Total Electron Content Estimation with Reg‐Est

Abstract

[1] Total Electron Content (TEC) constitutes one of the key elements for observing the variable structure of the ionosphere. GPS provides a cost-effective alternative in TEC estimation through earth-based receivers. In this paper, one of the TEC estimation methods, namely Reg-Est, is investigated in detail in terms of its parameters and developed further to include improvements. Reg-Est estimates robust TEC using GPS measurements of 30 s time resolution. The method combines the vertical TEC computed from all the satellites in view over 10°horizon limit in the least squares sense through the minimization of a cost function which also includes a high pass penalty filter. Optional weighting functions and sliding window median filters are added to enrich the processing and smoothing of the data. In this study, the input to the Reg-Est is enlarged to include phase-corrected TEC. The best way of including the instrumental biases is investigated and the algorithm is updated to include the biases in the slant TEC computation. The effect of the thin shell height of the ionosphere in Reg-Est estimates is studied. It is concluded that the Reg-Est algorithm is very robust to the choice of thin shell height. The best weighting function to reduce the multipath effects and to minimize the non-ionospheric noise is selected. The improved Reg-Est algorithm can be used for all latitudes and for both quite and disturbed days of the ionosphere. The Reg-Est TEC are in excellent accordance with the estimates from IGS analysis centers.

Tomographic reconstruction of the ionospheric electron density as a function of space and time

“…The list of these receivers and their coordinates are also provided in Table 1. The STEC from the GPS receivers are obtained using Reg-Est and Ionolab-TEC as discussed in detail in Nayir et al (2007) and y in Eq. 18 is formed.…”

“…In a study conducted by Arikan et al (2003), regularized estimation of vertical total electron content from Global Positioning System data is researched and a new method is proposed. The GPS data used in this study is obtained by the developed Reg-Est method discussed in Nayir et al (2007) and IONOLAB using the phase delay measurements.…”

Optimization of F2 layer parameters using IRI-Plas model and IONOLAB Total Electron Content

“…In this study, GPS-TEC data is obtained from www.ionolab.org as IONOLAB-TEC [4][5][6]. IONOLAB-TEC combines data from all the GPS satellites that are above 10 o elevation angle (horizon limit) of the GPS station with a temporal resolution of 30 seconds.…”

“…IONOLAB-TEC combines data from all the GPS satellites that are above 10 o elevation angle (horizon limit) of the GPS station with a temporal resolution of 30 seconds. The method calculates VTEC (Vertical Total Electron Content) per satellite and combines them using a weighting function based on satellite positions which reduces the contamination caused by multipath effects [5][6]. The receiver differential code bias are estimated using the method described in [4].…”

“…In IRI-Plas, TEC estimates can be provided externally for scaling of topside and plasmasphere extensions. In this study, GPS-TEC is obtained as IONOLAB-TEC [4][5] and provided externally for scaling of F2 layer parameters. The goal of this study is to update IRI-Plas with IONOLAB-TEC in an iterative optimization loop by also including the physical correlations between IRI parameters formed by Non-Linear Least Squares method, and also to obtain more realistic IRI-Plas outputs for TEC and ionosphere electrical and ionic structure estimates by this way.…”