Research on target localization method based on characteristic frequency of empirical mode decomposition

In recent years, aiming at the increasingly serious pipeline damages because of the artificial factors, we investigate the characteristic of seismic signals and develop a monitoring and precaution system for security of pipelines based on multi-seismic sensors. There are many data acquisition modules to collect the seismic signals generated by the ground targets. The non-stationary signal analysis method based on empirical mode decomposition is applied to process the seismic signals, identify the classification and localize the threat. In this paper, it proposes a new passive localization approach based on HHT (Hilbert-Huang Transform) characteristic frequency and TDOA (time difference of arrival). It is very important to estimate the time delay of arrival in TDOA theory. But the seismic signal is non-stationary and it is difficult to obtain the characteristic frequency. The seismic signals generated by different targets were acquired by many geophones and detection modules. Then it was applied to decompose according to empirical mode decomposition and obtain the energy distribution. The characteristic frequencies are selected on the basis of energy features as principal components. The signal is reconstructed by the principal components which contain most characters of original signal. The HHT is used to calculate the instantaneous features such as instantaneous frequency, amplitude. The time difference can be deduced from the arrival of principal frequency components. The arrival time difference, sensor layout and the relative position of target and sensors are analyzed and the target localization can be achieved. The proposed method above has proved effective by the experiment data analysis.