A new noise reduction method for airborne gravity gradient data
1 Department of Geosciences, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 1, 24118, Kiel, Germany.
2 Astronomical Institute of the Czech Academy of Sciences, Fricova 298, 251 65 Ondřejov, Czech Republic.
3 Research Institute of Geodesy, Cartography and Topography, Ustecka 98, 250 66 Zdiby, Czech Republic.
4 Corresponding author. Email: jirigalatu@geophysik.uni-kiel.de
Exploration Geophysics 47(4) 296-301 https://doi.org/10.1071/EG15125
Submitted: 5 December 2015 Accepted: 14 August 2016 Published: 20 September 2016
Abstract
Airborne gravity gradient (AGG) measurements offer an increased resolution and accuracy compared to terrestrial measurements. But interpretation and processing of AGG data are often challenging as levelling errors and survey noise affect the data, and these effects are not easily recognised in the gradient components. We adopted the classic method of upward continuation in the noise reduction using the noise level estimates by the AGG system. By iteratively projecting the survey data to a lower level and upward continuing the data back to the survey height, parts of the high-frequency signal are suppressed. The filter, which is defined by this approach, is directly dependent on the noise level of the AGG data, the maximum number of iterations and the iterative step. We demonstrate the method by applying it to both synthetic data and real AGG data over Karasjok, Norway, and compare the results to the directional filtering method. The results show that the iterative filter can effectively reduce high-frequency noise in the data.
Key words: airborne gravity, filtering, noise.
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