The Italian North-South GPS Traverse for a "first order" Italian geoidal net *

Some time ago it was agreed to set up a European GPS Traverse from Troms6 (Norway) to Syracuse (Sicily), to improve the definition of the European geoid. An outline of the Italian portion of this Traverse is summarized here, with special reference to the sections from the Brenner Pass to Taranto - carried out in 1989 and for those from Taranto to Syracuse-Noto, recently completed. The observing procedures and results are reported here. A comparison with the results of the ITALGEO '90 geoid, and a tentative profile of the Italian geoid along the whole traverse are also sketched. Furthermore, a net of similar traverses, a "first order geoidal net" in Italy is proposed, in order to support the existing and new geoid determinations. In such a way a sub-decimetric accuracy in the Italian GPS derived orthometric heights may probably be achieved