric attenuation of GeoSurf zenith paths with the paths of GEO, MEO and LEO satellites.…”

Outage Probability versus Carrier Frequency in GeoSurf Satellite Constellations with Radio-Links Faded by Rain

“…Ref. [2] compared the tropospheric attenuation of GeoSurf satellite paths with those of GEO, MEO, and LEO satellites.…”

“…Compared with ref. [2], in this paper we consider only the zenith paths of the GeoSurf constellation and rain attenuation only, without any further comparison with the GEO, MEO, and LEO radio-links. In fact, our aim is to estimate the relationship between the annual average probability distribution P(A) of exceeding a given rain attenuation A (dB) and the carrier frequency f (GHz)-i.e., the center frequency of bandwidth B w -beyond 16 GHz in the GeoSurf paths (local zenith paths).…”

A Small Power Margin and Bandwidth Expansion Allow Data Transmission During Rainfall Despite Large Attenuation: Application to GeoSurf Satellite Constellations at mm–Waves

“…In designing satellite links above 10 GHz -frequency beyond which the attenuation due to rainfall is no longer neglible -the traditional approach is to consider the average (annual or worst month) probability distribution 𝑃(𝐴) of exceeding rain attenuation 𝐴 (dB) [1][2][3][4][5][6][7][8][9]. In the design, 𝑃(𝐴) is considered the outage probability and 𝐴 (dB) the required power margin necessary to maintain the link working, i.e.…”

“…Moreover, these particular sites are important study-cases because satellite ground stations of NASA and ESA are located there (Fucino, Madrid, White Sands), or because longterm radio propagation experiments were performed at the sites (Fucino, Gera Lario, Madrid, Spino d'Adda), or just because there are large cities (Prague, Norman, Tampa, Vancouver). Following our previous studies of the GeoSurf links [2][3][4][5]28], we simulate 𝐴(𝑡) at 80 GHz (mm-wave), circular polarization.…”