Overcoming geometric issues in the multipath propagation of electromagnetic waves using ray tracing and spherical ground surface theory

摘要

To address geometric issues in the multipath propagation of electromagnetic waves, we review three typical atmospheric refractivity models. We also examine methods usually used to calculate the effective Earth's radius and propose a new way of doing this, based on ray curvature. A new calculation method using ray tracing and spherical ground surface theory is developed that works in accordance with existing geometric models. We compare and contrast the errors produced by a traditional approach and our own approach, using four parameters: the height of the receiving antenna h(2); the grazing angle of a ray's reflection path tp; the elevation angle between the horizontal plane of the transmitting antenna and the ray that radiates from it and passes through the reflection point theta(13); and the difference between the direct path and the reflection path delta R-a. The results of this analysis illustrate the effectiveness of the new method we have proposed.