Improved models for long-term prediction of tropospheric scintillation on slant paths

Abstract

The prediction models for tropospheric scintillation on earth-satellite paths from Karasawa, Yamada, and Allnutt and ITU-R are compared with measurement results from satellite links in Europe, the United States, and Japan at frequencies from 7 to 30 GHz and elevation angles of 3 to 33. The existing prediction models relate the long-term average scintillation intensity to the wet term of refractivity at ground level. The comparison shows that the seasonal variation of scintillation intensity is well predicted by this relation, but for the annual average some additional meteorological information is needed. A much better agreement with measurement results is found when a parameter representing the average water content of heavy clouds is incorporated. This confirms the assumption that scintillation is, at least partly, associated with turbulence inside clouds. The asymmetry between the distributions of signal fade and enhancement can also be explained by turbulence inside clouds. The asymmetry depends on the intensity of the scintillation, which is consistent with the theory assuming a thin layer of cloudy turbulence. A new model based on this theory predicts the distributions of signal fade and enhancement significantly better.

Measurement and modelling of tropospheric scintillation in Ka/Q band

“…Various statistical models exist for the prediction of the Complementary Cumulative Distribution Function (CCDF) of scintillation intensity (dB) and variance (dB 2 ), using temperature and/or humidity at ground level [1][2][3][4][5][6], profiles [7] or information about clouds [8]. Various measurements have been performed during Olympus and Italsat campaigns in Europe and as well as during other propagation campaigns in tropical climate [9] [10].…”

Simulation of the performance of a Ka‐band VSAT videoconferencing system with uplink power control and data rate reduction to mitigate atmospheric propagation effects

“…Up to now, it has been demonstrated that turbulence-induced scintillation appears either when strong refractive index inhomogeneities occur or in fair weather cumulus. Recent studies have shown that scintillation effect grows with increasing humidity [14] and increasing integrated water content in heavy clouds [15]. Unlike scintillation, oxygen attenuation is present all the time and is not subject to significant variations.…”

Review and comparison of tropospheric scintillation prediction models for satellite communications

“…The van de Kamp models [19,27] are all based on the observation that scintillation is at least partly associated with the presence along the path of heavy cloud. In the first model (Kamp I), the mean water content, W hc (kg/cm 2 ), of heavy cloud (W hc >0.70 kg/m 2 ) is used to provide an additional indicator of scintillation, i.e.…”