Propagation of the low frequency groundwave over nonuniform terrain
Abstract
This report examines the utility and limitations of the integralequation representation of groundwave propagation over nonuniform terrain. Emphasis is on frequencies between 20 kHz and 200 kHz. The onedimensional version of the integral groundwave equation is subject to errors caused by: topographic irregularities near the greatcircle propagation path; finite ground conductivity; nonuniformities in the earth's electrical properties; and an approximate integration to reduce the dimension of the equation from two to one. Each of these errors is quantified, and the types of terrain to which the integral groundwave equation is applicable are defined. A method of numerical solution is developed and used to obtain results for the special case of a smooth, uniform, spherical earth. These results are compared in detail with numerical results obtained from the widely used residueseries representation of groundwave propagation. The agreement between the two methods is shown to be excellent. Graphical results are given for the groundwave attenuation function.
 Publication:

Final Report
 Pub Date:
 March 1978
 Bibcode:
 1978psrc.reptS....F
 Keywords:

 Electromagnetic Wave Transmission;
 Ground Wave Propagation;
 Approximation;
 Error Analysis;
 Loran;
 Numerical Analysis;
 Wave Attenuation;
 Communications and Radar