October 1975 | NTIA Technical Report OT-75-76
R. Michael Jones; Judith J. Stephenson
Abstract: This report describes an accurate, versatile FORTRAN computer program for tracing rays through an anisotropic medium whose index of refraction varies continuously in three dimensions. Although developed to calculate the propagation of radio waves in the ionosphere, the program can be easily modified to do other types of ray tracing because of its organization into subroutines. The program can represent the refractive index by either the Appleton-Hartree or the Sen-Wyller formula, and has several ionospheric models for electron density, perturbations to the electron density (irregularities), the earth's magnetic field, and electron collision frequency. For each path, the program can calculate group path length, phase path length, absorption, Doppler shift due to a time-varying ionosphere, and geometrical path length. In addition to printing the3e parameters and the direction of the wave normal at various points along the ray path, the program can plot the projection of the ray path on any vertical plane or on the ground and punch the main characteristics of each ray path on cards.
Keywords: ionosphere; computer program; Appleton-Hartree formula; radio waves; ray tracing; Sen-Wyller formula; three-dimensional
Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.
This document contains software developed by NTIA. NTIA does not make any warranty of any kind, express, implied or statutory, including, without limitation, the implied warranty of merchantability, fitness for a particular purpose, non-infringement and data accuracy. NTIA does not warrant or make any representations regarding the use of the software or the results thereof, including but not limited to the correctness, accuracy, reliability or usefulness of the software or the results. You can use, copy, modify, and redistribute the NTIA-developed software upon your acceptance of these terms and conditions and upon your express agreement to provide appropriate acknowledgments of NTIA's ownership of and development of the software by keeping this exact text present in any copied or derivative works.