Ionospheric residual range error model
Abstract
A model of the error remaining in two-frequency-corrected (TFC) Navsat data due to ionospheric effects has been developed. The model of this residual range error (RRE) is based on the relationship between the RRE and the first order range error. This approach is taken because the ionosphere is extremely variable from day to day. The first order term is a real time measure of the state of the ionosphere and can account for this variation. This study employed simulated Navsat passes observed at 12 ground stations to determine the relationship between the ionospheric range error (REI) and the RRE. A three dimensional model of the refractive index was used which included the ARL:UT ionospheric model and the Hopfield tropospheric model. It was found that the ratio of RRE to REI was a slowly varying function of elevation angle. This function was modeled with a piecewise quadratic fit to the data. The model was evaluated by subtracting the 'observations' (the simulated data) from the model predictions. This established that the model signifcantly reduced the RRE, particularly for the cases of large RRE.
- Publication:
-
International Geodetic Symposium on Satellite Doppler Positioning
- Pub Date:
- 1979
- Bibcode:
- 1979igss.conf..113C
- Keywords:
-
- Doppler Radar;
- Error Analysis;
- Ionospheric Propagation;
- Navigation Satellites;
- Range Errors;
- Satellite Transmission;
- Atmospheric Effects;
- Ionospheric Electron Density;
- Mathematical Models;
- Optical Paths;
- Ray Tracing;
- Refractivity;
- Three Dimensional Models