Proposed Model for the Estimation of Rain Attenuation: At Ku-Band at Ota, a Tropical Location

Abstract

This study proposes a model for calculating rain attenuation on earth-space path carried out in Covenant University, Ota, Nigeria, a tropical location. The beacon signals from a geostationary satellite - ASTRA 28°E (2E/2F/2G) was monitored, recorded and analysed using a spectrum analyzer operating at frequencies of 12.245 GHz. Rain rates at the station of the antenna receivers were also logged and analysed. The rainfall rate cumulative distributions and the resultant rain attenuation are obtained and presented. The results obtained showed that the cumulative distribution of the measured rainfall rate is not in agreement with ITU-R prediction. Rainfall rate at 0.001 %, 0.01 %, 0.1 % and 1 % were fed into the existing Simple Attenuation Model (SAM) and corresponding rain attenuation were obtained. The measured rain attenuation from the beacon signal was compared with sixteen existing rain attenuation models in literature only SAM model was closed to the measured result at the location. SAM model overestimated and underestimated the rain attenuation for this location at some percentage of time. Hence, a modified SAM model is proposed using newly obtained specific attenuation coefficients. The proposed modified model is found to be close to the measured rain attenuation.