A revised model for the prediction of differential rain attenuation on adjacent Earth‐space propagation paths

Abstract

The main propagation effect on interference between adjacent Earth‐space paths is differential rain attenuation. In the present paper, a revised method to predict the rain differential attenuation statistics is proposed which is based on a model convective rain cell structure of the rainfall medium and the assumption that the point rainfall statistics follows a lognormal form. Moreover, the revised model analyzes the general problem of differential attenuation taking into account the difference of elevation angles of the slant paths under consideration. The numerical results are referred to the interference problem from an adjacent satellite located in symmetrical geostationary positions in relation to the intended satellite and examine the significance of the difference of elevation angles for various parameters of the problem.

Differential Rain Attenuation Statistics Including an Accurate Estimation of the Effective Slant Path Lengths

“…For the examined case, we have considered f = 12 GHz , θ d = 3 • , M = 10 dB and elevation angles ranging from 10 • to 30 • . As it can be seen, the deviation between the present results and the existing ones [3,5] is rather insignificant for satellite paths corresponding to ϕ = 30 • elevation angles (Fig. 4).…”

“…The interfering path has also ϕ 2 = 10 • . In the same figure, the results taken from the existing predictive procedures [3,5] are also drawn. As can be seen, the comparison shows a tendency of better approximation in relation to the already existing predictive results.…”

“…(b) All the other assumptions concerning the point rainrate statistics, the specific rain attenuation (A o = aR b ) and the horizontal structure of the rainfall medium are the same as those employed for the analysis of the previous methodology [3,5]. For the latter consideration, we assume that the convective raincells model proposed by Lin [7] is taken to be valid with respect to effective slant path lengths EK 1 and EK 2 .…”

“…and the analytical expressions for H 2 can be found elsewhere [3], where the constant 0 • isotherm for the rain height has been considered (see expression (3)). The other terms of (24) are complicated but analytical expressions of R m , S r ; a, b, G, c i , d i , ϕ i and are presented in Appendix C, where details for their derivation are also included.…”

“…As suggested by CCIR [2], the above model although simple is provisional and must be used with caution. For this reason, Kanellopoulos et al [3] have proposed a more general predictive method for the evaluation of the differential rain attenuation statistics based on a model of convective raincells and the lognormal assumption for the point rainfall statistics. In the above analysis, a simplified constant rain height equal to the height of the 0 • C isotherm, dependent upon the latitude of the location [4], has been used.…”