基于HHT的CBOOM浅剖信号分析

Analysis of the Signals of C-BOOM Subbottom Profiler Based on HHT

通过分析C-BOOM浅剖信号的时域和频域特点,观察到其信号频带较宽,和环境噪声频带重叠,而且信号重复性较差,使得无法使用傅立叶变换等传统方法对C-BOOM浅剖信号进行准确的频域参数估计和滤波。基于HHT(Hilbert-Huang Transform)方法对C-BOOM浅剖信号进行分析,通过分析筛选由EEMD(Ensemble Empiri-cal Mode Decomposition)分解得到的信号分量确定了信号频带和中心频率等频域参数,在未知信号频带的情况下完成了对信号的滤波,分离得到了C-BOOM浅剖的信号部分和环境噪声部分。通过比较分离得到的环境噪声成分和真实环境噪声的频谱,验证了信号分离方法是有效的。

When analyzing the time and frequency domains of the signals of C-BOOM subbottom profiler, it has been found that the frequency band of the signals is wide and overlaps with the frequency band of envi- ronmental noises Besides, the repeatability of the signals is so poor that traditional methods such as Fou- rier transform cannot be used for the accurate estimation of frequency-domain parameters and for filtering as well. The HHT （Hilbert-Huang Transform） method is used to analyze the signals and the frequency- domain parameters such as the frequency band and the central frequency of the signals are determined by a- nalysis and filtration of the components obtained by decomposing with EEMD. In such a way, the signals are filtered under the condition of unknowing the signal frequency band, and the signals of C-BOOM sub- bottom profiler are separated from the environmental noises. By comparing the noises obtained by the sep- aration mentioned above with the frequency spectrum of real environmental noises, the above method for the signal separation has been validated.