[G06-P] Poster

[G06-P-08] Ionospheric scintillation detection based on GPS observations, a case study over Iran

Sahar Sobhkhiz¹, Mahdi Alizadeh¹, ^○Michael Schmidt² (1.K.N.Toosi University of Technology, 2.Technical University of Munich)

The earth's upper atmosphere –the ionosphere– is a highly variable region with complex physical structure which is produced by ionizing radiations from the sun. a layer of ionosphere, extended from 250 to 400 km above the earth's surface which contains the greatest amount of free electrons, is called F-region. During strong geomagnetic activities, this region would be disturbed; also small-scale irregularities in electron density would be developed. Signals from Global Positioning System (GPS), pass through this region before reaching receivers on the Earth and therefore if the irregularities are sufficiently enough, signals may experience rapid amplitude fluctuations or unexpected phase changes. This is referred to as ionospheric scintillation. Ionospheric scintillation is one of the dominant propagation disturbances at radio frequency signals. These irregularities severely affect the accuracy and reliability of GPS measurements. Therefore it is necessary to investigate ionospheric scintillation and its effects on GPS observations.
The focus of this paper is to detect ionospheric scintillations over Iran's region, during different periods of solar activity and to investigate these effects on GPS observations in more detail. Furthermore the effects of these irregularities on regional modeling of ionosphere over Iran is also investigated. The results show that effectiveness of this phenomenon depends on geographic location, local time and global geomagnetic storm index (kp index).
The required data for this investigation are ground based measurements of permanent GPS stations over Iran, established by the National Cartographic Center of Iran (NCC).