Ionospheric tomography using GNSS: multiplicative algebraic reconstruction technique applied to the area of Brazil

Abstract

Experimental analysis was performed using multiplicative algebraic reconstruction technique (MART) to map the ionosphere over Brazil. Code and phase observations from the global navigation satellite system (GNSS) together with the international reference ionosphere (IRI) enabled the estimation of ionospheric profiles and total electron content (TEC) over the entire region. Twenty-four days of data collected from existing groundbased GNSS receivers during the recent solar maximum period were used to analyze the performance of the MART algorithm. The results were compared with four ionosondes. It was demonstrated that MART estimated the electron density peak with the same degree of accuracy as the IRI model in regions with appropriate geometrical coverage by GNSS receivers for tomographic reconstruction. In addition, the slant TEC, as estimated with MART, presented lower root-mean-square error than the TEC calculated by ionospheric maps available from the International GNSS Service (IGS). Furthermore, the daily variations of the ionosphere were better represented with the algebraic techniques, compared to the IRI model and IGS maps, enabling a correlation of the elevation of the ionosphere at higher altitudes with the equatorial ionization anomaly intensification. The tomographic representations also enabled the detection of high vertical gradients at the same instants in which ionospheric irregularities were evident.

Spatial and Temporal Features of the Topside Ionospheric Electron Density by a New Model Based On GPS Radio Occultation Data

“…The increasing of the ion production in the upper part of the topside raises the electron density, but no significant variation occurs at the peak height. Consequently, there is a justifiable increasing of H 0 ∕ h. Such event was also indicated in Prol and Camargo (2016) as the main reason that was affecting the estimation of N m by the ionospheric tomography. But at that time, the electron density increasing of topside in the local sunrise was only a speculation that now can be seen thanks to the proposed model based on RO data.…”

Comparative Study of Methods for Calculating Ionospheric Points and Describing the GNSS Signal Path

“…Since it is a simple formulation, low computational efforts are required, which makes it an interesting formulation for many ionospheric systems that requires an intense data process. Das and Shukla (2011) and Prol and Camargo (2016), for example, use such formulation for describing the entire GNSS signal path and performing ionospheric tomographic reconstruction. However, this simplified solution requires a few geometric approximations and, therefore, intrinsic errors in the calculation of the ionospheric points are unavoidable.…”

“…Multiple shell approaches (Komjathy et al, 2002), tomographic algorithms (Mitchell and Spencer, 2003;Wen et al, 2012;Prol and Camargo, 2016;Prol et al, 2017) and data assimilation procedures (Schunk et al, 2004;Hajj et al, 2004;Bust and Mitchell, 2008) are examples of ionospheric modeling algorithms that stratify the ionosphere in many layers. Such algorithms enable analysis of the vertical morphology of the ionosphere and, therefore, give a more complete specification of the ionospheric layers.…”

A new parameterized approach for ionospheric tomography

“…The advent of the global positioning system (GPS) enables tomography to map the 3D IED structures with advantages of high precision, all-weather capability and near-real-time operability (Bust 2004;Zheng et al 2015;Yang et al 2017;Jin and Li 2018). A large amount of significant works thus has been carried out regarding to theoretical models and experimental analysis for GPS-based ionospheric tomography (Ruffini et al 1998;Kersley 2005;Jin and Park 2007;Yao et al 2013a;Alizadeh et al 2015;Minkwitz et al 2015;dos Santos Prol and de Oliveira Camargo 2015;Minkwitz et al 2016).…”