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Boccolari, M.
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- PublicationOpen AccessDetection of meteorological inconsistencies by GPS(2003)
; ; ; ; ; ;Balestri, L.; Dipartimento Ingegneria dei Materiali e dell' Ambiente (Osservatorio Geofisico), Università degli Studi di Modena e Reggio Emilia, Modena, Italy ;Boccolari, M.; Dipartimento Ingegneria dei Materiali e dell' Ambiente (Osservatorio Geofisico), Università degli Studi di Modena e Reggio Emilia, Modena, Italy ;Fazlagic, S.; Dipartimento Ingegneria dei Materiali e dell' Ambiente (Osservatorio Geofisico), Università degli Studi di Modena e Reggio Emilia, Modena, Italy ;Pugnaghi, S.; Dipartimento Ingegneria dei Materiali e dell' Ambiente (Osservatorio Geofisico), Università degli Studi di Modena e Reggio Emilia, Modena, Italy ;Santangelo, R.; Dipartimento Ingegneria dei Materiali e dell' Ambiente (Osservatorio Geofisico), Università degli Studi di Modena e Reggio Emilia, Modena, Italy; ; ; ; GPS observations, distances from satellites to receivers and meteorological conditions in neutral atmosphere are known to obey a constraint, which provides a residual or in other words a quality index. A method is discussed which provides a residual epoch by epoch in near real time. In general, distribution of residuals during several consecutive epochs belonging to the same satellites, allows estimates of a mean and a standard deviation of mean. Under normal meteorological conditions distribution of residuals appears to be consistent with zero mean as expected. However, consecutive residuals sometimes appear to have a mean different from zero by more than three standard deviations of mean. Such signifi cant consecutive epochs provide a warning of existing inconsistencies among GPS observations, distances from satellites to receivers as obtained by orbital information, meteorological conditions above receivers (as obtained by ground measurements or by extrapolation of meteorological analysis). A procedure has been set up which warns about these inconsistencies in near real time.130 237 - PublicationOpen AccessGPS Zenith Total Delays and Precipitable Water in comparison with special meteorological observations in Verona (Italy)during MAP-SOP(2002)
; ; ; ; ; ; ; ; ;Boccolari, M.; DIMA -Osservatorio Geofisico (OGMO),Università di Modena e Reggio Emilia,Italy ;Fazlagic, S.; DIMA -Osservatorio Geofisico (OGMO),Università di Modena e Reggio Emilia,Italy ;Frontero, P.; ARPAV Department of Verona Province,Verona,Italy ;Lombroso, L.; DIMA -Osservatorio Geofisico (OGMO),Università di Modena e Reggio Emilia,Italy ;Pugnaghi, S.; DIMA -Osservatorio Geofisico (OGMO),Università di Modena e Reggio Emilia,Italy ;Santangelo, R.; DIMA -Osservatorio Geofisico (OGMO),Università di Modena e Reggio Emilia,Italy ;Corradini, S.; DIMA -Osservatorio Geofisico (OGMO),Università di Modena e Reggio Emilia,Italy ;Teggi, S.; DIMEC -Università di Modena e Reggio Emilia,Italy; ; ; ; ; ; ; Continuous meteorological examination of the Pre-Alpine zones in Northern Italy (Po Valley)is important for determination of atmospheric water cycles connected with floods and rainfalls.During a special meteorological observing period (MAP-SOP),radiosounding and other measurements were made in the site of Verona (Italy). This paper deals with Zenith Total Delay (ZTD)and Precipitable Water (PW)comparisons obtained by GPS, radiosounding and other meteorological measurements.PW and ZTD from ground-based GPS data in comparisonwith classical techniques (e.g.,WVR,radiosounding)from recent literature present an accurate tool for use in meteorology applications (e.g.,assimilation in Numerical Weather Prediction (NWP)models on short-range precipitation forecasts).Comparison of such ZTD for MAP-SOP showed a standard deviation of 16.1 mm and PW comparison showed a standard deviation of 2.7 mm,confirming the accuracy of GPS measurements for meteorology applications.In addition,PW data and its time variation are also matched with time series of meteorological situations.Those results indicate that changes in PW values could be connected to changes in air masses,i.e.to passages of both cold and warm fronts.There is also a correlation between precipitation, forthcoming increase and the following decrease of PW.A good agreement between oscillation of PW and precipitation and strong cyclonic activities is found.245 537 - PublicationOpen AccessGPS Coordinate Estimates by “a priori” Tropospheric Delays from NWP using Ultra-Rapid Orbits(2006-11-28T08:37:17Z)
; ; ; ;Boccolari, M.; DIMA, University of Modena and Reggio Emilia ;Fazlagic', S.; DIMA, University of Modena and Reggio Emilia ;Santangelo, R.; DIMA, University of Modena and Reggio Emilia; ; Comparisons of high accuracy GPS positioning estimates using scientific GPS software through three different processing strategies have been done. The two Italian baselines in a time period of 5 months during 2004 made a calculus data set. For high accuracy GPS differential positioning the employ of global tropospheric delay models can be replaced by the implementation of other techniques. The GPS coordinate repeatability when the tropospheric delay is calculated in near-real time (NRT) from a Numerical Weather Prediction (NWP) model, is experienced. For the NRT approach IGS Ultra-Rapid orbits instead of Precise orbits were used. Concerning coordinate repeatability, the NWP-based strategy with tropospheric error adjustment appeared as the more accurate (at the submillimetric level) with respect to a standard GPS strategy. Furthermore, several hundreds km long baselines demonstrated the standard deviation at the level of millimeters (from 4.2 to 7.6 mm). Practically, the NWP-based strategy offers the advantage of tropospheric delay estimations closer to realistic meteorological values. The application of a more accurate meteorology leads to the satisfactory coordinate estimations, and vice versa the well-defined GPS estimations of coordinates may serve as the additional meteorological parameters source.145 1158