RAY TRACING IN RISING AND FALLING DUCTS.
NAVAL RESEARCH LAB WASHINGTON D C
Pagination or Media Count:
In studying signal transmission beyond the horizon by elevated duct propagation, estimates are needed of the losses. These estimates can be made by application of ray tracing for models of longitudinally varying ducts. A program was written in the NELIAC language for producing ray trajectories in an atmosphere which is variable in two dimensions. The program was run in the NAREC digital computer, and the resulting plots of the ray paths are used to analyze certain of the loss mechanisms in elevated ducts. Changes of the acceptance angle, i.e., refractive index gradient at a fixed altitude can cause continued losses. Changes in duct geometry causes losses which are a function of the height slope distribution at the point of change. A third loss mechanism, that of scattering, is not handled in the present analysis, but it is pointed out that a discontinuous duct may approach the Booker and Gordon model for tropospheric scatter. Author