Contour Mapping for Rain Rate and Rain Attenuation in Microwave and Millimetre Wave Earth-Satellite Link Design in Tropical Tanzania

Abstract

Rain rate and rain attenuation predictions are vital in the analysis of the performance of earth-satellite link at higher frequencies beyond 10 GHz for satellite system planning. This study intended to address lack of rain attenuation profile based on local rainfall data collected from various parts of the country. A one-minute integration time rainfall rate used to estimate the rain-induced attenuation was obtained by converting the annual rainfall data collected for 40 years from 22 locations in Tanzania using a combination of Chebil and refined Moupfouma-Martin methods. The International Telecommunication Union (ITU) standard was used to predict attenuation caused by one-minute rain rate. Contour maps for rain rate and rain attenuation were then generated over different percentages of times of 0.1% and 0.01% for both Ku and Ka-bands using the Kriging interpolation method in ArcGIS software. The maps show higher predicted rain rate values compared to the values given by the ITU in zones K, M and N. The developed maps can be used for rapid and precise estimation of link budget for satellite system design in Tanzania.

Keywords: contour maps; one-minute; rain attenuation; integration time; Ku-band and Ka-bands