Innovative data processing methods for gradient airborne geophysical data sets

FitzGerald, Desmond; Holstein, H.

doi:10.1190/1.2164762

Cited by 34 publications

(16 citation statements)

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“…Works have also demonstrated (FitzGerald and Holstein, 2006;Barnes et al, 2008;While et al, 2008) that proper use of the full tensor can increase the effective spatial resolution of a survey. Pajot et al (2008) describe a method in which differential equations are used to constrain the spatial behavior of measured tensor components, combining multiple components in a manner that denoises in a least-squares sense.…”

Section: Introductionmentioning

confidence: 94%

Processing gravity gradient data

Barnes

Lumley

2011

GEOPHYSICS

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As the demand for high-resolution gravity gradient data increases and surveys are undertaken over larger areas, new challenges for data processing have emerged. In the case of full-tensor gradiometry, the processor is faced with multiple derivative measurements of the gravity field with useful signal content down to a few hundred meters' wavelength. Ideally, all measurement data should be processed together in a joint scheme to exploit the fact that all components derive from a common source. We have investigated two methods used in commercial practice to process airborne full-tensor gravity gradient data; the methods result in enhanced, noise-reduced estimates of the tensor. The first is based around Fourier operators that perform integration and differentiation in the spatial frequency domain. By transforming the tensor measurements to a common component, the data can be combined in a way that reduces noise. The second method is based on the equivalentsource technique, where all measurements are inverted into a single density distribution. This technique incorporates a model that accommodates low-order drift in the measurements, thereby making the inversion less susceptible to correlated time-domain noise. A leveling stage is therefore not required in processing. In our work, using data generated from a geologic model along with noise and survey patterns taken from a real survey, we have analyzed the difference between the processed data and the known signal to show that, when considering the G zz component, the modified equivalent-source processing method can reduce the noise level by a factor of 2.4. The technique has proven useful for processing data from airborne gradiometer surveys over mountainous terrain where the flight lines tend to be flown at vastly differing heights.

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Section: Introductionmentioning

confidence: 94%

Processing gravity gradient data

Barnes

Lumley

2011

GEOPHYSICS

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“…Gravity gradient formulae for a 2D target with polygonal cross-section were derived by Jia and Meng (2009) and Jia and Wu (2011). Here the formulae have been "tensorized" (FitzGerald 2006) and specialized to the case of a semiinfinite 2D target (Holstein et al 2009). Txx and Txz gradient measures carry all the fault body characteristics.…”

Section: New Ftg Algorithmmentioning

confidence: 99%

Structural geology observations derived from full tensor gravity gradiometry over rift systems

Fitzgerald¹,

Holstein²

2014

SEG Technical Program Expanded Abstracts 2014

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“…Such magnetometers, using superconducting properties, present some difficulties, in particular the complex logistics for cryogens and associated systems. Also, the compensation of the magnetic effect of the airplane remains a problem (Hardwick 1984b; Fitzgerald and Holstein 2006) and it cannot be orientated precisely in an Earth's coordinate system. These difficulties of implementation reduce the progression of this equipment.…”

Section: Magnetic Gradiometry and Tensor Measurementsmentioning

confidence: 99%

Scalar, vector, tensor magnetic anomalies: measurement or computation?

Munschy

Fleury

2011

Geophysical Prospecting

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A B S T R A C TMagnetic surveys for geophysical interpretation will most usefully furnish estimates of the three components of the magnetic field vector. We review methods for obtaining this information based on scalar and tensor magnetic field measurements and point out the advantages of fluxgate vector measurements. Fluxgate vector magnetometers can be powerful instruments in magnetic mapping. The main problems in using fluxgate magnetometers arise from calibration errors and drift but these can be overcome using a quick and simple method of calibration. This method also has the advantage of compensating permanent and induced magnetic fields generated by the airplane. This is illustrated by a new aeromagnetic survey flown in the Vosges area (France). Measurement accuracy is shown to be similar to that obtained with scalar magnetometers. We take advantage of this accuracy to calculate in the Fourier domain other magnetic functions from the total-field anomaly, in particular, the magnetic gradient tensor is obtained without using any superconducting quantum devices. A similar approach is used to introduce a new magnetic anomaly tensor that is the equivalent of the pseudo-gravity tensor. Maps presented in the last sections serve as an example to illustrate the various functions, the goal of the paper being to obtain magnetic vector data from the observations without first postulating the detailed nature of the sources.

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Innovative data processing methods for gradient airborne geophysical data sets

Cited by 34 publications

References 0 publications

Processing gravity gradient data

Processing gravity gradient data

Structural geology observations derived from full tensor gravity gradiometry over rift systems

Scalar, vector, tensor magnetic anomalies: measurement or computation?

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