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A study of equatorial plasma bubble structure using VHF radar and GNSS scintillations over the low-latitude regions
(2022-10-01)
Bumrungkit, Acharaporn
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Supnithi, Pornchai
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Saito, Susumu
;
Myint, Lin Min Min
Ionospheric irregularities can cause detrimental effects on the global navigation satellite system (GNSS) signals, often in the form of rapid fluctuations in both amplitude and phase. Over the low-latitude regions, the equatorial plasma bubble (EPB) frequently arises after sunset, leading to GNSS scintillations since the signals propagate through ionospheric irregularities. The relationship between amplitude ionospheric scintillations (S4 index) on GNSS signals and EPB characteristics is presented. We investigate the geometrical relationship between backscatter echoes associated with the EPB and the multi-constellation and multi-frequency scintillations, specifically, GPS and Galileo constellations with L1/E1 and L5/E5a signals. By analyzing the GNSS scintillations along the GNSS signal paths, the GNSS ionospheric pierce points (IPPs) are mapped with S4 index at different altitudes and projected along the magnetic field line together with the backscatter echoes at the equatorial atmosphere radar (EAR), West Sumatra, Indonesia. Our results are obtained for moderate scintillation cases due to limited data available for this study. The results show the EPB impact ionospheric scintillations. The S4 index on the L5/E5a signal is more susceptible to scintillations than the L1/E1 signal. Moreover, we found a high correlation between EAR backscatter echoes and S4 values on both L1/E1 and L5/E5a at an altitude between 250 and 350 km, indicating that the EPB occurs on the bottomside of the ionosphere.
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Preliminary results of EPB impact on GBAS performance
(2019-06-01)
Bumrungkit, Acharaporn
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Phakphisut, Watid
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Supnithi, Pornchai
In the low-latitude region, equatorial plasma bubbles (EPBs) frequently occur. Ionospheric irregularity due to EPBs can degrade the performance of ground-based augmentation system (GBAS) in aviation. This work focuses on the impact of multiple EPBs on GBAS performance. The multiple EPBs with varied separation distances are simulated to assess the performance of GBAS in Thailand. From the simulation, the results show that the 100 km separation distance causes a more hazardous error in vertical than 1200 km separation distance between the EPBs.
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Statistical Analysis of Separation Distance Between Equatorial Plasma Bubbles Near Suvarnabhumi International Airport, Thailand
(2018-09-01)
Bumrungkit, Acharaporn
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Supnithi, Pornchai
;
Saito, Susumu
Ionospheric disturbances can lead to the major detrimental effects on the availability of ground-based augmentation system. In low-latitude regions, equatorial plasma bubbles (EPBs) frequently arise. They originated from the bottom side of the ionosphere with the electron density inside the plasma bubbles lower than the outside area. It is well known that the EPB causes the strong fluctuation on Global Positioning System signals when passing through the ionospheric disturbed regions. Sometimes the EPBs may have more than one front. To better understand the ionospheric anomaly effect on ground-based augmentation system efficiency, the separation distance between EPBs needs to be studied. In this work, we analyze the slant total electron content from dual-frequency Global Positioning System receivers near Suvarnabhumi International Airport, Thailand, to ascertain the EPB occurrence. The distance between observed EPBs is computed based on the Haversine formula technique. The results found that the estimated separation distances between depletions on disturbed days in 2015 are in the range of 100 to 1,200 km.
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Statistical Analysis of Separation Distance between Equatorial Plasma Bubbles
(2017-05-17)
Bumrungkit, Acharaporn
;
Supnithi, Pornchai
Equatorial plasma bubbles in the low-latitude regions can cause loss-of-lock resulting to the availability of ground-based augmentation system (GBAS) due to increased ionospheric gradients. For realistic simulation, distances between adjacent bubbles need to be determined. In this study, we analyze the statistics of this parameter around the Suvarnabhumi international airport, Thailand. This work presents the methodology to estimate the separation distance between visible plasma bubbles on the same day. To detect the equatorial plasma bubbles, we analyze the slant total electron content (STEC), which is obtained from the dual-frequency GNSS receiver located at King Mongkut's Institute of Technology Ladkrabang (geographic, 13.7278o N, 100.7726o E). The results show that the separation distance between plasma bubbles on anomalous ionosphere are in range of 30 to 150 kilometers.
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Drift velocity estimation of ionospheric disturbance using GPS observations
(2014-01-01)
Bumrungkit, Acharaporn
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Rungraengwajiake, Sarawoot
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Supnithi, Pornchai
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Siansawasdi, Nattapong
The Ground-Based Augmentation System (GBAS) based on the global positioning system (GPS) is used for positioning accuracy improvement of the aircraft landing. However, the ionospheric irregularity can cause irregular electron density that affects the accuracy of GBAS system. In this work, we analyze the drift velocity of ionospheric irregularity or plasma bubble phenomenon by using the correlation time of slant total electron content (STEC) from two GPS receivers that are located near Suvarnabhumi airport, Thailand. The data on September 1<sup>st</sup>, 2011 with the plasma bubble occurrence is analyzed. The result shows the drift velocity of plasma bubbles is about 108 meterspersecond (m/s). © 2014 IEEE.

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