Electromagnetic cave-to-surface mapping system

Sogade, John; Vichabian, Yervant; Vandiver, Amy; Reppert, Philip M.; Coles, Darrell; Morgan, Frank Dale

doi:10.1109/tgrs.2003.819882

Cited by 24 publications

(14 citation statements)

References 11 publications

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“…Other geometric properties of the geo-location system may be inferred by measuring only the vertical component of the signal strength [2], approximating field derivatives by making multiple measurements at juxtaposed locations [1,3], or by taking ratios of signal strengths measured at widely separated locations [4,5]. Information about the receiver position can also be found by locating the position on the surface where there is a peak in the horizontal field component [6] or by taking ratios of field components [7].…”

Section: Introductionmentioning

confidence: 99%

A null-field method for estimating underground position

Davis

Atkins

Tucker

et al. 2008

2008 IEEE Antennas and Propagation Society International Symposium

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Section: Introductionmentioning

confidence: 99%

A null-field method for estimating underground position

Davis

Atkins

Tucker

et al. 2008

2008 IEEE Antennas and Propagation Society International Symposium

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“…2) On Electric Conductivity: Conductivity gives rise to eddy currents that produce an out-of-phase secondary field [18]. This field superimposes with the primary field, thus distorting the dipole field shape.…”

Section: A Underground MI Transmission Mediummentioning

confidence: 99%

“…This decay is associated with the skin effect [19]. However, the conductivity of most underground materials is sufficiently low, such that eddy currents can be ignored at very low frequencies [18], [19]. For example, for the 2.5-kHz carrier used in this paper, the skin depth (defined as the distance at which the signal attenuates by 1/e, i.e., approximately 8.6 dB) exceeds few tens of meters for the vast majority of rocks and minerals, as shown in Section II-A3.…”

Section: A Underground MI Transmission Mediummentioning

confidence: 99%

Underground Incrementally Deployed Magneto-Inductive 3-D Positioning Network

Abrudan

Xiao

Markham

et al. 2016

IEEE Trans. Geosci. Remote Sensing

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Underground mines are characterized by a network of intersecting tunnels and sharp turns, an environment which is particularly challenging for radiofrequency based positioning systems due to extreme multipath, non-line-of-sight propagation, and poor anchor geometry. Such systems typically require a dense grid of devices to enable 3-D positioning. Moreover, the precise position of each anchor node needs to be precisely surveyed, a particularly challenging task in underground environments. Magnetoinductive (MI) positioning, which provides 3-D position and orientation from a single transmitter and penetrates thick layers of soil and rock without loss, is a more promising approach, but so far has only been investigated in simple point-to-point contexts. In this paper, we develop a novel MI positioning approach to cover an extended underground 3-D space with unknown geometry using a rapidly deployable anchor network. The key to our approach is that the position of only a single anchor needs to be accurately surveyed-the positions of all secondary anchors are determined using an iterative refinement process using measurements obtained from receivers within the network. This avoids the particularly challenging and time-intensive task in an underground environment of accurately surveying the positions of all of the transmitters. We also demonstrate how measurements obtained from multiple transmitters can be fused to improve localization accuracy. We validate the proposed approach in a man-made cave and show that, with a portable system that took 5 min to deploy, we were able to provide accurate through-the-earth location capability to nodes placed along a suite of tunnels. IndexTerms-Localization, magneto-inductive (MI), underground.

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“…These magnetic fields are generated by beacons placed at distances of up to several hundreds of meters from the receiver. Localization methods relying on assumption of pure magnetic dipole model [33] are effective for applications in natural environments such as underground cave mapping [34][35][36]. However, building walls with concrete reinforcements may distort the beacons magnetic field, and thereby, significantly reduce localization accuracy.…”

Section: Introductionmentioning

confidence: 99%