Characterization of Worst Month Statistics for Satellite-Earth Links Performance in Tropical Locations

The increasing development in satellite technology has brought about several novel mobile satellite services and applications. Consequently, there is a pressing demand for seamless data transfer and accessibility to satellite-earth microwave links in SHF/EHF frequency bands. However, rain has been the major degradation parameter for the availability of satellite signals especially at frequencies greater than 10 GHz. In this paper, we present some statistical analysis of rainfall in two tropical locations in Nigeria – Akure (7°17’N, 5°18’E, 358 m) in the Southwest, and Jos Plateau (9°57’N, 8°58’E, 1192 m) in the north central. Rainfall intensities of one-minute integration time were measured for 19 months (June 2013 to December 2014). Predicted results showed that rain induced attenuation values above 30 dB occurred during the worst months, while clear sky values are below 2 dB. The worst month statistics obtained were largely different from those proposed by the ITU. Thus, for optimum link budgeting, the modified values of Q and ß should be adapted in these regions. The results will facilitate improved radio-communication planning in the region. More investigation on beacon measurements of rain-induced attenuation is required to corroborate these results.