摘要:
航空电磁系统观测值中不仅包含了地下介质的响应,还包含多种噪声成分,其中传感器运动噪声具有频率低、幅值大、非周期等特点,是航空电磁探测系统的主要噪声源之一.针对运动噪声的上述特点,利用EEMD方法对随机信号的分解能力,将航空电磁信号分解为多阶IMFs分量;利用IMFs某阶分量拟合传感器运动噪声,并从航空电磁信号中加以去除,从而获得去除运动噪声后的信号.本文利用EEMD方法对航空电磁仿真信号中运动噪声加以识别和去除,取得了良好的效果.通过与传统样条插值方法去噪效果的对比,表明EEMD法能够有效地去除线圈中的运动噪声,同时将该方法应用于山东某地无人机半航空瞬变电磁系统实测数据处理中,取得了良好的去噪效果.
Abstract:
The observation of airborne electromagnetic (AEM) system not only includes the response of the underground media but also comprises various kinds of noise.The motion-induced noise is the main source of AEM system with the characteristics of lower frequency,higher amplitude and non-periodicity.The ensemble empirical mode decomposition (EEMD) method is an effective method for random signal decomposition which decomposes the signal into N-level intrinsic mode functions (IMF) components and residual component.The high level IMF component of low frequency is used to fit the motion-induced noise,and the noise-free signal can be obtained by reconstructing the remaining IMF component and the residual component.In this study,the authors used EEMD method to distinguish and suppress motion-induced noise for both the simulation data and the survey data,and compared the denoising result between the EEMD method and the traditional spline method.The comparison result shows that the EEMD method can remove the motion-induced noise effectively due to the high fitting ratio and thus can get higher signal-to-noise ratio.
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