Loran-C ground-wave propagation prediction based on the calibrated two-way NAPE algorithm

Propagation characteristics of Loran-C signals in the irregular terrain are analyzed by the calibrated two-way narrow angle parabolic equation (NAPE) method. As we only concerned with the signal waveform of the first three cycles in the time domain, most of the backward waves have not yet arrived at the moment observed. For the amplitude of the Loran-C signal in each cycle is not fixed, the backward waves in certain regions are calculated and calibrated with the function of range. It is shown that the proposed method has better results than the original one.