scholarly journals A towed magnetic gradiometer array for rapid, detailed imaging of utility, geological, and archaeological targets

2021 ◽  
Vol 10 (2) ◽  
pp. 313-323
Author(s):  
M. Andy Kass ◽  
Esben Auken ◽  
Jakob Juul Larsen ◽  
Anders Vest Christiansen
Keyword(s):  
Magnetic Field ◽  
Large Range ◽  
Differential Gps ◽  
Buried Structures ◽  
Noise Floor ◽  
Inertial Measurement ◽  
Improve Accuracy ◽  
Vector Information ◽  
Towing Speed ◽  
Detailed Imaging

Abstract. Efficient and accurate acquisition of magnetic field and gradient data have applications over a large range of environmental, archaeological, engineering, and geologic investigations. Developments in new systems and improvements in existing platforms have progressed to the point where magnetic surveying is a heavily used and trusted technique. However, there is still ample room to improve accuracy and coverage efficiency and to include reliable vector information. We have developed a vector magnetic gradiometer array capable of recording high-resolution field and gradient data over tens of hectares per day at 50 cm sensor spacing. Towed by an all-terrain vehicle, the system consists of eight vertical gradiometer sensor packages and incorporates differential GPS and an inertial measurement system. With a noise floor of around 6 nT at 15 km/h towing speed and 230 Hz sample rates, large areas can be mapped efficiently and precisely. Data are processed using a straightforward workflow, using both standard and newly developed methodologies. The system described here has been used successfully in Denmark to efficiently map buried structures and objects. We give two examples from such applications highlighting the system's capabilities in archaeological and geological applications.

scholarly journals A towed magnetic gradiometer array for rapid, detailed imaging of utility, geological, and archaeological targets

2021 ◽  
Author(s):  
M. Andy Kass ◽  
Esben Auken ◽  
Jakob Juul Larsen ◽  
Anders Vest Christiansen
Keyword(s):  
Magnetic Field ◽  
Large Range ◽  
Differential Gps ◽  
Buried Structures ◽  
Noise Floor ◽  
Inertial Measurement ◽  
Improve Accuracy ◽  
Vector Information ◽  
Towing Speed ◽  
Detailed Imaging

Abstract. Efficient and accurate acquisition of magnetic field and gradient data have applications over a large range of environmental, archaeological, engineering, and geologic investigations. Developments in new systems and improvements in existing platforms have progressed to the point where magnetic surveying is a heavily used and trusted technique. However, there is still ample room to improve accuracy, coverage efficiency, and to include reliable vector information. We have developed a vector magnetic gradiometer array capable of recording high resolution field and gradient data over tens of hectares per day at 50 cm sensor spacing. Towed by an all-terrain vehicle, the system consists of 8 vertical gradiometer sensor packages, and incorporates differential GPS and an inertial measurement system. With a noise floor of around 6 nT at 15 km/h towing speed and 230 Hz sample rates, large areas can be mapped efficiently and precisely. Data are processed using a straightforward workflow, using both standard and newly developed methodologies. The system described here has been used successfully in Denmark to efficiently map buried structures and objects. We give two examples from such applications highlighting the system’s capabilities in archaeological and geological applications.

scholarly journals Testing of the Possibilities of Using IMUs with Different Types of Movements

2014 ◽  
Vol 12 ◽  
pp. 61-66 ◽  
Author(s):  
Pavol Kajánek
Keyword(s):  
Inertial Navigation System ◽  
Low Cost ◽  
Indoor Navigation ◽  
Integrated System ◽  
Test Results ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Improve Accuracy ◽  
Different Types ◽  
Measurement Units

Inertial navigation system (INS) is a self-contained navigation technique. Its main purpose is to determinate the position and the trajectory of the object´s movement in space. This technique is well represented not only as a supplementary method (GPS/INS integrated system) but as an autonomous system for navigation of vehicles and pedestrians, also. The aim of this paper is to design a test for low-cost inertial measurement units. The test results give us information about accuracy, which determine the possible use in indoor navigation or other applications. There are described some methods for processing the data obtained by inertial measurement units, which remove noise and improve accuracy of position and orientation.

scholarly journals Dynamic Sensitivity and Noise Floor of a Bonded Magneto(Elasto)Electric Laminate for Low Frequency Magnetic Field Sensing under Strain Modulations

2015 ◽  
Vol 644 ◽  
pp. 236-239 ◽  
Author(s):  
Xin Zhuang ◽  
Marc Lam Chok Sing ◽  
Christophe Dolabdjian ◽  
Y. Wang ◽  
P. Finkel ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Output Signal ◽  
Low Frequency ◽  
Mechanical Impedance ◽  
Intrinsic Noise ◽  
Noise Performance ◽  
Noise Floor ◽  
Frequency Magnetic Field ◽  
Field Sensing ◽  
Magnetic Field Sensing

The intermediated strain can convert a magnetic field to an electric output signal in a magnetostrictive-piezoelectric layered composite via three parameters: the magnetoelastic coupling, the piezoelastic coupling and the mechanical impedance. These three parameters are dominated respectively by the magnetostrictive coefficient, the piezoelectric coefficient and the mean flexibility of material in the composite. Focusing on these three parameters, many investigations on the ME enhancement have been carried out by choosing the correct material or by adjusting the ratio between the two phases in the composite [4]. Thereafter, the noise performance of ME laminates has been studied for applications as a magnetic sensor. In the last several years, the intrinsic noise sources for both the composite and the amplifier circuit have been mathematically modeled and experimentally characterized. The passively sensed signal can be amplified by either a voltage or a charge method. Furthermore, the noise contributions from the detection electronics were also integrated in the noise performance analysis [5]. According to these studies, dielectric dissipation in the piezoelectric phase is the main contribution to the noise floor for low-frequency magnetic field sensing even though the equivalent current noise source from the electronics induce fluctuations in the output signal of the low-frequency charge detection as well [6].

scholarly journals Solar and stellar magnetic flux tubes

1996 ◽  
Vol 176 ◽  
pp. 201-216
Author(s):  
Sami K. Solanki
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Flux ◽  
Large Range ◽  
The Sun ◽  
Flux Tubes ◽  
Magnetic Elements ◽  
Turbulent Pressure ◽  
Magnetic Flux Tubes ◽  
The Magnetic Field

The magnetic field of the Sun is mainly concentrated into intense magnetic flux tubes having field strengths of the order of 1 kG. In this paper an overview is given of the thermal and magnetic properties of these flux tubes, which are known to exhibit a large range in size, from the smallest magnetic elements to sunspots. Differences and similarities between the largest and smallest features are stressed. Some thoughts are also presented on how the properties of magnetic flux tubes are expected to scale from the solar case to that of solar-like stars. For example, it is pointed out that on giants and supergiants turbulent pressure may dominate over gas pressure as the main confining agent of the magnetic field. Arguments are also presented in favour of a highly complex magnetic geometry on very active stars. Thus the very large starspots seen in Doppler images probably are conglomerates of smaller (but possibly still sizable) spots.

3D Coordinate Measurement System Using Single Camera and IMU

2011 ◽  
Vol 308-310 ◽  
pp. 351-355
Author(s):  
Syed Ghafoor Shah ◽  
Gui Li Xu ◽  
Wei Ji Ni ◽  
Yong Qiang Ye
Keyword(s):  
Inertial Measurement Unit ◽  
Vision System ◽  
Contact Point ◽  
Measurement Unit ◽  
Single Camera ◽  
Inertial Measurement ◽  
Coordinate Measurement ◽  
Improve Accuracy ◽  
Continuous Scanning ◽  
Feature Calculation

This paper proposes a new method for measuring 3D coordinates of a point using a single camera vision system. The contact point is determined by using 3D force sensors. In addition, the force limiting system has also been incorporated to improve accuracy of the results. 3D point is captured when the touching probe senses the force up to certain limit and subsequently recording of that point is initiated. The points being recorded are then processed for the required feature calculation such as distance between planes, angle, radius etc. The IMU (inertial measurement unit) initially estimates the target plane position which enables the whole system to perform the required task quickly. Hence, this system can be used for continuous scanning of any surface.

3D Magnetic Field Sensor Concept for Use in Inertial Measurement Units (IMUs)

2014 ◽  
Vol 23 (2) ◽  
pp. 324-333 ◽  
Author(s):  
Dirk Ettelt ◽  
Patrice Rey ◽  
Guillaume Jourdan ◽  
Arnaud Walther ◽  
Philippe Robert ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Field Sensor ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Measurement Units ◽  
Field Sensor

scholarly journals Application of magnetic method for mapping buried structures around archaeological site of Masjid Tuha Indrapuri

2020 ◽  
Vol 20 (2) ◽  
pp. 31-35
Author(s):  
CUT INTAN KEUMALA ◽  
TOMI AFRIZAL ◽  
MUHAMMAD SYUKRI SURBAKTI ◽  
NAZLI ISMAIL
Keyword(s):  
Magnetic Field ◽  
Field Data ◽  
Archaeological Site ◽  
Magnetic Method ◽  
Buried Structures ◽  
Entire Area ◽  
Magnetic Field Data ◽  
Total Magnetic Field ◽  
Aceh Province ◽  
Reduction To The Pole

Magnetic gradiometer survey has been conducted on the yard of the archaeological site of Masjid Tuha Indrapuri, Aceh Besar Regency, Aceh Province. The site is one of the oldest mosques erected during the Aceh Sultanate period. Magnetic method was applied for mapping archaeological structures buried beneath the surface. Total magnetic field data were measured using Proton Precession Magnetometer with grid spacing of 2 meters between stations covering the entire area of the site. Diurnal and international geomagnetic reference field data were corrected to the measured data in order to calculate total magnetic field anomalies that were influenced by the buried magnetic objects. The total magnetic field anomalies distribution shows two elongated structures with U-shaped patterns surrounding the mosque. The patterns are also revealed in reduction to the pole and derivative vertical filters of the total field anomaly data. The anomaly patterns are considered a response from the rest of the buried fences that were built around the mosque in the past.

scholarly journals Computer technology for interpreting vector measurements of the magnetic field

2021 ◽  
Vol 43 (5) ◽  
pp. 219-231
Author(s):  
T. L. Mikheevа ◽  
O. P. Lapinа
Keyword(s):  
Magnetic Field ◽  
Inverse Problem ◽  
Computer Technology ◽  
Initial Approximation ◽  
Field Vector ◽  
Automated System ◽  
Geological Interpretation ◽  
Algorithmic Support ◽  
Vector Information ◽  
The Magnetic Field

Computer technology is presented to solve the inverse problem of magnetic field vector measurements using software and algorithmic support for an automated system to interpret potential fields. The technology includes constructing a numerical model of the magnetic field of the studied area, forming an initial approximation model, assessing the depth of the sources and their magnetization. An approximation structure is used to describe the sources of anomalies (a set of uniformly magnetized polygonal prisms). To solve the problem, we used real vector measurements of the magnetic field by the components Xа, Ya, Zа, Та in the sections of Gruzsko South and Gruzsko Severnaya. Geologically, the area belongs to the central part of the Ukrainian Shield — the Kirovograd tectonic megablock. The area of work is confined to the Subotsko-Moshorin latitudinal fault zone. The possibility of comparing the results of the interpretation of anomalies on each profile by the components of the anomalous magnetic field increases the reliability of the geological interpretation of magnetic prospecting data compared to the interpretation of modular surveys. The presence of vector measurements greatly facilitates the ability to determine the parameters of anomalous objects, which makes it possible to obtain more reliable solutions to the inverse problem. The use of vector information makes it possible to localize geological sources more successfully, thereby reducing the amount of work.

scholarly journals Observations of solar small-scale magnetic flux-sheet emergence

2019 ◽  
Vol 622 ◽  
pp. L12 ◽  
Author(s):  
C. E. Fischer ◽  
J. M. Borrero ◽  
N. Bello González ◽  
A. J. Kaithakkal
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Large Scale ◽  
Magnetic Loop ◽  
Field Vector ◽  
Magnetic Flux Density ◽  
Small Scale ◽  
Flux Emergence ◽  
Vector Information

Aims. Two types of flux emergence were recently discovered in numerical simulations: magnetic loops and magnetic sheet emergence. While magnetic loop emergence has been documented well in recent years using high-resolution full Stokes data from ground-based telescopes as well as satellites, magnetic sheet emergence is still an understudied process. We report here on the first clear observational evidence of a magnetic sheet emergence and characterise its development. Methods. Full Stokes spectra from the Hinode spectropolarimeter were inverted with the Stokes Inversion based on Response functions (SIR) code to obtain solar atmospheric parameters such as temperature, line-of-sight velocities, and full magnetic field vector information. Results. We analyse a magnetic flux emergence event observed in the quiet-Sun internetwork. After a large-scale appearance of linear polarisation, a magnetic sheet with horizontal magnetic flux density of up to 194 Mx cm−2 hovers in the low photosphere spanning a region of 2–3 arcsec. The magnetic field azimuth obtained through Stokes inversions clearly shows an organised structure of transversal magnetic flux density emerging. The granule below the magnetic flux sheet tears the structure apart leaving the emerged flux to form several magnetic loops at the edges of the granule. Conclusions. A large amount of flux with strong horizontal magnetic fields surfaces through the interplay of buried magnetic flux and convective motions. The magnetic flux emerges within 10 minutes and we find a longitudinal magnetic flux at the foot points of the order of ∼1018 Mx. This is one to two orders of magnitude larger than what has been reported for small-scale magnetic loops. The convective flows feed the newly emerged flux into the pre-existing magnetic population on a granular scale.

The second spherical harmonic of the diurnal variation and the orientation of the interplanetary magnetic field

1968 ◽  
Vol 46 (10) ◽  
pp. S973-S975 ◽  
Author(s):  
G. V. Skeipin ◽  
P. A. Krivoshapkin ◽  
G. F. Krymsky ◽  
A. I. Kuzmin
Keyword(s):  
Magnetic Field ◽  
Diurnal Variation ◽  
Interplanetary Magnetic Field ◽  
Neutron Monitor ◽  
Spherical Harmonic ◽  
Cosmic Ray ◽  
Vector Information ◽  
Neutron Monitor Data ◽  
Distribution Vector ◽  
Monitor Data

The super neutron monitor data from Goose Bay and Deep River for 1965 have been analyzed to give month-to-month changes of the first and second harmonics of the solar-diurnal variation. Using these results together with various suppositions about the nature of the cosmic-ray distribution vector, information is obtained concerning the orientation of the interplanetary magnetic field.

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