Rain-Induced Propagation Parameters For Earth-Space Communication In Nigeria

This paper reports the calculation of rain-induced attenuation along the earth-space path at two elevation angles and some rain rates representing high and low availability requirements in Nigeria. The paper first calculates the slant path scattering parameters at various frequencies and rain rates, and then uses the new ITU-R recommendation P.618-8 to predict the slant path attenuation at the elevation angles of 23o and 55o, which are used frequently for satellite communication in Nigeria. The results obtained show that the old ITU Report 564-4 recommendation could underestimate the total path attenuation by as much 36 dB at a rain rate of 150 mm/h. Some results are also presented for the scattering amplitude functions and propagation constant at the two elevation angles. The parameters of a power-law relationship to calculate the differential propagation constant in terms of the rain rate at the elevation angles are also presented. These parameters when used to calculate the slant path differential propagation constant have a maximum error margin of 1.2% from the actual. Key words: rain-induced attenuation, earth-space path, rain rates, differential propagation constant Nig. J. of Pure & Appl. Physics Vol.3 2004: 28-3