PMD IVS Analysis Center

The main activities carried out at the PMD (Politecnico di Milano DIIAR) IVS Analysis Center during 2012 are briefly higlighted, and future plans for 2013 are sketched out. We principally continued to process European VLBI sessions using different approaches to evaluate possible differences due to various processing choices. Then VLBI solutions were also compared to the GPS ones as well as the ones calculated at co-located sites. Concerning the observational aspect, several tests were performed to identify the most suitable method to achieve the highest possible accuracy in the determination of GNSS (GLOBAL NAVIGATION SATELLITE SYSTEM) satellite positions using the VLBI technique. 1. General Information The Department DIIAR (Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture viarie e Rilevamento) belongs to the Technical University of Milan (Politecnico di Milano). The ‘Rilevamento’ research unit deals with various areas of research that concern, e.g., classical topography and photogrammetry surveying, numeric cartography, GIS (Geographic Information Systems) data processing, remote sensing, GNSS static and real time positioning, and mathematical and physical geodesy (space geodesy included). In this framework, the PMD IVS AC and the IAG (International Association of Geodesy) Service: IGES (International Geoid Service) are hosted and operated. DIIAR continues to support all office supplies, hardware, and personnel necessary to manage the PMD IVS AC since its establishment in October 2010 [1]. Part of the work here described was developed also with the support of MIUR (Ministry of Education, University, and Research) under the framework of a project with considerable national interest. 2. Current Status and Activities All the European sessions available since 1990 through the end of 2011 have been processed under the same modeling conditions and analogous parameterizations. To calculate solutions, we used the VieVS (Vienna VLBI Software) software [2] developed by the members of the VLBI group of the Institute of Geodesy and Geophysics (IGG) at the Vienna University of Technology (TU Wien). Among the different approaches used to process European sessions, we report on the investigations made on seven VLBI stations that had longer historical data series and were co-located with GPS stations. The period used in this preliminary study starts in 1993 and ends in 2007. European site coordinates and baseline lengths (with respective variance-covariance matrices), have been estimated to study their temporal evolution. The adjustments were performed using the single session approach. The baseline lengths, used to infer European crustal deformations, were calculated with respect to the Wettzell station due to its stable position in the European network and its barycentric location with respect to the other six stations selected for the study (Onsala, Ny-Ålesund, Madrid, Medicina, Matera, and Noto). The results were compared with those calculated in another previously performed study [3]. 302 IVS 2012 Annual Report https://ntrs.nasa.gov/search.jsp?R=20150003917 2018-04-10T05:50:46+00:00Z