Tropospheric Effects on Signals at Very Low Elevation Angles
JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
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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.
- Radiofrequency Wave Propagation
- Unmanned Spacecraft
- Radio Communications