An Adaptive Calibration and Beamforming Technique for a GEO Satellite Data Relay

High throughput data links from low earth orbit (LEO) satellites through a geostationary orbit (GEO) satellite data relay have been proposed to increase the available contact times to ground stations. Exact antenna beam pointing and tracking of moving targets are thereby key requirements for the relay satellite. In this work we propose an adaptive calibration and beamforming methodology based on least mean squares (LMS) which is suitable for a GEO data relais. The target System consists of the combination of a high gain reflector fed by a digitally steerable patch antenna array. The proposed method is first presented by numerical co-simulation of the antenna and the calibration algorithm. The results are then validated in an outdoor experimental setup with all digital signal processing implemented in a field-programmable gate array (FPGA). We demonstrate the tracking ability and pointing performance of the digitally enhanced reflector antenna with gain fluctuations smaller than 3 dB over a field of view of 2.9°. The demonstrated performance shows that the digitally enhanced reflector antenna is a suitable candidate for long distance space communications