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International Journal of Geophysics
Volume 2012 (2012), Article ID 741729, 11 pages
http://dx.doi.org/10.1155/2012/741729
Research Article

On the Potential of Least Squares Response Method for the Calibration of Superconducting Gravimeters

1Geomatics Division, Faculty of Engineering & the Built Environment, University of Cape Town, Cape Town 7700, South Africa
2Department of Earth and Space Science and Engineering, York University, Toronto, ON, Canada M3J 1P3
3Department of Civil Engineering, Ryerson University, Toronto, ON, Canada M5B 2K3

Received 9 March 2012; Accepted 10 May 2012

Academic Editor: Umberto Riccardi

Copyright © 2012 Mahmoud Abd El-Gelil et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

One of the most important operating procedures after the installation of a superconducting gravimeter (SG) is its calibration. The calibration process can identify and evaluate possible time variability in the scale factor and in the hardware anti-aliasing filter response. The SG installed in Cantley, Canada is calibrated using two absolute gravimeters and the data are analysed in the time and frequency domains to estimate the SG scale factor. In the time domain, we use the weighted linear regression method whereas in the frequency domain we use the least squares response method. Rigorous statistical procedures are applied to define data disturbances, outliers, and realistic data noise levels. Using data from JILA-2 and FG5-236 separately, the scale factor is estimated in the time and frequency domains as μGal/V and μGal/V, respectively. The relative accuracy in the time domain is 0.015%. We cannot identify any significant periodicity in the scale factor. The hardware anti-aliasing filter response is tested by injecting known waves into the control electronics of the system. Results show that the anti-aliasing filter response is stable and conforms to the global geodynamics project standards.