Target Tracking In Converted Wave Processing Technology Research

The processing methods of converted waves are mainly studied in this paper. Converted waves to be researched are produced by vibrating targets on the ground. The study is designed to filter out all kinds of noises and interferences produced while receiving the vibration signals, and extract the converted waves, and then calculate the converted wave information accurately to track the vibration targets more precise.Vibration signals generated by vibrating targets are seismic waves. Seismic waves include body waves and surface waves. Body waves are divided into longitudinal waves and shear waves. Converted waves are generated when some longitudinal waves encounter material interface and transmission or reflection phenomenon occurred. Primary waves are the fastest spreading seismic waves, they often take the form of longitudinal waves on the vibration signal waveform figure. When extracting the converted waves and the primary waves, the surface waves are the strongest interferences in addition to the random noises like industrial noises and acoustic interferences. Processing and extraction of the converted waves are aimed at the interferences and noises.The processing method of converted waves is based upon the waves’ propagation and polarization characteristics. The paper analyses the commonly used filtering methods and extracting methods. By comparing the frequency spectrum characteristics of effective signal and noises, wavelet packet filtering method is selected to decompose and reconstitute the vibration signals to filter out most of the noises. According to the polarization characteristics of seismic wave, selecting polarization filtering method to suppress the surface wave and separate the p-wave and the converted wave. The detail processing procedures of converted waves processing in using wavelet packet filtering method and polarization filtering method are presented in the converted wave information procession of the fifth chapter.The hardware system constitution, the experimental environment, the upper monitor of the acquisition system designed in Lab VIEW, the selection of vibration source and the experiment procedure are presented in converted wave information collection of the fourth chapter.Converted waves are used to target tracking, the speeds of primary waves and converted waves are measured through the experiments. The different time can be read through the extracted converted waves’ oscillogram and the extracted primary waves’ oscillogram. On the basis of the speed and time difference,the distance of the target to the receiver is calculated. The orientation of the target is gained according to the main polarization direction of the polarization filter. So the goal of tracking the ground vibrating with low error is achieved, which proves the effectiveness of the selected processing methods.