The backbone of this integration is the existing global ground network, based on the geodetic space techniques: very long baseline interferometry, satellite laser ranging, global navigation satellite systems and Doppler orbitography and radiopositioning integrated by satellite. These techniques have to operate as one global entity and in one global reference frame. The global reference frame in the GGOS is a realization of the International Terrestrial Reference System (ITRS). The ITRS is a world spatial reference system co-rotating with the Earth in its diurnal motion in the space. The IAG Subcommision for the European Reference Frame (EUREF) in 1991 recommended that the terrestrial reference system for Europe should be coincident with ITRS at the epoch tĠ = 1989.0 and fixed to the stable part of the Eurasian Plate. It was named the European Terrestrial Reference System 89 (ETRS89). On the 2nd of June 2008, the Head Office of Geodesy and Cartography in Poland commenced operating the ASG-EUPOS multifunctional precise satellite positioning system. The ASG-EUPOS network defines the European Terrestrial Reference System ETRS89 in Poland. A close connection between the ASG-EUPOS stations and 15 out of 18 Polish EUREF permanent network stations controls the realization of the ETRS89 on Polish territory. This paper is a review of the global ITRS, as well as a regional and a national geodetic reference systems ETRS89. This study implemented a stable Regional Reference Frame in Shanghai, East China (called SHRRF), using seven years of continuous GNSS observations from the Shanghai Continuously Operating Reference System stations (SHCORS) to examine reclaimed coast–land subsidence. A well−distributed core station network suitable for regional applications was derived. The instantaneous station coordinates and seven frame parameters (translations, rotations, and scale) were estimated at each epoch through minimum constraint during the process of aligning SHRRF to the International Terrestrial Reference Frame (ITRF14). ![]() The average root mean square error (RMSE) of all stations under SHRRF was within 1.5 mm horizontally and 5 mm vertically for most epochs. Simultaneously, compared with the ITRF14 solutions, the average RMSE for each site at all epochs was reduced by ~30% horizontally and ~10% vertically. A temporal consolidation settlement model of the reclaimed soil under self−weight was established by combining a geotechnical−derived model with high precision permanent GNSS vertical solutions under SHRRF. The model indicates that ~50% of settlements occurred within 3.6 years, with the whole subsidence time being 46 years. SHRRF provides a precise regional reference frame for use in many East China geophysical applications besides reclaimed coast–land settlement including hydrologic loading, microplate motions, and critical structure deformation monitoring. Brausser and Solomon (2005) indicaron que la presencia de NOX = NO + NO2 y compuestos nitrogenados relacionados como el ácido nítrico (HNO3) en la atmósfera media, resultan de la oxidación del óxido nitroso (N2O) y de la ionización del nitrógeno molecular (N2) por partículas solares de alta energía. Además, gran parte de la energía transportada por los protones solares podría afectar la atmósfera media dando lugar a interacciones atmosféricas que incrementarían la producción de constituyentes de NOx, lo que puede provocar variaciones en el contenido de ozono Jackman, 1991 Jackman et al., 1995 2014. Las partículas solares energéticas (protones, con energías entre 1 MeV y unos pocos cientos de MeV y electrones, con energías entre decenas de keV y unos pocos MeV) son una fuente importante de ionización para la mesosfera y la estratosfera superior (Turunen et al., 2009 Sepällä et al, 2014). Durante las SPE, la precipitación de partículas en la atmósfera puede producir una disminución del ozono con un aumento de NO2 en latitudes 45 ° en la estratosfera superior (Sepällä, 2004(Sepällä, 2006López-Puertas et al., 2005). The study introduces an efficient methodology to perform the transformations between station coordinate and velocity solutions where either minimum or redundant datum constraints have been imposed employing the estimated state vector and the covariance matrix thereof. The analytical methodology presented herein facilitates the datum alignment of largenetwork solutions, especially for the GNSS technique.
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