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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 11:53 |
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Conference: Bucharest University Faculty of Physics 2021 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Determining the seasonal signal and noise in different CORS GNSS Network from Romania
Authors:
Sorin Nistor 1, Norbert-Szabolcs Suba 1, Eduard Ilie Nastase 2, and Alexandra Muntean 2
*
Affiliation:
1 University of Oradea, Faculty of Construction, Cadastre and Architecture, Oradea, Romania,
2 National Institute for Earth Physics, Bucharest, Romania
E-mail
sonistor@uoradea.ro
Keywords:
GNSS time series; noise, seasonal signal, MLE
Abstract:
Daily coordinate time series from Global Navigation Satellite System (GNSS) exhibits important seasonal signals for horizontal and vertical component. These essential signals must be estimated because it plays a very important role in the final estimates, especially for site velocity. The seasonal signal experience mainly an annual and semi-annual period which can be modeled with a constant amplitude and phase-lag. The article is analyzing in terms of seasonality and noise 152 stations from 5 different Continuously Operating Reference Stations (CORS) that have GNSS stations in Romania. The importance of this study is twofold: the first one is given by the relevance of separating various geophysical signals which truthfully can reflect critical crustal deformation or the effect of different surface mass loadings, and second, is the compare relatively close stations which are part of two different CORS networks. Due to the fact that the underlying noise of the GNSS station is related to the seasonal signal, using Maximum Likelihood Estimation (MLE) we are able to estimate both seasonal signals, the type of noise and its amplitude for the Romanian GNSS CORS network. The results of the noise analysis show that at low frequencies we have spectral indices that varies between -2 and 0, which reveals that the dominant type of noise is flicker and random noise.
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