Calculation of full-waveform airborne electromagnetic response with three-dimension finite-difference solution in time-domain
Calculation of full-waveform airborne electromagnetic response with three-dimension finite-difference solution in time-domain
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发表时间：
2012
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通讯作者：
Xu Yangcheng;Lin Jun;L. Suyi;Zhang Xiaoshuang;Wang Yuan;Jia Yanju
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作者：
Xu Yangcheng;Lin Jun;L. Suyi;Zhang Xiaoshuang;Wang Yuan;Jia Yanju
全波形机载电磁探测以其高精度解译、高分辨率等优点，已成为新一代机载电磁探测的趋势。本文基于无源有限差分解法，将发射机电流分解为若干个小的梯形脉冲，将这些梯形脉冲在时域激发的电磁场转化为空间初始场。在迭代过程中，在有限差分方程中引入有限差分方程，将有源有限差分方程转化为有源有限差分方程。将有限差分方程逐步转化为无源有限差分方程，最终解决发射机电流为任意波形时，采用时域三维有限差分解计算全波形机载电磁响应。结果表明，采用梯形波发射时，典型地电模型空气时域机载电磁响应计算的稳定时间可超过10 ms。与积分方程解相比，第二场响应平均误差发射线圈中心误差小于1%。全波形三维有限差分解的实现为全波形三维反演和设备设计提供了基础。
The full waveform airborne electromagnetic exploration has become a trend of new-generation airborne electromagnetic exploration,due to its advantages of high-precision interpretation and high-resolution.This paper is based on the passive finite-difference solution to decompose the transmitter current into several small trapezoid impulses,and transform the electromagnetic field excited by these trapezoid impulses in time-domain into initial field in space.During the iteration step,finite-difference equations are introduced in the finite-difference equations.It transforms the active finite-difference equations into passive finite-difference equations gradually.It will work out the calculation of full-waveform airborne electromagnetic response with three-dimension finite-difference solution in time-domain eventually,when the transmitter current is in arbitrary waveform.The results show that the stabilization time of calculation for the airborne electromagnetic response of typical geoelectric models in air time-domain can exceed 10 ms with trapezoid-wave transmitting.Compared with the integral equation solution,the average error of response of second field in the center of transmitter coil is less than 1%.The realization of full-waveform three-dimension finite-difference solution provides a foundation for full-waveform three-dimension inversion and equipment design.