Tropospheric Effects on Signals at Very Low Elevation Angles
Abstract
Two possible sources of error in computing a tropospheric range correction from a model are mismatch between the model and the actual refractivity profile, and neglect of a signal path bending. To study the error sources, the tropospheric range effect on a radio signal has been evaluated at different elevation angles, for some observed atmospheres, by three methods: (a) using meteorological balloon data, the effect is evaluated along the computed, curved signal path (this is our best estimate of the true effect and is the standard for comparison); (b) using meteorological balloon data, the effect is evaluated for assumed straight-line propagation; and (c) using only surface meteorological data, the effect is evaluated from the two-quartic tropospheric model for assumed straight-line propagation. The differences ((b) - (a)) and ((c) - (b)), respectively, represent the path-bending component and the profile-mismatch component of the total model error ((c) - (a)). Results are presented in figures. The effect of the model-based correction on the computation of tracking-station position is shown for a few sample cases.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1976
- Accession Number
- ADA025714
Entities
People
- Helen S. Hopfield
Organizations
- Johns Hopkins University