Decomposition of LF Resultant Waves With Multipropagation Modes in the Earth-Ionosphere Waveguide

Decomposition work of Loran-C resultant waves propagating in the Earth-ionosphere waveguide is concentrated on in this article. Resultant waves of different Earth-ionosphere models are predicted by the FDTD method first. The inverse fast Fourier transform (IFFT) spectral-division technique combined with a filtering process is employed to estimate the delays of different wave-propagation modes in the resultant waves, whereas the amplitudes are solved with the least-square method. Finally, accurate field strengths and delays of different modes (ground waves and skywaves of diverse hops) are obtained, which are important for Loran-C receivers to optimize their performances.