Ground-penetrating Radar In The Reverse Time Migration And Velocity Estimation

Migration techniques is a crucial step in Ground penetrating radar data processing, the aim of which is to make the diffraction wave converged and let the tilt reflection homing, and the key of this techniques is the to find the upcoming wave equation solution, firstly, the paper discussed the migration of several conventional method as well as the merit and disadvantages of each method, then the paper analyzes the traditional 15 degree equation migration algorithm, of which is unable to correctly migrate steep-dip reflections(reflections propagating at large angle),then the linearly transformed ideology is derivated, of which is essentially different from the time-retarded coordinates transformation, through more accurate and stable computation, a none-approximate equation is obtained with special difference scheme to achieve steep-dip reflection migration in constant-velocity media, then the paper extends the application it into laterally inhomogeneous media to improve the former case, a new equation is derivated with a mixed factor items added, and the preparation of the corresponding Matlab program. Then apply it to dealing with a more complicated variable-velocity model and measured data, the imaging results shows the advantage of the improved linear transformation of the migration algorithm is more flexible in dealing with the geological model of main reflector or multiple reflection particles.On this basis, the paper discusses the velocity estimates, for the velocity matrix is needed to input when running the former migration program, while, the actual operation is through repeated input attempt to approximate the true velocity matrix value, which is based on the migration effect, thus a more accurate velocity estimation method is used to reduce the errors in the process of velocity matrix importing, through which to optimize the accuracy of final migration effect with the migration program in the former case.The paper was funded by a joint support of the National Natural Science Fund, the Ministry of Education Doctoral Foundation of new teachers, the key project of Hunan Natural Science Foundation, the Science and technology projects of Hunan Province.