The propagation and telecom experiments of the Alphasat Aldo payload (TDP5 Q/V band experiment)

The utilization of millimetric waves in satellite communications requires the use of advanced transmission techniques known as Propagation Impairments Mitigation Techniques (PIMT) to counteract severe atmospheric phenomena without excessive power expenditures. Among these PIMTs we remind Adaptive Code Modulation (ACM), reconfigurable antenna pattern, site diversity, up/down link power control and others. The possibility to exploit profitably this concept is based on the knowledge coming from the propagation science, i.e. on accurate models for the space- and time-distribution of impairments such as rain attenuation and to allow their experimental validation through measurements. The TDP5 Q/V Band Propagation Payload, which has been renamed as Alphasat Aldo payload to the memory of Prof. Aldo Paraboni, who conceived and greatly contributed to its realization, will allow in the near future further propagation and telecom measurements across Europe. The mission will allow a direct assessment of the advantages obtainable from PIMTs like the ACM or reconfigurable on-board antenna. The payload has been supported by the Italian Space Agency (ASI) as in-kind contribution to the Alphasat project which is executed by the European Space Agency (ESA) in the framework of the ARTES 8 Telecom programme. Alphasat will be launched in 2013. The Aldo payload will permit simultaneous measurements of attenuation and depolarisation at 20 and 40 GHz during a long period (some years) all over Europe. In addition the Aldo payload will enable telecom Q/V experiments at the stations located within the 3 narrow spot beams covering Austria, North and South Italy. As for the ground segment, ASI assumed directly the commitment to realize the deployment and realization of the Earth terminals in Italy with the support of Politecnico di Milano and Univ. Tor Vergata as Principal Investigators for the propagation and telecommunication experiments, respectively. One of these terminals will be placed at the experimental station of Spino d'Adda (near Milan, North of Italy); another one will be installed in Tito Scalo (South of Italy). A third Earth Terminal for the telecom experiment is being developed by Joanneum Research (in the framework of an ESA ARTES 8 activity with the support of the Austrian Aeronautics and Space Agency) and it will be installed in Graz, Austria. As well, in order to enlarge the significance of this experiment, the development of additional propagation ground terminals for Alphasat has been assigned by ESA within the ARTES-5 programme for Telecom technology development to Joanneum Research and Graz University of Technology. In the frame of this contract a propagation terminal will be placed in Graz to perform joint measurements with the Telecom station. In this contribution the status and the planning of the Alphasat TDP5 experiments will be presented with particular regard to the ground segment and the planning for scientific activities.