Mohammed Mainul Hoque

TL;DR: In this article, the authors proposed a non-linear approach for determining global TEC, which requires only 12 coefficients and a few empirically fixed parameters for describing the broad spectrum of TEC variation at all levels of solar activity, and applied it on high-quality global ionosphere data derived by the Center for Orbit Determination in Europe at the University of Berne over more than half a solar cycle (1998-2007).

TL;DR: The Neustrelitz TEC Model (NTCM) as mentioned in this paper is a basic approach for a family of regional and a global TEC models, which can be used for reconstructing reliable TEC maps distributed via an operational space weather and ionosphere data service.

TL;DR: In this article, a simple formula has been derived for GNSS users in Germany to quantify the second-order residual effect, and a proposed correction algorithm reduces the secondorder effects to a residual error of fractions of 1 mm up to 2 mm at a vertical total electron content level of 1018 electrons/m2, depending on satellite azimuth and elevation angles.

TL;DR: In this paper, four ionospheric models based on GNSS data (the Electron Density Assimilative Model, EDAM; the Ionosphere Monitoring Facility, IONMON v2; the Tomographic Ionosphere model, TOMION; and the Neustrelitz TEC Models, NTCM) have been run using a controlled set of input data.

TL;DR: In this paper, a rigorous treatment of these problems is presented, and different approximation formulas have been proposed to correct errors due to excess path length in addition to the free space path length, TEC difference at two GNSS frequencies, and third-order ionospheric term.