| 飞行高度同时反演的固定翼航空瞬变电磁-维反演 |
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| 引用本文： | 毛立峰,王绪本,李文杰.飞行高度同时反演的固定翼航空瞬变电磁-维反演[J].地球物理学报,2011,54(8):2136-2147. |
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| 作者姓名： | 毛立峰 王绪本 李文杰 |
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| 作者单位： | 1. 成都理工大学地球探测与信息技术教育部重点实验室,成都 610059;
2. 中国地质科学院地球物理地球化学勘查研究所,河北 廊坊 065000 |
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| 基金项目： | 国家863重大项目课题"时间域固定翼航空电磁勘查系统研发"(2006AA06A206)和四川省创新团队资助计划(KYTD201002)资助. |
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| 摘 要： | 航空电磁测量记录中,不仅感生电动势测量数据有观测误差,而且高度计测量数据也有误差,直接进行常规反演往往导致反演结果不可靠,研究飞行高度数据有误差下的反演算法具有实际意义.本文以层状模型的固定翼时间域航空电磁多分量理论响应数据为例,提出了两种针对飞行高度计记录数据有误差时的正则化反演算法,一个是自适应正则化反演方法,另一...
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| 关 键 词： | 固定翼航空瞬变电磁 飞行高度 自适应正则化反演 约束反演 有限内存拟牛顿法 |
| 收稿时间： | 2010-07-24 |
Research on 1D inversion method of fix-wing airborne transient electromagnetic record with flight altitude inversion simultaneously |
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| MAO Li-Feng,WANG Xu-Ben,LI Wen-Jie.Research on 1D inversion method of fix-wing airborne transient electromagnetic record with flight altitude inversion simultaneously[J].Chinese Journal of Geophysics,2011,54(8):2136-2147. |
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| Authors: | MAO Li-Feng WANG Xu-Ben LI Wen-Jie |
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| Institution: | 1. Key Lab of Earth Exploration and Information Techniques, Chengdu University of Technology, Chengdu 610059, China;
2. Institute of Geophysical and Geochemical Exploration, Langfang Hebei 065000, China |
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| Abstract: | In the record of airborne electromagnetic survey, not only the measured voltage data but also the altimeter data have observation error; the results of conventional inversion are badly affected particularly in middle/shallow layer if inaccurate flight altitude was used in inversion. Therefore, it's a significant thing to research the inversion algorithm using observation data with inaccurate flying altitude. In this paper, the fix-wing airborne electromagnetic multi-component responses data in time domain of layered model is used as an example and two regularized inversion algorithms are presented to invert for earth resistivity and the flying altitude simultaneously aiming at the inversion problem of inaccurate flying altitude. One is the adaptive regularized inversion method and the other is constrained optimization inversion method. Combined with the restraint technique of smoothing inversion model, the flight altitude, seen as an inversion parameter in both methods, is determined along with the earth resistivity in the inversion to obtain a better interpretation result. The first algorithm is mainly used on the common occasion, for example there is little known geoelectricity information beforehand. Given the initial flight altitude (for instance, the measurement of altimeter) and the resistivity of initial half-space model, the algorithm can reconstruct the resistivity and the flight altitude steadily and reliably. The regularizing factor used in inversion is obtained adaptively and the singular value decomposition (SVD) method is used to resolve the inversion equations. The second inversion algorithm makes use of the bound constraints of the model resistivity and the flight altitude determined by the known geoelectricity information to accomplish the constrained inversion. The regularizing factor is set beforehand based on the smooth degree of the model and the optimal result of model resistivity and flight altitude is searched in the feasible region by limited-memory quasi-Newton (LMQN) optimization method. The inversion method is tested using the synthetic data of multi-layered model with noises added. The iterative process of the regularized inversion is analyzed and shown in this paper. The inversion results of different initial value of flight altitudes and different constraints of inversion parameters used in inversion are compared in this paper. It shows that both the resistivity distribution and the flight altitude are reconstructed well whatever the initial flight altitude is higher or lower; the inaccurate flight altitude data used as initial value in inversion, however, might lower the velocity of convergence of the inversion. According to the result of an example in the paper, when the given flight altitude initial value has a lower error of 15 m compared to the true flight altitude, the errors of flight altitude value from the first inversion algorithm are all less than 0.3 m after the 10th iteration, and for the second method, the flight altitude values of the inversion after 6th iteration vary from 119.4 m to 121 m, whose mean has an error of 0.2 m. |
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| Keywords: | Fix-wing airborne transient electromagnetic Flight altitude Adaptive regularized inversion Constrained inversion Limited-memory quasi-Newton method |
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