Propagation of the Low Frequency Groundwave over Nonuniform Terrain.

Abstract

This report examines the utility and limitations of the integral-equation representation of ground-wave propagation over nonuniform terrain. Emphasis is on frequencies between 20 kHz and 200 kHz. The one-dimensional version of the integral groundwave equation is subject to errors caused by: topographic irregularities near the great-circle 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 ground-wave 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 residue-series representation of ground-wave propagation. The agreement between the two methods is shown to be excellent. Graphical results are given for the ground-wave attenuation function. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1978
Accession Number
ADA057273

Entities

People

  • E. C. Field
  • Rosalind J Allen

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Accuracy
  • Asymptotic Series
  • Atmospheric Refraction
  • Boundaries
  • Cartesian Coordinates
  • Coordinate Systems
  • Dielectric Permittivity
  • Electrical Properties
  • Electromagnetic Fields
  • Equations
  • Fresnel Zones
  • Integral Equations
  • Power Series
  • Radio Navigation
  • Refractive Index
  • Two Dimensional
  • Wave Propagation

Readers

  • Calculus or Mathematical Analysis
  • Radar Systems Engineering.