PROPAGATION RESEARCH IN EUROPE USING THE OLYMPUS SATELLITE

Since the inception of commercial satellite communications, the predic tion of propagation impairments has been seen as a key element in the design of ground stations. In the last decade, satellite communication systems started to migrate from trunk telephony using large groundsta tions towards flexible video, data, and voice communications employing very small aperture terminals (VSAT's) at frequencies between 11 and 30 GHz. This led to new challenges for the propagation prediction mode ls because of the increased level of propagation impairments encounter ed above 10 GHz. In Europe, several successful collaborative ventures in wave propagation research have been undertaken in the past. The lau nch of the European Space Agency's (ESA) large telecommunications sate llite OLYMPUS in the summer of 1989 offered a unique opportunity to st udy the effects of the atmosphere on satellite communication links at Ku-band (14/12 GHz) and Ka-band (30/20 GHz). The community of OLYMPUS Propagation Experimenters (OPEX) operates experiments at more than 50 locations covering all of Western Europe with its different climatic r egions. The paper introduces the European propagation research scenari o, summarizes the major features of the current OLYMPUS campaign, disc usses the significance of the first results obtained and gives an outl ook on new activities.