Accession Number : ADA130474

Title :   Two-Layer Model of Line-of-Sight Refractive Multipath Propagation,


Personal Author(s) : Mano,Koichi

PDF Url : ADA130474

Report Date : Jan 1983

Pagination or Media Count : 60

Abstract : The two-layer model of the line-of-sight refractive multipath propagation was examined by employing the earth-flattening system of coordinates and the result was compared with an unpublished result carried out by other workers who studied the problem in the ray-straightening system. That these results should be identical is self-evident in principle provided the analysis is carried out rigorously. However, different approximations are used in the two methods, so it must still be demonstrated that the two methods given the same result in practice as well as in theory. The atmosphere is assumed to consist of two layers. The lower layer, which is immediately above the earth's surface, is a non-ducting one, typically the standard atmosphere, with a constant thickness, and the upper one is a ducting layer of sufficient thickness. On the condition that the height above the earth's surface and the elevation angle of the ray remain sufficiently small throughout the ray trajectory, it can be shown that the ray path in either layer may be approximated as a circular arc of appropriate radius. A comparison of our quartic equation from the Earth Flattening Method with the similar equation obtained from the Ray-Straightening Method shows that the two equations are essentially identical. Moreover, the results for the transit time between the terminals and the intensity of the received signals are also shown to be essentially the same.

Descriptors :   *Multipath transmission, *Electromagnetic wave propagation, Line of sight, Angle of arrival, Atmospheric refraction, Microwave transmission, Terrain, Approximation(Mathematics), Coordinates, Partial differential equations

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE