Title: DC Gradiometers for Bomb Detection: Scalar Versus Vectorial
Authors: RIPKA PavelLEWIS ADAMKASPAR PETRVCELAK JAN
Citation: Sensor Letters vol. 5 no. 1 p. 1-5
Publisher: American Scientific Publishers
Publication Year: 2007
JRC N°: JRC35457
URI: http://publications.jrc.ec.europa.eu/repository/handle/JRC35457
Type: Contributions to Conferences
Abstract: Location of UXO (unexploded ordnance) using its DC magnetic signature requires precise gradiometers: resonant scalar and vectorial fluxgate sensors are used. The needed resolution is 1 nT in 50 000 nTEar th’s field. Scalar gradiometers are very stable, but in some positions the scalar gradient is very small and the target may be overlooked. The disadvantage of the double-sensor fluxgate vectorial gradiometer is its high sensitivity to angular mismatch. This may be partly suppressed by using a 3-axial gradiometer arrangement with 6 sensors, which also gives more information from one reading. We developed field calibration procedures for such an instrument which allow the correction of misalignments down to 0.05 deg. DC gradiometers are typically used for deep and large objects. We demonstrate that they are also able to find small cluster bomb submunitions and that they are less affected by metal scrap than existing eddy-current UXO detectors. The field shape from a small bomb strongly depends on local field inclination; the magnetically hard component is not negligible, so that the signature depends also on the magnetic history and orientation of the target.
JRC Institute:Institute for the Protection and Security of the Citizen

Files in This Item:
There are no files associated with this item.


Items in repository are protected by copyright, with all rights reserved, unless otherwise indicated.