Design Of Underground Source Location Feature Extraction System Based On FPGA

The location of shallow underground seismic source is the first problem to be solved in the evaluation of underground damage effectiveness of high-value penetrating ammunition,and the core of high precision location is to acquire the characteristic information related to the location of the seismic signal after the source travels through shallow geology from the surface,and to establish a high precision source location model.In the process of source localization using wireless sensor networks,because of the complexity of shallow geological structure and the randomness of inclined sites,feature extraction is very important to achieve high-precision positioning.Moreover,the sensor network has many monitoring nodes and large amount of original data returned,which cannot meet the needs of rapid location of underground seismic sources.To solve the above problems,this paper designs and develops a location feature parameter extraction system based on FPGA.The system consists of vibration multi-channel distributed sensor and its acquisition module,wireless communication module,storage module,etc.It supports the functions of variable sampling rate,remote setting and data transmission,signal preprocessing and feature extraction.Aiming at the characteristics of source location signal and the requirement of feature extraction,the engineering selection strategy of key parameters of adaptive filter is studied.Based on the analysis of the first arrival time of STA/LTA and the time difference information extraction method of multi-channel sensor by spectral decomposition.The selection method of optimal feature function and time window length and the extraction method of time difference feature of arrival of distributed sensor channels are proposed.On the basis of theoretical simulation and logical simulation verification,on the basis of FPGA,the modules of adaptive filter,time of arrival extraction and multi-spectral time difference extraction are designed and implemented.The application practice of engineering test shows that: the location feature parameter extraction system based on FPGA developed in this paper can effectively extract the arrival time and location time difference information,greatly compress the transmission information,and improve the location efficiency.