The Design And Implementation Of Signal Processing System For Impulse Ground Penetrating Radar

Ground Penetrating Radar(GPR)is a detection device based on the principle of high-frequency electromagnetic wave reflection.It can effectively detect and analyze the position,structure,shape and other physical information of underground target objects based on the time domain and frequency domain information of the detected echoes.Pulse GPR has the advantages of high frequency bandwidth,fast response,high resolution,wide detection range,low cost and no damage.It is widely used in geological exploration,emergency rescue,archaeological research,urban underground pipeline planning,building strength testing,bridge structure assessment and other areas.The GPR echo signal contains a wealth of information of the detected object,but at the same time carries a lot of interference and noise,which has a great influence on the accuracy of the detection result.this paper improves the system performance by eliminating interference and noise in the echo signal through hardware design and algorithm optimization.In the aspect of signal conditioning,a low-noise amplifier circuit,a sampleand-hold circuit and a variable gain amplifier circuit are designed,which can effectively convert the high-frequency signal received by the GPR into a lowfrequency signal and filter out a part of the noise.In terms of signal acquisition,high-speed equivalent sampling of echo signals is achieved using a highperformance ADC.The design ideas and circuit schematics of each circuit are given in the paper.In the aspect of signal preprocessing,the direct wave and noise filtering algorithms based on the mean,filter and space projection are introduced respectively.The basic principle and implementation process of the algorithm are given.The effectiveness of the algorithm is verified by simulation experiments.In the aspect of signal projection imaging,the defects of the standard BP(Back Projection,BP)algorithm are analyzed.Based on this,an improved distributed weighted BP imaging algorithm is proposed.Simulation experiments show that the computational complexity of the improved BP algorithm is significantly reduced,and the clutter and sidelobe suppression ability is improved.Based on hardware design,the data processing software of the pulse GPR host computer is designed.On the basis of detailed analysis of functional requirements,the functional modules of the software are reasonably planned.In addition,the design principles and layout style of the software interface are introduced,and application examples are given.Finally,the system is tested experimentally,and the results show that the system can accurately receive echoes and effectively detect underground targets.