Reception of wideband signals from geostationary collocated satellites with antenna arrays

Reception of satellites in Ka-band is complicated because of narrow beams of ground station antennas. Narrower beams bring about higher pointing losses and the impossibility to capture multiple geostationary collocated satellites with the same aperture. One way to solve both problems is by using arrays of small dishes. Besides, if rain diversity is used, several ground stations must be deployed in sites separated by several tens of kilometres. The signals received by these stations could be combined in a central site to gain additional margin in the link budget. This study shows the processing scheme necessary to combine the signals both at the remote sites and the central site. It is based on a subband beamformer with subband delay compensation in order to be able to cope with the delay difference between the satellites. In order to estimate the phase and delay offsets between far away ground stations, an algorithm that works with the subband signals is proposed. Theoretical and simulation results validate the proposed approach.