A Bird Calibration Device of Helicopter-Borne TEM with Concentric Bucking Loop
详细信息
- 责任者：Wang Shilong (Key Laboratory of Geo-Exploration Instrumentation ; Ministry of Education ; Jilin University ; Changchun 130026 ; China) ; Wang Yanzhang
- 刊名：Chinese Journal of Geophysics
- 出版年：2011
- 卷期：54(9)
- 关键词：航空电磁法 ; aero-electromagnetic methods ; 时间域分析 ; time-domain analysis
- 页码：p.2397-2406
- 图表：illus., 1 table, 22 refs.
- 分类号：1600
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
The multiple instrument calibrations of flying helicopter-borne time domain electromagnetic method （HTEM） can eliminate the environmental time-varying effect on the system during flight. Using the bird calibration device to solve the problem that the wire-loop method can＇t achieve, we consider the bird model o~ HTEM with the concentric bucking loop, propose the bird device space models and the coil circuit models, and analyze the transmitter magnetic field distribution, the bucking loop＇s effect and the relationship between it and the receiving coil, the space information of the calibration device and its signal detecting method. Conclusions are as follows： （1） the bucking loop that losses 0.89% of the transmitting area can increase 44.5 dB of the signal dynamic range. （2） The calibration device is levelly placed between the bucking loop and the transmitting coils. If it has more turns and greater radius and it is closer to the bucking loop, its signal response is stronger. （3） When the inductance of calibration coilbecomes greater and its resistance is less, its exponential decay becomes slower. The signal detection time point is directly decided by damping character of receiver coil which has matching resistance. We do experiments about the calibration curve characters and the device coil displacement. The relative error about the time constant of the device characteristics is less than 1, 3%, which proves the validity of the coil circuit models and device space models. The proposed models and approaches are also applicable to the bird calibration device research about HTEM with the eccentric bucking loop and the known wire-loop static testing on the high resistance ground.