摘要
时间域航空电磁系统的传统记录方式存在不能探测高导异常等不足。以导电薄板为模型,研究了梯形波激励、全波形记录方式下的探测分辨率。采用等效涡流环近似方法,在计算了任意位置两线圈互感的基础上,实现了薄板电流关断期间和断开期间感应电动势的数值计算。数值计算表明：当存在覆盖层时,如果测量系统最小分辨率为5 nV/m2,在电流断开期间可检测目标体电导为1~400 S,在电流关断期间可检测目标体电导为0.1~1 000 S。时间域航空电磁系统采用全波形测量,可以拓宽电磁系统检测异常电导的分辨率孔径。
The traditional record method of airborne TEM system has the difficulty to detect high-conductivity anomaly.With thin sheet model,this paper studies the detection resolution of the full-waveform TEM response induced by a trapezoid wave.An approximate method basing on eddy currents is used to estimate the mutual inductance of two coils at any position,and applied to compute the induced electromotive force of a slab model during switch-off and off time.Numerical results indicate that if minimum signal resolution of survey system is 5 nV/m2 in the case of conductive overburden,the detectable conductance range is 1~400 S during off time and 0.1~1 000 S during switch-off time.When full-waveform method is adapted to the airborne TEM system,it could broaden the conductance resolution aperture of airborne TEM.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2011年第3期885-891,共7页
Journal of Jilin University：Earth Science Edition
基金
国家'863'计划重大项目(2006AA06A205-3)
吉林省科技支撑计划重点项目(200900354)
关键词
航空电磁响应
等效涡流环
关断期间
断开期间
导电覆盖层
高导异常
airborne electromagnetic responses
eddy currents
switch-off-time
off-time
conductive overburden
high conductance anomaly
