Accession Number : ADP006166

Title :   The Parabolic Equation Approach to Predicting Tropospheric Propagation Effects in Operational Environments,

Corporate Author : JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB

Personal Author(s) : Dockery, G. D. ; Thews, Eric R.

Report Date : SEP 1989

Pagination or Media Count : 9

Abstract : The Electromagnetic Parabolic Equation (EMPE) propagation program, which was developed at The Johns Hopkins University Applied Physics Laboratory (APL), has been demonstrated to predict accurately the propagation of electromagnetic energy energy in environments with complicated refractivity characteristics. The validation and application of EMPE have also necessitated the development of new atmospheric measurement techniques as well as methods for representing realistically the range variations of refractivity structures. In this paper, a brief description of the parabolic equation approach and solution technique is first presented; comparisons with other propagation models are included. The measurement techniques that have been used to obtain accurate, high-resolution refractivity data are then discussed. Examples of how such refractivity data, in conjunction with a refractivity range-interpolation algorithm, have been used in EMPE to obtain good agreement with measured signal levels are also presented. The problem of developing a useful decision aid for operational systems based on the EMPE program is then addressed.

Descriptors :   *ELECTROMAGNETIC WAVE PROPAGATION, *TROPOSPHERE, PREDICTIONS, ATMOSPHERIC REFRACTION.

Subject Categories : Radiofrequency Wave Propagation
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE