Research On Reverse-Time Migration Imaging Of Antenna Array Ground-Penetrating Radar

Ground penetrating radar(GPR)is a nondestructive detection method based on the difference of electromagnetic properties of underground media.It is widely used in engineering detection,environmental investigation,mineral exploration,archaeological investigation and so on.With the increasing demand for fast and fine detection of underground structures,the conventional two-dimensional detection method of "single transmit and single receive antenna" is difficult to determine the three-dimensional position,shape and extension range of the target quickly and effectively.The method of arranging multiple parallel survey lines to detect the target area will undoubtedly increase the detection cost and working cycle.In recent years,the array antenna ground-penetrating radar system has come into people’s field of view.Conventional processing and analysis methods are difficult to directly obtain the three-dimensional spatial information of underground targets accurately from the three-dimensional ground-penetrating radar profile,and the widely used two-dimensional inverse time migration is difficult to accurately process the three-dimensional data.In view of the above problems,this paper,based on "Yakumo" array antenna ground-penetrating radar system,carries out the inverse time migration imaging research of array antenna ground-penetrating radar data.The main contents and conclusions are as follows:(1)This paper introduces the detection principle,instrument composition and arrangement of transmitting and receiving antennas of "Yakumo" antenna array ground-penetrating radar,and analyzes the advantages of "Yakumo" antenna array ground-penetrating radar system in carrying out area measurement and improving data acquisition efficiency.On this basis,the conventional data processing method and implementation process of "Yakumo" antenna array ground-penetrating radar are discussed.(2)This paper describes in detail the principle of 3D ground-penetrating radar(GPR)data reverse-time migration imaging,takes common migration data as the input of 3D reverse-time migration imaging,uses the finite-difference time-domain method as the electromagnetic wave extrapolation calculation method,and according to the conditions of zero-time imaging,the 3D reverse-time migration algorithm of antenna array GPR is compiled.The numerical simulation test,physical simulation test,field detection and migration imaging processing of a tsunami layer are carried out.The results show that,compared with the conventional migration results,the 3D reverse time migration algorithm of the array antenna ground-penetrating radar is more accurate and accurate,and can obtain the3 D distribution of underground media in the detection area more quickly and intuitively,which is more useful for subsequent interpretation.(3)This paper describes in detail the principle of 3D ground-penetrating radar(GPR)data reverse-time migration imaging,takes common migration data as the input of 3D reverse-time migration imaging,uses the finite-difference time-domain method as the electromagnetic wave extrapolation calculation method,and according to the conditions of zero-time imaging,the 3D reverse-time migration algorithm of antenna array GPR is compiled.Numerical simulation tests,physical simulation tests,field detection and migration imaging processing of a tsunami layer are carried out.The results show that,compared with the two-dimensional inverse time migration results,the 3D inverse time migration algorithm of the array antenna ground-penetrating radar is more accurate and accurate,and can obtain the 3D distribution of underground media in the detection area more quickly and intuitively,which is more beneficial to subsequent interpretation.(4)In order to solve the problem that the data volume of the antenna array ground-penetrating radar system is sparse in the direction of vertical survey line,which leads to the low imaging resolution in this direction,an interpolation method for the nearest neighbor points of the data in this direction is proposed.The inverse time migration after interpolation has higher resolution,less false image and easier recognition of the target.