Non-parametric and semi-parametric regional modeling of the ionospheric vertical total electron content using ground-based GPS observations

Durmaz, Murat
Different global and regional models have been proposed for modeling of Vertical Total Electron Content(VTEC). Basis functions such as Spherical Harmonics and tensor products of univariate B-Splines are used for global and regional modeling respectively. The coefficients of the basis functions and Differential Code Biases (DCB) of satellites and receivers are treated as parameters and estimated from geometry-free linear combinations. In this work, a new approach based on non-parametric and semi-parametric methods is proposed to model spatio-temporal variations of VTEC. Multivariate Adaptive Regression Splines (MARS) and B-splines (BMARS) are adapted for regional VTEC modeling. Moreover, a semi-parametric modeling technique is developed where receiver DCBs can also be estimated. The parametric part of the semi-parametric model represents the receiver DCBs, whereas the non-parametric part is related to VTEC. The developed methods are implemented in an extensible software package. Both methods are applied to regional VTEC modeling over different regions and times. The results are compared both numerically and visually with another regional method and Global Ionosphere Maps (GIMs) provided by Center for Orbit Determination in Europe (CODE). The estimated receiver DCBs are also compared with the estimates of the other regional method and the ones that are published by CODE. Analysis of the results show that the developed technique can deliver similar VTEC maps and receiver DCB estimates with less number of terms. Additionally, the proposed method is validated by cross-validation and single-frequency point positioning indicating that the developed method is capable of delivering efficient and accurate regional VTEC models which provide better positioning estimates.


Local modeling of the ionospheric vertical total electron content (VTEC) using particle filter
Aghakarimi, Armin; Karslıoğlu, Mahmut Onur; Department of Geodetic and Geographical Information Technologies (2012)
Ionosphere modeling is an important field of current studies because of its influences on the propagation of the electromagnetic signals. Among the various methods of obtaining ionospheric information, Global Positioning System (GPS) is the most prominent one because of extensive stations distributed all over the world. There are several studies in the literature related to the modeling of the ionosphere in terms of Total Electron Content (TEC). However, most of these studies investigate the ionosphere in t...
Regional vertical total electron content (VTEC) modeling together with satellite and receiver differential code biases (DCBs) using semi-parametric multivariate adaptive regression B-splines (SP-BMARS)
Durmaz, Murat; Karslıoğlu, Mahmut Onur (Springer Science and Business Media LLC, 2015-04-01)
There are various global and regional methods that have been proposed for the modeling of ionospheric vertical total electron content (VTEC). Global distribution of VTEC is usually modeled by spherical harmonic expansions, while tensor products of compactly supported univariate B-splines can be used for regional modeling. In these empirical parametric models, the coefficients of the basis functions as well as differential code biases (DCBs) of satellites and receivers can be treated as unknown parameters wh...
Angle of graph energy - A spectral measure of resemblance of isomeric molecules
Gutman, I; Türker, Burhan Lemi (2003-11-01)
A method, elaborated earlier by one of the present authors, for measuring the structural resemblance of isomeric alternant conjugated hydrocarbons, based on a graph-spectral quantity theta, called the angle of total pi-electron energy approach has been extended now to arbitrary molecules. Some general properties of theta have been established.
Near-Earth space plasma modelling and forecasting
Strangeways, Hal J.; Kutiev, Ivan; Cander, Ljiljana R.; Kouris, Stamatis; Gherm, Vadim; Marin, Diego; De La Morena, Benito; Pryse, S. Eleri; Perrone, Loredana; Pietrella, Marco; Stankov, Stanimir; Tomasik, Lukasz; Tulunay, Ersin; Tulunay, Yurdanur; Zernov, Nikolay; Zolesi, Bruno (2009-06-01)
In the frame of the European COST 296 project (Mitigation of Ionospheric Effects oil Radio Systems, MIERS) in the Working Package 1.3, new ionospheric models, prediction and forecasting methods and programs as well as ionospheric imaging techniques have been developed. They include (i) topside ionosphere and meso-scale irregularity models, (ii) improved forecasting methods for real time forecasting and for prediction of foF2, M(3000)F2, MUF and TECs, including the use of new techniques such as Neurofuzzy, N...
Regional VTEC modeling with multivariate adaptive regression splines
Durmaz, Murat; Karslıoğlu, Mahmut Onur; Nohutcu, Metin (Elsevier BV, 2010-07-15)
Different algorithms have been proposed for the modeling of the ionosphere. The most frequently used method is based on the spherical harmonic functions achieving successful results for global modeling but not for the local and regional applications due to the bounded spherical harmonic representation. Irregular data distribution and data gaps cause also difficulties in the global modeling of the ionosphere. In this paper we propose an efficient algorithm with Multivariate Adaptive Regression Splines (MARS)...
Citation Formats
M. Durmaz, “Non-parametric and semi-parametric regional modeling of the ionospheric vertical total electron content using ground-based GPS observations,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.