الفهرس 
Study ObjectivesOnly 14 pages are availabe for public view
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Abstract
Since it is a very complicated stratum, the ionosphere presents a significant source of
errors for GNSS location applications. This chapter provides a summary of the case studies
conducted on the ionosphere in the current thesis and outlines the key conclusions. Lastly,
according to these results, there are a variety of parts of this study that may be further
investigated or in which new advances can be made based on the work’s research results.
6.2 Thesis Summary
This study introduces a new software TEGRO to estimate instrumental biases and TEC
using dual-frequency GPS and GLONASS observations using absolute positioning
technique. The algorithm of the software uses a geometry free linear combination of
carrier-phase and pseudo-range and then model it using spherical harmonic function of a
degree based on the geographic extent of stations. The unknowns of the model are
estimated using weighted least square based on satellite elevation angle. The solution of
weighted least square determines instrumental biases and ionospheric coefficients. These
coefficients are used to calculate TEC values on a temporal resolution of two hours.