THE 1D INVERSION METHOD OF AIRBORNE TEM FOR INACCURATE ALTIMETER DATA
MAO Li-feng1, CHEN bin2, LV Dong-wei1
1. Key Lab of Earth Exploration and Information Techniques, Chengdu University of technology, Chengdu 610059, China;
2. Aero Geophysical Survey and Remote Sensing Center for Land and Resources, Ministry of Land and Resources, Beijing 100083, China
In the airborne electromagnetic survey, the altimeter data of transmitter coil are often inaccurate, which can affect the inversion result and give spurious anomalies. To overcome these shortcomings, this paper presents a 1D inversion method of airborne electromagnetic data in time-domain for inaccurate observed transmitter height. The inversion algorithm, using observed voltage data, can invert geo-electrical parameters and transmitter coil height simultaneously. The algorithm applies a regularized inversion algorithm to overcome the typical ill-condition inversion problem, and the regularized factors are calculated with an adaptive style based on the relationship between the data object function and the model object function so that the iterative inversion can be steadily carried out. The validity of the inversion method was tested using the helicopter airborne electromagnetic data as an example in this paper, which was performed by adoption of theoretical model response data with the addition of random noise. The inversion result shows that no mater whether the initial height value is higher or lower than the true value, the inversion algorithm can reconstruct subsurface medium parameter and transmitter coil height very well. The more accurate the transmitter coil height used as the inversion initial value is, the faster the convergence rate of inversion iteration and the better the inversion effect will be.
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