B-spline modeling of VTEC over Turkey using GPS observations

Date

2010-05-01

Author

Nohutcu, M.
Karslıoğlu, Mahmut Onur
Schmidt, M.

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In this study we propose two approaches to model the Vertical Total Electron Content (VTEC) of the ionosphere with quadratic B-spline functions. For the 2-D case, VTEC is modeled in a Sun-fixed reference frame. In the 3-D approach, the 2-D model is extended to represent the temporal variations in an Earth-fixed reference frame. The localizing features of B-splines allow resolving finer structures for the regions with a sufficient number of observations by increasing the level of functions. To reduce the effects of outliers, Iteratively Re-weighted Least Squares (IRIS) with a bi-square weighting function as a robust regression algorithm is applied for parameter estimation. Another iterative method LSQR is performed for the solution of the linear systems providing a regularization effect for ill-conditioned problems. B-spline approaches are applied to real data obtained from the ground-based GPS observations over Turkey. Results are compared with the solutions of the Bernese GPS Software.

Subject Keywords

Ionosphere modeling, B-splines, GPS, Robust regression

URI

https://hdl.handle.net/11511/51176

Journal

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS

DOI

https://doi.org/10.1016/j.jastp.2010.02.022

Collections

Graduate School of Natural and Applied Sciences, Article

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Citation Formats

M. Nohutcu, M. O. Karslıoğlu, and M. Schmidt, “B-spline modeling of VTEC over Turkey using GPS observations,” JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, pp. 617–624, 2010, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/51176.