We have developed a novel technique for airborne time-domain electromagnetic data levelling using inequality-constrained polynomial fitting. In the approach, channel data of a certain survey area are levelled under the constraint of off-time attenuation rule. Based on the correlations between flight lines, Huang has proposed that level errors could be fitted by the differences between the flight line data and its reference line data. Thus, the level errors represented as polynomial functions are determined by the least-squares algorithm subjecting to the constraint of the adjacent channel. In addition, only the survey area data in the absence of anomalous features are used in the levelling process to avoid fake level problem. We validate the levelling method by applying it to synthetic data and field data, comparing with line-to-line correlation levelling.

中文翻译：

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基于不等式约束多项式拟合的机载电磁数据调平

我们开发了一种使用不等式约束多项式拟合的机载时域电磁数据调平新技术。该方法在关断时间衰减规则的约束下对某一测区的信道数据进行平整。根据飞行路线之间的相关性，黄提出可以通过飞行路线数据与其参考线数据之间的差异来拟合水平误差。因此，以多项式函数表示的电平误差是由最小二乘算法在相邻信道的约束下确定的。此外，在平整过程中仅使用没有异常特征的测量区域数据，以避免假水平问题。我们通过将其应用于合成数据和现场数据来验证调平方法，