Radar estimates of attenuation at 30 GHz: comparisons with Olympus beacon measurements

Radar can play two important roles in studies of rain-induced propagation effects on communications systems. Analysis of individual events an lead to a better understanding of the physical mechanisms involved, whilst a large database can be used to provide statistical information by simulating particular systems. Both approaches provide valuable information relevant to the modelling process. The successful launch of the Olympus satellite has provided a new opportunity to investigate the effects of rain and other hydrometeors on slant path propagation. Of particular interest will be the higher frequencies of 20 and 30 GHz, where even light precipitation can cause significant attenuation. The paper presents some early comparisons between radar estimates of attenuation along an actual satellite path, and direct measurements, both at 30 GHz. There are two general aims. One is to assess the ability of the Chilbolton radar to predict attenuation at this frequency, and the second is to identify any limitations to the present experimental configuration