The Power Converter Stage of a Powerful Airborne Time Domain Electromagnetic System

2014 ◽  
Author(s):  
H.S. Saini ◽  
L.A.C. Lopes ◽  
J.M. Martinez
Keyword(s):  
Time Domain ◽  
Power Converter ◽  
Electromagnetic System ◽  
Time Domain Electromagnetic

Field tests of an experimental helicopter time‐domain electromagnetic system for unexploded ordnance detection

Geophysics ◽  
2004 ◽  
Vol 69 (3) ◽  
pp. 664-673 ◽  
Author(s):  
Les P. Beard ◽  
William E. Doll ◽  
J. Scott Holladay ◽  
T. Jeffrey Gamey ◽  
James L.C. Lee ◽  
...  
Keyword(s):  
Time Domain ◽  
Eddy Currents ◽  
Field Tests ◽  
Field Trials ◽  
Unexploded Ordnance ◽  
Signal Attenuation ◽  
Signal To Noise ◽  
Electromagnetic System ◽  
Time Domain Electromagnetic ◽  
Unexploded Ordnance Detection

Field trials of a low‐flying time‐domain helicopter electromagnetic system designed for detection of unexploded ordnance have yielded positive and encouraging results. The system is able to detect ordnance as small as 60‐mm rounds at 1‐m sensor height. We examined several transmitter and receiver configurations. Small loop receivers gave superior signal‐to‐noise ratios in comparison to larger receiver loops at low heights. Base frequencies of 90 Hz and 270 Hz were less affected than other base frequencies by noise produced by proximity to the helicopter and by vibration of the support structure. For small ordnance, a two‐lobed, antisymmetric transmitter loop geometry produced a modest signal‐to‐noise enhancement compared with a large single rectangular loop, presumably because the antisymmetric transmitter produces smaller eddy currents in the helicopter body, thereby reducing this source of noise. In most cases, differencing of vertically offset receivers did not substantially improve signal‐to‐noise ratios at very low sensor altitudes. Signal attenuation from transmitter to target and from target to receiver causes signals from smaller ordnance to quickly become indistinguishable from geological background variations, so that above a sensor height of about 3 m only large ordnance items (e.g., bombs and large caliber artillery rounds) were consistently detected.

Performance Assessment of a New Boom‐Mounted Airborne Time‐Domain Electromagnetic System

2010 ◽  
Author(s):  
William E. Doll ◽  
T. Jeffrey Gamey ◽  
Les P. Beard ◽  
Jacob R. Sheehan ◽  
Jeannemarie Norton ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Time Domain ◽  
Electromagnetic System ◽  
Time Domain Electromagnetic

Performance Assessment of a New Boom-Mounted Airborne Time-Domain Electromagnetic System

2010 ◽  
Author(s):  
William E. Doll ◽  
T. Jeffrey Gamey ◽  
Les P. Beard ◽  
Jacob R. Sheehan ◽  
Jeannemarie Norton ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Time Domain ◽  
Electromagnetic System ◽  
Time Domain Electromagnetic

scholarly journals The Joint UAV-Borne Magnetic Detection System and Cart-Mounted Time Domain Electromagnetic System for UXO Detection

2021 ◽  
Vol 13 (12) ◽  
pp. 2343
Author(s):  
Yaxin Mu ◽  
Wupeng Xie ◽  
Xiaojuan Zhang
Keyword(s):  
Magnetic Field ◽  
Time Domain ◽  
Field Experiments ◽  
Feature Vector ◽  
Detection System ◽  
Electromagnetic System ◽  
Joint System ◽  
Survey Mode ◽  
Electromagnetic Data ◽  
Time Domain Electromagnetic

For unexploded O=ordnance (UXO) detection, individual technology cannot achieve the best detection performance. The new detection mode of joint magnetic and electromagnetic method has attracted more and more attention. In this paper, a newly developed joint detection system is introduced, a multi-rotor UAV-based magnetic system (UAVMAG) and a cart-based time-domain electromagnetic detection system (TDEM-Cart) are combined, and the cooperative processing of magnetic field and electromagnetic data is proposed. The result of the joint inversion fuses the feature vector retrieved from the magnetic field data and the feature vector inverted from the electromagnetic data, providing more accurate positioning results and richer information, which is favorable to locate and distinguish the UXO. Two field experiments are conducted, and the results show that when the joint system works in the full-coverage survey mode, both ferromagnetic and non-ferromagnetic metal targets can be detected, avoiding missed detections. In addition, when the joint system works in the cued survey mode, the detection efficiency is improved, the positioning accuracy of joint interpretation is less than 10 cm, and it shows satisfactory performance in the recognition of targets.

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