Please use this identifier to cite or link to this item: http://nopr.niscair.res.in/handle/123456789/14044
Title: Impact of equatorial ionospheric irregularities on transionospheric satellite links observed from a low-latitude station during the minima of solar cycle 24
Authors: Das, T
Roy, B
Gupta, A Das
Paul, A
Keywords: Equatorial ionospheric irregularities
Transionospheric communication
Carrier-to-noise (CNO) ratio
Position dilution of precision (PDOP)
Equatorial electrojet (EEJ) strength
Slant total electron content (STEC)
Issue Date: Apr-2012
Publisher: NISCAIR-CSIR, India
Abstract: Effects of equatorial ionization density irregularities on transionospheric communication and navigation links have been studied during the abnormally prolonged minima of the 24th solar cycle from Calcutta, a station situated virtually underneath the northern crest of the equatorial ionization anomaly in the Indian longitude sector. Scintillations at L-band have been sparse during 2008-2010 with four cases of GPS scintillations being observed from Calcutta. It is interesting to note that all these cases of scintillations were observed when the irregularities were field-aligned. One of the cases occurred on 25 September 2008 when GPS SV12 link exhibited depletions in TEC of nearly 8 TEC units around 15:30 hrs UTC associated with fluctuations in carrier-to-noise (CNO) ratio at L1 frequency and position dilution of precision (PDOP). The 1-min S4 index reached a maximum value of 0.48 [SI~11dB] on the SV12 link around 15:30 hrs UT. The geostationary FLEETSATCOM link at 250 MHz was also disrupted during the period 15:55-16:25 hrs UT with maximum S4 of 0.69 [SI~17dB]. The ambient ionization and strength of the equatorial electrojet was higher on that day than other days around that period. The F-region height rise around sunset was significant as indicated by a flat-topped ionization density distribution over the magnetic equator by Defense Meteorological Satellite Program (DMSP).
Description: 247-257
URI: http://hdl.handle.net/123456789/14044
ISSN: 0975-105X (Online); 0367-8393 (Print)
Appears in Collections:IJRSP Vol.41(2) [April 2012]

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