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International Reference Ionosphere (IRI) is the most commonly used climatic model of ionosphere. Recently developed IRI Extended to Plasmasphere (IRI-Plas) model extended the interest region of IRI to the GPS orbital height of 20,000 km. IRI-Plas can not only input F2 layer critical frequency, foF2, and maximum ionization height, hmF2, similar to IRI but also it can update and scale foF2 with the...
Ionosphere is an atmospheric layer that has a high electron concentration and anisotropic, dispersive, inhomogeneous nature. Total Electron Content (TEC) is one of the most important parameters that provides necessary information to observe the ionospheric variability. In this study, spatial-temporal variability of the ionosphere is investigated using Symmetric Kullback Leibler Distance (SKLD), Metric...
IONOLAB is an interdisciplinary research group dedicated for handling the challenges of near earth environment on communication, positioning and remote sensing systems. IONOLAB group contributes to the space weather studies by developing state-of-the-art analysis and imaging techniques. On the website of IONOLAB group, www.ionolab.org, four unique space weather services, namely, IONOLAB-TEC, IRI-PLAS-2015,...
In this study, research activities of IONOLAB group on remote sensing and 2-D imaging of ionosphere in the last 10 years will be summarized. In TUBITAK EEEAG 105E171 and 109E055 projects, a novel Total Electron Content (TEC) estimation method, IONOLAB-TEC, is developed using the dual frequency Global Positioning System (GPS) pseudo range and phase delay recordings. The IONOLAB-TEC computation is provided...
Ionosphere, which plays an important role in both High Frequency and satellite communication, can be described by Total Electron Content (TEC), and critical layer parameters in frequency (fo) and peak height (hm). International Reference Ionosphere Extended to Plasmasphere (IRI-Plas), is a convenient empirical deterministic model of ionosphere and plasmasphere. In this study, IRI-Plas is modified...
Ionosphere plays an important role in High Frequency (HF) communications. In this paper, Global Ionospheric Maps (GIM) of Total Electron Content (TEC), maximum ionization height (hmF2) and critical frequency (foF2) of F2-layer are presented. These maps are obtained from the Nonlinear Least Squares (NLSQ) optimization of the International Reference Ionosphere (IRI) model extended to the Plasmasphere...
-layer is the most important and characteristic layer of the ionosphere in the propagation of high frequency (HF) waves due to the highest level of conductivity in the propagation path. In this study, the relation of Total Electron Content (TEC) with the maximum ionization height and the critical frequency of -layer are investigated within their defined parametric range using...
In this study, the relation of the maximum ionization height (HmF2) and the critical frequency (FoF2) of F2 layer is examined within their parametric range through the International Reference Ionosphere extended towards the plasmasphere (IRI-Plas) model and the IONOLAB-TEC. HmF2 and FoF2 are optimized using an iterational loop through Non-Linear Least Squares method. HmF2 and FoF2 are obtained for...
Turkish National Permanent GPS Network (TNPGN) is the Reference Station Network of 146 continuously-operating GNSS stations o which are distributed uniformly across Turkey and North Cyprus Turkish Republic since May 2009. IONOLAB group, formed by researchers and students in Hacettepe University, Bilkent University and General Command of Mapping is currently investigating new techniques for space-time...
Characterization and constant monitoring of variability of the ionosphere is of utmost importance for the performance improvement of HF communication, Satellite communication, navigation and guidance systems, Low Earth Orbit (LEO) satellite systems, Space Craft exit and entry into the atmosphere and space weather. Turkish National Permanent GPS Network (TNPGN) is the Reference Station Network of 146...
In this study, the relation of the maximum ionization height (HmF2) and the critical frequency (FoF2) of F2 layer is examined within their parametric range through the International Reference Ionosphere extended towards the plasmasphere (IRI-Plas) model and the IONOLAB-TEC (Total Electron Content) observations. HmF2 and FoF2 are optimized using an iterational loop through Non-Linear Least Squares...
We know that F2 layer of the ionosphere is most important layer in the progaration of high frequency (HF) waves. In this study, The relation of the height (HmF2) and the critical frequency (FoF2) of F2 layer—among the parameters of the Internation Reference Ionesphere (IRI) model—to the Total Electron Content (TEC) structure of ionosphere is investigated within their defined parametric range. These...
Shadow can cause problems for image processing algorithms like object tracking and image segmentation. It is observed that, whenever a target enters a shadowed area, object tracking algorithms fail. To overcome that kind of problems, various methods are produced to find and remove shadows on images. In this paper a different model, which compensate both contrast and illumination for shadows, is developed...
Because of the effects on radio waves, monitoring the ionosphere gains significant importance. Monitoring of the ionosphere becomes possible by estimating Total Electron Content (TEC) which is the major variable expressing ionospheric effects. Although International Reference Ionosphere (IRI) and International GNSS Service (IGS) analysis centers can generate TEC estimates, these estimates either have...
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