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Journal of Geodesy

, Volume 90, Issue 1, pp 91–99 | Cite as

Optimized strategy for the calibration of superconducting gravimeters at the one per mille level

  • Michel Van Camp
  • Bruno Meurers
  • Olivier de Viron
  • Thomas Forbriger
Short Note

Abstract

This paper reports on different sources of errors that occur in the calibration process of a superconducting gravimeter (SG), determined by comparison with a ballistic absolute gravimeter (AG); some of them have never been discussed in the literature. We then provide methods to mitigate the impact of those errors, to achieve a robust calibration estimate at the Open image in new window level. We demonstrate that a standard deviation at the level of Open image in new window can be reached within 48 h by measuring at spring tides and by increasing the AG sampling rate. This is much shorter than what is classically reported in previous empirical studies. Measuring more than 5 days around a tidal extreme does not improve the precision in the calibration factor significantly, as the variation in the error as a function of \(1/\sqrt{N} \) does not apply, considering the decrease in signal amplitude due to the tidal modulation. However, we investigate the precision improvement up to 120 days, which can be useful if an AG is run continuously: at mid-latitude it would require 21 days to ensure a calibration factor at the Open image in new window level with a 99.7 % confidence interval. We also show that restricting the AG measurement periods to tidal extrema can reduce instrument demand, while this does not affect the precision on the calibration factor significantly. Then, we quantify the effect of high microseismic noise causing aliasing in the AG time series. We eventually discuss the attenuation bias that might be induced by noisy time series of the SG. When experiments are performed at the Open image in new window level, 7 are needed to ensure that the error in the calibration estimate will be at the 1 per mille level with a 99 % confidence.

Keywords

Calibration Superconducting gravimeter Absolute gravimeter  Earth tide 

Notes

Acknowledgments

The work of OdV is financially supported by the Institut Universitaire de France. We thank the editor Roland Klees and three anonymous reviewers for their fruitful comments.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Michel Van Camp
    • 1
  • Bruno Meurers
    • 2
  • Olivier de Viron
    • 3
  • Thomas Forbriger
    • 4
    • 5
  1. 1.Royal Observatory of BelgiumUccleBelgium
  2. 2.Department of Meteorology and GeophysicsUniversity of ViennaViennaAustria
  3. 3.Université de La Rochelle-CNRS UMR 7266, Littoral Environnement et Sociétés (LIENSs)La RochelleFrance
  4. 4.Black Forest Observatory (BFO)WolfachGermany
  5. 5.Geophysical InstituteKarlsruhe Institute of Technology (KIT)KarlsruheGermany

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