000196032 001__ 196032
000196032 003__ CZ-ZdVUG
000196032 005__ 20201109113356.0
000196032 041__ $$aeng
000196032 040__ $$aABC039$$bcze
000196032 1001_ $$aPálinkáš, Vojtěch
000196032 24510 $$aFFT swept filtering: a bias-free method for processing fringe signals in absolute gravimeters
000196032 300__ $$a9 stran
000196032 5203_ $$aAbsolute gravimeters, based on laser interferometry, are widely used for many applications in geoscience and metrology. Although currently the most accurate FG5 and FG5X gravimeters declare standard uncertainties at the level of 2-3 µGal, their inherent systematic errors affect the gravity reference determined by international key comparisons based predominately on the use of FG5-type instruments. The measurement results for FG5-215 and FG5X-251 clearly showed that the measured g-values depend on the size of the fringe signal and that this effect might be approximated by a linear regression with a slope of up to 0.030 µGal/mV. However, these empirical results do not enable one to identify the source of the effect or to determine a reasonable reference fringe level for correcting g-values in an absolute sense. Therefore, both gravimeters were equipped with new measuring systems (according to Křen et al. 2016 applied for FG5), running in parallel with the original systems. The new systems use an analogue-to-digital converter HS5 to digitize the fringe signal and a new method of fringe signal analysis based on FFT swept bandpass filtering. We demonstrate that the source of the fringe size effect is connected to a distortion of the fringe signal due to the electronic components used in the FG5(X) gravimeters. To obtain a bias-free g-value, the FFT swept method should be applied for the determination of zero-crossings. A comparison of g-values obtained from the new and the original systems clearly shows that the original system might be biased by approximately 3-5 µGal due to improperly distorted fringe signal processing.
000196032 655_4 $$ačlánek v odborném periodiku
000196032 7001_ $$aVaľko, Miloš
000196032 7730_ $$92019$$dBerlin:Springer-Verlag,2019.$$g93. (2), s.219-227$$tJournal of Geodesy$$x0949-7714
000196032 8564_ $$uhttps://link.springer.com/article/10.1007/s00190-018-1154-y
000196032 85642 $$ahttps://www.rvvi.cz/riv?s=rozsirene-vyhledavani&ss=detail&n=0&h=RIV%2F00025615%3A_____%2F19%3AN0000002%21RIV19-GA0-00025615
000196032 910__ $$aABC039
000196032 980__ $$aclanky_vugtk
000196032 985__ $$apalinkas
000196032 985__ $$ariv
000196032 985__ $$autvar24
000196032 985__ $$avalko