The Italian Space Agency activities in radio occultation techniques

The Italian Space Agency (ASI) is very active in the field of Atmospheric Sounding by using the GNSS Radio Occultation Technique since several years. The main activities in this field are essentially : · the development and the manufacturing of a Proto Flight Model of the first GNSS Receiver for Geodetic application: Lagrange, installed on the Argentinean SAC-C satellite. This program was co-funded with the Italian Company Laben. · the development and the manufacturing of the Proto Flight Model of a GNSS Receiver for Radio Occultation called Lagrange RO . The activities of the Phase C/D of this instrument have been assigned to an industrial team composed by Laben (as prime contractor and with the responsibility of the receiver and the full payload) and to Alenia Spazio (responsible of the Radio Occultation Antennas). ASI plans to embark this payload on the Argentinian SAOCOM or SAC D satellite. The payload will be delivered to ASI for the first half of the 2004. In same time ASI is promoting internal and external scientific activities in the field. Concerning the internal activities ASI is developing a new approach for the retrieval of water vapour content without the need of external information ( namely ECMWF model or NCEP re-analysis). At this purposes some profiles and validation results will be presented.