Evaluating the Effects of Magnetic Susceptibility in UXO Discrimination Problems

Pasion, Leonard R.; Billings, Stephen; Oldenburg, Douglas W.

doi:10.4133/1.2927057

Cited by 17 publications

(27 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This distribution is shown as a function of frequency in Figure 3, and fits the measured susceptibility of soil samples from Kaho'olawe, Hawaii [25]. Other distributions may be needed for soils in other locales.…”

Section: Signalmentioning

confidence: 99%

“…where the diagonal components of ↔ M are from (25), H 0 (r) is the primary magnetic field at the UXO location r due to the transmitter coil calculated using (7), H rx (r) is the magnetic field at the UXO location due to a test current (taken to be unity) in the receiver coil I rx (also calculated using (7)), and it is assumed that the primary field is constant across the target. Since the ALLTEM uses two receiver coils in gradiometer configuration, the response is the difference between the two receiver signals,…”

Section: Signalmentioning

confidence: 99%

See 1 more Smart Citation

Combining Advances in Em Induction Instrumentation and Inversion Schemes for Uxo Characterization

Oden¹

2012

PIER B

View full text Add to dashboard Cite

Abstract-Several experimental time-domain EM induction instruments have recently been developed for unexploded ordnance (UXO) detection and characterization that use multiple transmitting and receiving coil combinations. One such system, the US Geological Survey's ALLTEM system, is unique in that it measures both the electrodynamic response (i.e., induced eddy currents) and the magneto-static response (i.e., induced magnetization). This allows target characterization based on the dyadic polarizability of both responses. This paper examines the numerical response of the ALLTEM instrument due to spheroidal, conductive, and permeable UXO targets; and to conductive and optionally viscous magnetic earth. An inversion scheme is presented for spheroidal targets that incorporates fully polarimetric measurements for both magneto-static and electro-dynamic excitations. The performance of the inversion algorithm is evaluated using both simulated and surveyed data. The results are examined as a function of the number of coil combinations, number of instrument locations, and uncertainty in sensor location and orientation. Results from the specific cases tested (prolate spheroids lying horizontally) show that 1) that collecting data from more than 12 sensor locations or from more than four coil combinations reduced the chances that inversion solutions would be from a local minimum, and 2) that uncertainties in position greater than 3 cm or in orientation greater than 10 degrees cause errors in the estimated spheroid principal lengths of greater than 100%. Soil conductivities less than 1 S/m contribute negligible interference to the target response, but viscous magnetic soils with permeabilities greater than 10 −6 MKS units do cause detrimental interference.

show abstract

Section: Signalmentioning

confidence: 99%

Section: Signalmentioning

confidence: 99%

Combining Advances in Em Induction Instrumentation and Inversion Schemes for Uxo Characterization

Oden¹

2012

PIER B

View full text Add to dashboard Cite

show abstract

“…A vertical dipole (or horizontal loop) transmitter produces an null half-space response in the horizontal component (Pasion et al, 2002a). Conversely, a horizontal dipole (or vertical loop) transmitter will produce a null response in the vertical direction.…”

Section: Differential Measurements Through Varying the Transmitter Fimentioning

confidence: 99%

“…The smaller conductivity is applicable to the soils on Kaho'alawe Island, Hawaii, while the second represents a soil with a very high conductivity. We use the same susceptibility model as Pasion et al (2002a) which was derived from soil measurements on Kaho'alawe Island, Hawaii (Figure 2.3).…”

Section: Modeling the Em Response Under Different Scenariosmentioning

confidence: 99%

UXO Target Detection and Discrimination with Electromagnetic Differential Illumination

Foley¹

2005

View full text Add to dashboard Cite

show abstract

“…Wavelet transforms decompose different components of a signal into different regions in the space-frequency domain and thereby allow one to separate them or extract a particular feature. Both continuous wavelet transform (CWT) based natural wavelets (e.g., Hornby et al, 1999;Haney and Li, 2002) and discrete wavelet transform (DWT) based on compactly supported orthonormal wavelets (e.g., Ridsdill-Smith and Dentith, 1999;Li and Oldenburg, 2003;Lyrio et al, 2004) have been used successfully in the processing and inversion of magnetic data in exploration geophysics. In the section of the report on filtering using wavelet transforms, we will present current research and results on application of the DWT for separating UXO and soil response in strong magnetic environments.…”

Section: Magnetic Data Processingmentioning

confidence: 99%

Improving UXO Detection and Discrimination in Magnetic Environments

Li¹,

Krahenbuhl²,

Meglich³

et al. 2010

View full text Add to dashboard Cite

Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. for improved modeling of geophysical data in these environments. Lastly, through our field work we have discovered that sites previously thought to be benign may exhibit weak viscous remanent magnetization. Thus the field activities from this project have broad implications for ongoing and future remediation efforts in similar environments within the continental US. 3On another research front, we have utilized the information gathered from our field and laboratories activities to develop robust forward modeling algorithms and material on filter analysis of TDEM data in the presence of magnetic geologic noise. For example, we present a method for simulating the background response of strong magnetic environments on EM data using correlated random numbers. We show how these simulated responses may prove viable for discrimination of UXO in these magnetic terrains.Finally, we demonstrate new sets of procedures for improved target detection and decreased false positives in strongly magnetic environments based on the magnetic method. This includes development and implementation of iterative Wiener and wavelet based filter approaches for separating the response of magnetic geology from those of UXO. In addition, we demonstrate successful implementation of a high-pass Butterworth filter originally applied during decorrugation of unleveled magnetic data for the same purpose.4

show abstract

Evaluating the Effects of Magnetic Susceptibility in UXO Discrimination Problems

Cited by 17 publications

References 7 publications

Combining Advances in Em Induction Instrumentation and Inversion Schemes for Uxo Characterization

Combining Advances in Em Induction Instrumentation and Inversion Schemes for Uxo Characterization

UXO Target Detection and Discrimination with Electromagnetic Differential Illumination

Improving UXO Detection and Discrimination in Magnetic Environments

Contact Info

Product

Resources

About