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Research On Signal Processing Arithmetic Of Subsurface Ground Penetrating Radar

Posted on:2004-12-27Degree:DoctorType:Dissertation
Country:ChinaCandidate:L J KongFull Text:PDF
GTID:1118360125963970Subject:Signal and Information Processing
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Ground penetrating radar (GPR) is an impactful detection method of buried targets developed in these decades and have been broadly used in the world. Compared with other detection method, for example, resistivity, EMI and seismology et al. ground penetrating radar has many advantages. So GPR is always one of the researching hotspots in the world in these years and has become one important branch of remote sensing. Although designing GPR is very complex and difficult, there are an increasing number of applications in all kinds of fields. So the research of GPR is very significant for the development of civil economy.The research of GPR for middle and deep application has been comparatively mature. But GPR for short application has many aspects necessary to be deeply researched. At the same time, there are no research reports about GPR for short application in our country. So the author begins to research the signal processing algorithms of GPR for short application. The research emphases in this dissertation are the precise evaluation of wave speed in medium, clutter reduction, synthetic aperture algorithms, stepped frequency GPR, the effect of wave speed error for synthetic aperture algorithms et al.The main content of this dissertation can be concluded as following:On the basis of the signal features of subsurface penetrating radar, extraction of edge contours which uses zero-crossing points and others traditional methods are discarded. The method of extremum is given for extraction of edge contours. The edge contours of the targets can be extracted more accurately using the method of extremum and the new method generates less data for Hough Transform. According to the analysis of Hough Transform and the deficiency of traditional Hough Transform, an improved Hough Transform is proposed in which a FIR low-pass filter is added to improve the accuracy of Hough Transform. The improved Hough Transform has better performance than the traditional Hough Transform by the evaluation for the practical data.The relative curve between the loss of SNR of pulse compression filter and ,and the relative curve between pulse compression ratio and are given through the anslysis for pulse compression filter of ground penetrating radar(GPR). We draw some useful conclusion from the analysis of pulse compression filter which is very useful for the design of ground penetrating radar.On the basis of the signal features of subsurface penetrating radar, an effective method of eliminating ringing effect for GPR is given. And it can improve the resolution of GPR.When using synthetic aperture processing based on Kirchhoff migration for subsurface GRR, the SNR (Signal to Noise Ratio, SNR) of the image is very low. The author gives one modified synthetic aperture processing algorithm based on Kirchhoff migration for improving the SNR of the image. The processing result of practical data is also given. It is very difficult how to scale the azimuth resolution of GPR. The author gives one method of scaling the azimuth resolution for subsurface GPR. And the simulation result is also given.The author use many kinds of synthetic aperture processing algorithms for subsurface GPR, then draw a conclusion that synthetic aperture processing algorithms based on holographic imaging and based on Stolt migration is better for subsurface GPR.Based on the scaling azimuth resolution method given by the author, the effect of wave speed error for synthetic aperture processing algorithms based on holographic imaging is given. The relative curve between wave speed error and azimuth resolution is given.Based on the scaling azimuth resolution method given by the author, the effect of wave speed error for synthetic aperture processing algorithms based on Stolt migration is given. The relative curve between wave speed error and azimuth resolution is given.Because continuous wave stepped frequency radar has higher average power and relative bandwidth, it has been comprehensively applied with better azimuth resolution and penetration depth in...
Keywords/Search Tags:Ground Penetrating Radar (GPR), Synthetic Aperture Imaging (SAI), Clutter Reduction, Stepped-Frequency Continuous Wave Ground Penetrating Radar (SFCW-GPR), Hyperbola, Azimuth Resolution, Synthetic Aperture Radar (SAR).
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