EM-I sensor NEMFIS: method, equipment and case stories of archaeological prospection

Manstein, Yuri; Manstein, A.K.

doi:10.4000/archeosciences.1775

Cited by 4 publications

(4 citation statements)

References 1 publication

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“…At present, portable FEM detection systems include the EM series by Geonics in Canada [ 1 , 2 , 3 ], the GEM series by Geophex in the United States [ 4 , 5 , 6 ], Geovizer in Russia, and MIL-D in Italy. They have been widely used in urban underground metal pipelines [ 7 ] and metal structure exploration [ 8 ], soil pollutant distribution surveys [ 9 , 10 ], and special soil layer thickness [ 11 ] and ice layer thickness detection [ 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Digital Signal Compensation and Sounding Depth Analysis of Portable Frequency-Domain Electromagnetic Exploration System

Liu,

Wang

et al. 2024

Sensors

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Low-resistivity objects produce eddy currents when excited with electromagnetic waves of a certain frequency and then generate an eddy electromagnetic field. A portable frequency-domain electromagnetic exploration system can be used to identify this eddy electromagnetic field, and then the low-resistivity objects can be positioned. At present, portable frequency-domain electromagnetic method (FEM) exploration systems use analog signal compensation, and the sounding depth is generally calculated using empirical formulas. In order to improve the rationality of signal compensation, this paper puts forward a digital signal compensation technology, including a device design, an information extraction method, and a primary field calibration method, and makes an exploration prototype based on the digital signal compensation technology. Using 10 nV as the minimum potential detection capability, the sounding depth of the portable FEM was analyzed, and it was found that when investigating a target with the same depth, a lower frequency required a larger emission current. If this could not be met, the sounding depth became smaller, and a phenomenon appeared in which the lower the operating frequency, the smaller the sounding depth. Through the detection of known underground garages, the apparent conductivity and normalized secondary field anomalies with higher sensitivity were obtained, which indicates that the detection system based on the digital signal compensation technology is effective in practical exploration. Via long-distance detection experiments on cars, it was confirmed that the sounding depth of the portable multi-frequency FEM in practical work indeed decreases with a decrease in the operating frequency.

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Section: Introductionmentioning

confidence: 99%

Digital Signal Compensation and Sounding Depth Analysis of Portable Frequency-Domain Electromagnetic Exploration System

Liu,

Wang

et al. 2024

Sensors

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“…The frequency domain systems commonly used mainly include GEM-2 [26], GEM-3 [27,28], and GEM-5 [29] designed by by Geophex Ltd., Raleigh, NC, U.S.A., EM31-MK2 [30] and EM34-3 [31], manufactured by Geonics Ltd., Mississauga, ON, Canada, and the NEMFIS [32] system made in Russia. GEM-2 is the earliest hand-held frequency domain electromagnetic detection device, its sensor adopts a horizontal coplanar (HCP) structure, and the offset distance between transmitting and receiving is 1.66 m. Meanwhile, GEM-3 and GEM-5 are concentric sensor structures, and work in the frequency range of 90 Hz∼22 kHz.…”

Section: Introductionmentioning

confidence: 99%

Frequency Domain Electromagnetic System Based on Unmanned Aerial Vehicles Platform for Detecting Shallow Subsurface Targets

Xing

Zhang

2023

Remote Sensing

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Due to the advantages of being nondestructive, rapid, and convenient, the electromagnetic detection method has attracted growing interest in the field of shallow subsurface detection. With the rapid development of unmanned aerial vehicle (UAV) technology, the use of the UAV platform for measurement can not only improve work efficiency but also avoid the significant losses that may be caused by humans working in dangerous areas. Therefore, we propose a broadband frequency domain electromagnetic system AFEM-3 based on a UAV platform for shallow subsurface targets detection (within less than 2 m). The sensor head adopts a concentric planar coil structure with a high spatial resolution, and a bucking coil connected in reverse series with the transmitting coil is used to suppress the primary field at the receiving coil. We designed a transmitting module based on unipolar frequency multiplication sinusoidal pulse width modulation technology that can generate multi-frequency arbitrary combination transmitting waveforms with low total harmonic distortion. It can also be matched to a variety of different transmitter coils by using the same hardware circuit. In addition, the global navigation satellite system and inertial measurement unit are integrated on the sensor head. The measurement response value, position, and attitude information can be displayed in real-time through the host computer. Through the static experiment of a standard coil, we verified the consistency between the AFEM-3 system with the theory. The performance of the system was evaluated through field experiments. The experimental results show that the system can effectively detect multiple metal targets in shallow subsurface areas. For different metal targets, the AFEM-3 system can provide obvious frequency domain characteristics.

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“…The duds left during shooting training and live-fire exercises seriously restrict people's activities range. In recent years, due to its portability and efficiency, frequency domain electromagnetic system is widely used in the field, such as unexploded ordnance detection [1], shallow surface mapping [2] and archeology [3].…”

Section: Introductionmentioning

confidence: 99%

“…Currently, commercial products mainly include EM31-MK2, EM34-3, EM38 by Geonics [5,6], GEM-2, GEM-3, GEM-5 by Geophex [7][8][9] and Russian NEMFIS [3] system. Based on geometric sounding principle, EM series systems made by Geonics can achieve different depth sounding by changing the distance between transmitter and receiver and the corresponding operating frequency.…”

Section: Introductionmentioning

confidence: 99%

A Portable Frequency Domain Electromagnetic System for Shallow Metal Targets Detection

Qu¹,

Li²,

Fang³

et al. 2017

PIER M

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Abstract-In this paper, a portable frequency domain electromagnetic system CEM-2 is presented for shallow metal targets detection. This paper discusses the detection principle of frequency domain electromagnetic system, introduces hardware implementation, presents test results of each module, and gives the system's imaging results in field tests. Sinusoidal pulse width modulation technique is employed in this system to produce single-frequency or multi-frequencies synthetic electromagnetic signals with signal to noise ratio of about 85 dB. After integration, the CEM-2 system's in-phase noise level is about 90 ppm while the quadrature response is about 100 ppm. The experiment results of CEM-2 agree well with the simulation ones both from signatures and amplitudes. The experiment for detecting targets of different sizes and materials conducted in field indicates that CEM-2 system can be used to distinguish metallic and ferrous objects.

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EM-I sensor NEMFIS: method, equipment and case stories of archaeological prospection

Cited by 4 publications

References 1 publication

Digital Signal Compensation and Sounding Depth Analysis of Portable Frequency-Domain Electromagnetic Exploration System

Digital Signal Compensation and Sounding Depth Analysis of Portable Frequency-Domain Electromagnetic Exploration System

Frequency Domain Electromagnetic System Based on Unmanned Aerial Vehicles Platform for Detecting Shallow Subsurface Targets

A Portable Frequency Domain Electromagnetic System for Shallow Metal Targets Detection

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