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CoverNewton's Bulletin

Issue n. 3, January 2006   [pp. 50-60]

On the potential of wavelets for filtering and thresholding airborne gravity data

M. El-Habiby and M.G. Sideris

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Wavelets can be used in the decomposition and analysis of airborne gravity data. In this paper, multiresolution analysis is applied to de-noise gravity disturbance and different de-noising techniques are studied. The first objective is testing the usefulness of wavelets for analyzing and filtering airborne gravity data. The second one is a comparison between the usage of the wavelet transform and other well known low-pass filters. The gravity disturbances are filteredusing wavelet thresholding to remove the noise introduced by the dynamics of the aircraft. Two procedures have been tested. The first one is de-noising using minimax and universal techniques. The second one is a combination of wavelet thresholding and filtering at certainlevels. Comparison to independent reference data is performed in the area of interest to determine the external accuracy of this approach. Results from both cases and from the low-pass filter approach are compared.The results of testing different de-noising techniques show that the combination of thresholding and filtering can reach RMS values equal to 25 mGal in comparison to the results from the 90s low-pass filter.