基于形态-CEEMD的地磁测量去噪方法

Geomagnetic Signal De-noising Method Based on Morphological Filter and CEEMD

针对电子设备以及供电系统工作时产生的高频磁干扰以及载体经过强磁体时的强脉冲干扰,提出基于广义形态滤波和完备经验模态分解(CEEMD)的地磁测量降噪方法。使用广义的形态滤波器滤除原始信号的尖端脉冲干扰信号,以解决CEEMD对高幅值尖端脉冲干扰分解时存在的模态混叠现象,并对比了不同结构元素的形态滤波效果。计算CEEMD分解后的本征模态函数(IMF)的自相关系数,选取合适的分界点,将含噪IMF与有用IMF有效分离,对噪声分量进行均值滤波后和有用模态分量共同重构目标信号。实验表明,该方法能有效滤除高幅值尖端脉冲干扰,提高地磁测量精度。

Aiming at the carrier and environmental magnetic anomaly interference of magnetic sensor in the practical application of underwater geomagnetic navigation,a signal de-noising method based on complete integrated empirical mode decomposition(CEEMD)and normalized autocorrelation function is proposed.The measurement signal is decomposed into multiple intrinsic mode functions(IMF)by CEEMD method,and the normalized autocorrelation function of each IMF is calculated.According to the characteristics of the autocorrelation function,a threshold evaluation rule based on normalized autocorrelation function of IMFs is pro⁃posed.The IMFs of the high geomagnetic signal ratio are selected,and the remaining IMFs are processed by mean filter.After that,the signal reconstruction is performed together with the useful modal components to obtain the geomagnetic information after de-nois⁃ing.The simulation results show that the improved CEEMD is better than the traditional CEEMD de-noising method,and the root mean square error is reduced by about 53%.The experimental results show that the improved method can effectively filter out the unsteady noise.