Analisi del posizionamento GNSS in tempo reale mediante reti RTK: il caso studio della Regione del Veneto

In this project, we aim to understand the accuracy of GNSS positioning given by different RTK networks, namely the Veneto GPS network, the Leica network (HxGN SmartNet), the Marussi network (Friuli-Venezia Giulia), and the TPOS (Trentino) network. For this purpose, the real-time differential corrections for elevations and geographic coordinates obtained utilizing these four networks are compared among themselves and also with the coordinates achieved using the relative positioning technique, which provides positioning with a very high level of precision. Among the four different networks, the Leica network is a national network and the other three networks are regional and all of them are the networks of continuous GNSS stations. The field surveys were carried out in two different test sites located in Padua and Longarone due to distances from regional networks and the positioning was performed at two observation points in each site. The differential corrections were achieved from the four networks using two antennas connected with two receivers and the corrections from each network were acquired within just five minutes, while the relative positioning performed using two receivers required a three-hour session in each site. These elevations and coordinates were determined using different spatial reference systems and UTM zones for comparison and finding the most accurate result. Furthermore, the results obtained using differential and relative positioning techniques were also compared with positioning obtained using classical topographic methods, which are: geometric leveling from the middle and total station survey, to observe whether the GNSS positioning determined using these different methods is comparable. The classical topographic method yields positioning results with the highest precision and thus they were considered to be the correct value. The difference in elevations between each of the two points and the 2D distance from the difference in the coordinates were calculated for implementing the comparison. It was found that the static or relative positioning method provided the most accurate results, which are very close to the positioning obtained through the classical topographic survey, while the differential positioning computed by different RTK networks also provided positioning with high level of precision, in the order of mm, and varied depending on their distance from the test site and other relevant factors.