A numerical method for estimating tropospheric radio wave propagation for remote monitoring geoinformation systems

Present research deals with the numerical methods for the electromagnetic wave propagation around the Earth. The non-local boundary conditions for finite-difference Pade approximation of the one-way Helmholtz equation are obtained. A linear dependence of the refractive index on the height outside the computational domain can be taken into account. Thus, the proposed method is suitable for tropospheric radio wave propagation problems. The proposed approach gives an opportunity to solve the original problem without introducing artificial absorbing layer in the vicinity of the upper boundary. Pade approximants allows one to carry out the calculations with a rather large step along the longitudinal coordinate, which has a positive effect on performance. The method does not impose any significant limitations on the maximum propagation angle and can be used for two-dimensional scattering problems. Comparison with the results obtained by the split-step Fourier method and Crank–Nikolson scheme is given.