The objective of this activity was to define end-to-end on-board self-calibration techniques for payloads using advanced distributed elements as active/semi-active antennas and Multi Port Amplifiers, to identify architectural options for their implementation, to perform a trade-off between those options and to analyse their feasibility and performance. The calibration shall be performed avoiding telecommunication service interruption and minimizing the degradation in the Quality of Service.
The study has enlighten the trade-off between the need for avoiding service interruption and guaranteeing minimum degradation in Quality of Service (in terms of BER) as well as limiting TWTAs IBO variation and the need to achieve good amplitude & phase residual impairments between payload RF chains in order to meet the stringent requirements in terms of minimum antenna gain and beam isolation of next generation satellite missions.
The extensive analyses, simulations and measurements allowed to identify suitable calibration techniques and architectures meeting all the requirements with minimum complexity.
Use of a calibration system should result in following benefits:
Main advantages of an On-board Calibration include performance enhancement of any RF chain in any redundant configuration, for any operational point of the Payload whatever the operational traffic and in any temperature/ageing condition.
The basic idea of the proposed concept for the on-board calibration sub-system addressed in the study relies on a closed loop calibration consisting of four steps:
Project Plan has been composed of five major tasks:
The Project is COMPLETED.
Axes of further improvements have also been highlighted, mainly consisting in the need for developing calibration subsystem proof of concepts/engineering breadboards fully representative of the operational behaviour of the target calibration subsystem in closed loop (i.e., addressing both impairments estimation and correction) and under traffic conditions.