No abstract

Arrays composed of high-gain reflector antennas are used for radio-astronomical purposes and, more recently, are proposed as ground station for deep space communications. This latter application requires a precise knowledge of the degradation that phase, amplitude and pointing fluctuations impose on the capability of the array to combine coherently the signal received or transmitted from each antenna. In this study, an analytical model for the fluctuation of each parameter (phase, amplitude and pointing) is derived and it is used to predict the efficiency of an array composed of an arbitrary number of high-gain reflector antennas. The analytical models are verified by numerical simulations and applied to an array layout currently proposed as possible future ground stations for the European Space Agency.

Multi-satellite missions, such as the next generation of METEOSAT geostationary satellites, require a ground station able to support an arbitrary number of satellites that can fly wherever within a pre-determined sky region, called control box. The use of high frequencies, around 26 GHz, imposes on the ground station high antenna gains to compensate for the noise temperature collected at those frequencies to obtain the specified G/T. Regardless of the narrow beamwidths that emerged from the adoption of high antenna gains, it is also required to operate with fixed (i.e. without any kind of tracking) antennas. This paper shows how all these specifications drive a new type of ground station with respect to current solutions. The proposed architecture is based on a multi-reflector system able to provide a set of interleaved beams, which generates an almost uniform coverage of the control box. The architecture is analyzed and designed, optimizing all the main antenna parameters, and presenting the analytical results.