The Peer review has evaluated this group as Excellent
The Geodesy area has been continuously present in the Department and it is actively involved in most of the relevant research fields of the geodetic sciences. Basic theoretical and numerical problems in mathematical and physical geodesy have been studied. Also, GPS surveying methods have been widely investigated from a methodological point of view and applications, ranging from RTK to geodetic monitoring of seismic faults, have been realized. Several international co-operations were established with the major geodetic research centers. Furthermore, the International Geoid Service (IGeS), an official IAG Center, has been established at DIIAR and it is actively operating in the field of geoid estimation. The research activities can be grouped and detailed according to the following main areas: - Mathematical geodesy. Theoretical researches on functional properties of (linear and non-linear) BVP’s for the Laplace operator are actively continuing; recent is a very general theorem on the Universal Solvability of classical BVP’s in suitable spaces of Hyperdistributions. In addition, suitable theoretical tools have been developed to analyze stochastic BVP’s in spaces of generalized random harmonic fields. More recently the fundamental problem of the stochastic techniques for the approximation of the gravity field has received a new light from its interpretation in terms of Malliavin calculus, as applied to this approximation problem in a Bayesian context. Furthermore, a new result has been obtained showing how to generalize the Kriging theory to the problem of a gravimetric geoid estimation. - Physical geodesy. The definition of a high precision geoid is nowadays one of the most relevant tasks in Geodesy. A precise geoid estimate, in combination with satellite altimetry data, can give valuable information on ocean circulation and it is commonly used to get orthometric heights from GPS observations. The method for computing a high precision geoid, the so called “remove-restore” technique, has been critically revised in order to get a reliable estimation procedure. The aim of this research is to improve the geoid undulation estimate in order to reach the one centimeter precision in dense gravity coverage areas. The main outcome of these investigations is the last estimate of the Italian geoid, computed at DIIAR in 2005, which is considered as the official geoid estimate by IGM (Istituto Geografico Militare), the Italian national surveying and mapping agency. Another key research in physical geodesy is related to the analysis of the gradiometric GOCE mission data. The ESA project GOCE (Gravity field and steady-state Ocean Circulation Explorer) is scheduled for launch in December 2007. GOCE will be the first satellite gradiometry mission for the exploration of the Earth gravity field and has been specifically designed to determine the stationary part of the field (geoid and gravity anomalies) with high spatial resolution and to very high accuracy. Such an advance in the knowledge of the Earth gravity field and its geoid will help to develop a much deeper understanding on how the Earth interior system works. The DIIAR research team has proposed an original method for the treatment of satellite gradiometry data, the so called space-wise approach. This method has been recognized by ESA as one of the official GOCE data reduction scheme for the production of a GOCE Earth gravity field model. GPS surveying. GPS technique is routinely used in modern surveying and it can have many different applications with sharply different precisions (from some millimeters to some meters). At present, the main focus is on networks of GPS permanent stations both for real time positioning and for geodynamical investigations. In this particular area, DIIAR has cooperated with Regione Lombardia to set up a network of eighteen GPS permanent stations allowing real time applications. This GPS network, the first one in Italy, is fully operational thus providing support to GPS users. Furthermore, the analysis of GPS permanent stations data for geodynamic investigations has been carried out in the framework of the EU ALPS-GPSQUAKENET project which aims at defining the crust deformation in the whole Alpine region. Data analysis has been performed according to the highest standards and following an original method which improves the standard technique by taking into account time correlations in the daily solution time series. Also, non-permanent GPS networks have been established and surveyed yearly in three active fault areas: the Colfiorito area (Umbria), the Pollino area (Calabria) and the Gemona area (Friuli). Improvements in data acquisition and data processing led to highly reliable results which have been used in the refinements of fault geophysical models.