Summary: During the seminar the main research lines of the Aeronomy and Radiopropagation Laboratory will be discussed. In addition, the major ICTP programmes with which the laboratory is concered will be briefly reviewed.
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(*) Prof. Sandro M. Radicella is the Head of the Aeronomy and Radiopropagation Laboratory (ARPL) of the Abdus Salam International Centre for Theoretical Physics. He has published more than 130 papers in the fields of aeronomy and radiocommunications.

The most important achievement of his recent scientific production is the development of models of vertical distribution of electronic density in the ionosphere in collaboration with colleagues from the ARPL and of the University of Graz, Austria.

The Global Positioning System, GPS, is a set of 24 well-spaced satellites that orbit the Earth and make it possible for people with ground receivers to pinpoint their geographic location. This radio navigation system allows land, sea, and airborne users to determine their exact location, velocity, and time 24 hours a day, in all weather conditions, anywhere in the world. One of the models of Professor Radicella and collaborators (of vertical distribution of electronic density in the ionosphere) is being used by ESA, the European Space Agency, in areas related to the new GALILEO satellite system.

Besides, at the administration level, he has systematically organized a series of Colleges, Schools and Workshops, for participants mainly from developing countries, in the fields of Ionospheric Physics, Radiocommunications and Information and Communication Technology that he directs at the ICTP since 1989.

Significantly he has been awarded in 2001 with the Doctor Honoris Causa degree from the University of Bucharest, Romania, and in 2005 with the Doctor of Science degree Honoris Causa from the Obafemi Awolowo University in Ile-Ife, Nigeria.

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