Study on the Improved Method for Calculating Traveltime and Raypath of Multistage Fast Marching Method

The traditional Fast Marching Method (FMM) based on the finite-difference scheme can solve traveltime of first arrivals; however, accuracy and efficiency FMM are usually affected by schemes grid size. Vidale double-grid technology adopted to replace first-order second-order in this paper improve computation efficiency. does not provide corresponding raypath calculation methods, view interoperability linear travel time interpolation (LTI) method, we introduce method into ray tracing compute take consideration secondary source located inside cell stability calculation. With these measures application multistage approach, successfully completed improved Multistage (MFMM) tracing, which track arrivals any type primary multiple reflection waves. Through theoretical actual field model tests, MFMM proven be higher than that under schemes, correctness effectiveness for verified, has demonstrated good adaptability complex models. improvements applied two-dimensional cases need extended three-dimensional situations.