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Investigation of ionospheric pierce points for TNPGN-active network

Authors:

Abstract

In this study, the effects of height of the ionospheric thin shell, neighboring stations and satellite positions on the ionospheric pierce points are investigated by using the data obtained from TNPGN-Active GPS TRIMBLE receivers in Turkey and North Cyprus. For this purpose, Total Electron Content (TEC) value along the path between receiver and satellite, Slant Ray Total Electron Content (STEC) are examined for each satellite and receiver pair. Hence, the data obtained from GPS stations is processed and ionospheric pierce points along the way between receiver and satellite are calculated by considering geographical coordinates of GPS stations. In order to determine the appropriate sampling intervals in the STEC model specific to Turkey, the distance between pierce points are investigated. At the ionospheric heights between 200 km and 450 km, the arc lengths between pierce points are reasonable and proportional to the distance between neighborhoods. Depending on these results, the distance between pierce points represents appropriate sampling intervals for the stations in Turkey.
Investigation of Ionospheric Pierce Points for TNPGN-Active Network and
its Magnetic Conjugate Coordinates
Acknowledgments
Supported by TUBITAK EEEAG 110E296 and RFBR 11-02-91370-CT_a, and
TUBITAK EEEAG 109E055.
Introduction
The effect of ionospheric thin shell height, neighboring
stations and satellite positions on Ionospheric Pierce Points
(IPP) are investigated using TNPGN-Active Network in Turkey,
North Cyprus and Turkey’s magnetic conjugate locations.
Figure 1. SLIM Model
References
1. Arıkan, F., Erol, C. B., and Arıkan, O., ``Regularized estimation of vertical
total electron content from Global Positioning System data '', Journal of
Geophysical Research-Space Physics, 108(A12): 1469-1480, 2003.
2. Arıkan, F., Erol, C. B., and Arıkan, O., ``Regularized estimation of VTEC
from GPS data for a desired time period", Radio Science, 39(6), RS6012,
2004.
Method
Along the path between station and satellite, the points
intersect single layer ionosphere model specified as
ionospheric pierce points. Coordinates of pierce points can be
obtained by solving together line equation passing through
station and satellite, and spherical equation.
Figure 2. Satellites Tracks over ‘igir and ‘cana’
Figure 3. The arc length between pierce points ‘cana’ and ‘igir
stations a) 27 satellite, b) 28 satellite
Conclusion
The arc lengths between IPP are approximately around
100 km at TNPGNActive stations and represent appropriate
sampling intervals. For magnetic conjugate geographic
coordinates, as the distance between pierce points increase,
sampling interval for STEC model increase as well.
Numerical Results
In this study, the ionospheric pierce points are
investigated by using the data obtained from TNPGN Active
GPS stations between the heights of 200 km to 450 km for 144
stations and 32 satellites at time resolution of 30 seconds. The
effect of height, neighboring and satellite position are
investigated in three cases.
Figure 4. The arc length between pierce points at different height
‘cana’ and ‘igir’ stations a) 27 satellite, b) 28 satellite
Figure 5. The arc length between IPP at magnetic conjugates kerg,
‘reun’ and ‘rbay stations a) 27 satellite, b) 28 satellite
Distance between IPP at Magnetic Conjugates
The ionospheric heights between 200 km and 450 km, the
arc length between IPP are proportional to the distance
between neighborhoods at TNPGNActive stations and these
are the treshold values for sampling of the ionosphere which
is the spatial and temporal decorrelation of electron density
profile. Magnetic conjugate stations are single stations.
M. S. Sapaz1, F. Arıkan1, T. Gulyaeva2
Department of Electrical and Electronics Engineering1
Hacettepe University, Ankara, TURKEY1
IZMIRAN Institute 142190, Moscow, RUSSIA2
Key Image 3
Key Image 5
Key Image 4
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‘cana’ all
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satellite
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In this paper a new algorithm for short-term regularized estimation of vertical total electron content (VTEC) from Global Positioning System (GPS) data is developed. The regularization technique can combine signals, from all GPS satellites for a given instant and a given receiver, for a desired time duration within the 24 hour period without missing any important features in the temporal domain. The algorithm is based on the minimization of a cost function which includes a high pass penalty filter and detrend processing. With an optional weighting function the multipath effects are reduced. A final sliding window median filter is added to enrich the processing and smoothing of the data. The developed regularized estimation algorithm is applied to GPS data for various locations for the solar maximum week of 23-28 April 2001. The parameter set that is required by the estimation algorithm is chosen optimally using appropriate error functions. For this data set the chosen robust and optimum parameters can be used for all latitudes and for both quiet and disturbed days for a minimum of one hour time period. It is observed that the estimated TEC values are in very accordance with the TEC estimates for the 24 hour period. Owing to its 30 s time resolution, the regularized VTEC estimates from the developed algorithm are very successful in representation and tracking of sudden temporal variations of the ionosphere, especially for high latitudes and during ionospheric disturbances.
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Sayın, I., Kriging ve Rassal Alan Oncülü ile Toplam Elektron ˙ Iç gi Haritalaması, Yü Lisans Tezi, Hacet-tepë Universitesi, 2008.