The ionosphere is the region of the upper atmosphere and the study of the upper atmosphere has a significant role in monitoring, modeling and forecasting for satellite based navigation services. As India lies in a low latitude region, a more careful approach has to be taken to characterize the ionosphere due to the irregularities and equatorial anomaly conditions. In order to study the ionospheric temporal variations, a regional ionospheric model based on the Adjusted Spherical Harmonic Analysis (ASHA) is implemented. The results indicate that the ASHA model is one of the contenders for estimating ionospheric delays well for GNSS augmentation systems.
Dabbakuti, J. R. K. K., Ratnam, D. V., & Sunda, S. (2016). Modelling of ionospheric time delays based on adjusted spherical harmonic analysis. Aviation, 20(1), 1-7. https://doi.org/10.3846/16487788.2016.1162197
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