Research On Underground Pipe Detection Method Of Polarimetric Chaotic Ground Penetrating Radar

Due to the improvement of urban transportation facilities,the distribution of urban underground pipelines is gradually becoming more complicated.However,in the process of project maintenance and construction,the information about the underground pipelines may be lost by time,which can lead to the damage of buried pipelines in the excavation works.And then accidents occur,such as water cut-off,power outages,and explosions.Therefore,accurate detection of underground pipeline locations is very important for urban construction development.Ground penetrating radar is a non-destructive detection technology that obtains information about unknown underground targets by sending and receiving high-frequency electromagnetic waves.It has the characteristics of fast,safe,simple,low-cost,and non-destructive detection.The polarimetric state is an important information for investigating the vector characteristics of electromagnetic waves,and it can be used to determine the properties of the target such as direction,inclination,and shape.In addition,it has advantages in filtering,enhancement,and anti-jamming,which help to obtain a robust detection capability and thus improve object discrimination.For this reason,the polarimetric properties of ground penetrating radar have attracted wide attention,and it has gradually shifted from single-polarization to multi-polarization and even mixed-polarization measurements.In this thesis,a polarimetric chaotic ground penetrating radar system is set up,which uses chaotic signals as the transmitting signals.Moreover,a data fusion algorithm is used to fuse the multi-polarization echo signals.The localization and distribution detection of underground pipelines can be achieved by combining the data fusion method with the polarimetric chaotic ground penetrating radar.The main works of this thesis are as follows:(1)Review the research progress on ground penetrating radar.The basic principles of ground penetrating radar and the polarimetric principle of electromagnetic waves are also analyzed.In addition,four common data detection methods for ground penetrating radar have been introduced.(2)The simulation model of polarimetric chaotic ground penetrating radar is established,and the response characteristics of the pipeline with different distribution states under different polarimetric states are analyzed.Additionally,four kinds of data fusion methods,namely,the weighted average algorithm,the principal component analysis algorithm,the multi-scale wavelet transform algorithm,and the laplacian pyramid algorithm,are used to fuse the polarimetric components.The simulation results show that the polarimetric chaotic ground penetrating radar based on the laplacian pyramid algorithm can accurately detect underground pipelines.(3)The experimental system of polarimetric chaotic ground penetrating radar is set up to detect underground pipelines.The experimental results are consistent with the simulation results,which prove that the proposed method can accurately detect the underground pipeline.Furthermore,under the same conditions,the polarimetric chaotic radar and the polarimetric stepped frequency radar are used to detect buried pipelines,respectively.The experimental results show that the polarimetric chaotic ground penetrating radar has the ability to detect deeper targets with high accuracy.