Ray-based crosshole radar traveltime tomography using MSFM method

We presented a ray-based iteratively traveltime tomography algorithm for crosshole radar direct-arrival data using the multistencils fast marching method (MSFM). The proposed scheme used MSFM to compute the traveltime solution at each grid point by solving the traveltime eikonal equation along several stencils and picked the solution that satisfies the upwind condition. Curved raypaths, which were needed for the construction of the Jacobi matrix during inversion, were generated using the steepest descent technique. The solutions were achieved by an iteratively linearized inversion approach. We tested the suggested method on three synthetic data sets and a field data set. The reconstruction results indicated that the MSFM algorithm is very suitable for crosshole radar traveltime tomography and the proposed scheme is considered to be an efficient crosshole radar traveltime tomography technique.