scholarly journals Analysis of the Relationship between Scintillation Parameters, Multipath and ROTI

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2877
Author(s):  
Chendong Li ◽  
Craig M. Hancock ◽  
Nicholas A. S. Hamm ◽  
Sreeja V. Veettil ◽  
Chong You
Keyword(s):  
Structural Similarity ◽  
Sampling Interval ◽  
Rate Of Change ◽  
Scintillation Index ◽  
Ionospheric Scintillation ◽  
Electron Content ◽  
Total Electron ◽  
Two Indices ◽  
The Relationship ◽  
Scintillation Indices

Global Navigation Satellite System (GNSS) operation can be affected by several environmental factors, of which ionospheric scintillation is one of the most significant. Scintillation is usually characterized by two indices, namely the amplitude scintillation index (S4) and phase scintillation index (σφ). However, these two indices can only be generated by specialized GNSS receivers, which are not widely available all around the world. To popularize the study of scintillation, this article proposes to use more accessible parameters, namely multipath (MP) and rate of change of total electron content index (ROTI), to characterize scintillation. Using GPS data obtained on six days in total from three stations, namely PRU2 and SAO0P located in Sao Paulo, Brazil and SNA0P located in Antarctica, respectively, both the time series plots and 2D maps were generated to investigate the relationship of scintillation indices (S4 and σφ) with MP and ROTI. To prevent the effect of the real multipath error, a 30-degree satellite elevation mask is applied to all the data. As the scintillation indices S4 and σφ have a sampling interval of 1 min, MP and ROTI are calculated with the same sampling interval for a more direct comparison. The results show that the structural similarity (SSIM) and correlation coefficient (CC) between parameters was greater than 0.7 for 70% of outputs. In addition, the variogram and cross-variogram are applied to investigate the spatial structure of the MP, ROTI, S4 and σφ in order to support the results of SSIM and CC. With outputs in three forms, promising spatial and temporal relationships between parameters was observed.

scholarly journals An interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite

2013 ◽  
Vol 56 (2) ◽  
Author(s):  
Paul Prikryl ◽  
Yongliang Zhang ◽  
Yusuke Ebihara ◽  
Reza Ghoddousi-Fard ◽  
Periyadan T. Jayachandran ◽  
...  
Keyword(s):  
High Speed ◽  
The Arctic ◽  
Scintillation Index ◽  
Ionospheric Scintillation ◽  
Electron Content ◽  
South Pole ◽  
The South ◽  
Total Electron ◽  
Auroral Emission ◽  
Sky Imager

<p>The global positioning system (GPS) phase scintillation caused by high-latitude ionospheric irregularities during an intense high-speed stream (HSS) of the solar wind from April 29 to May 5, 2011, was observed using arrays of GPS ionospheric scintillation and total electron content monitors in the Arctic and Antarctica. The one-minute phase-scintillation index derived from the data sampled at 50 Hz was complemented by a proxy index (delta phase rate) obtained from 1-Hz GPS data. The scintillation occurrence coincided with the aurora borealis and aurora australis observed by an all-sky imager at the South Pole, and by special sensor ultraviolet scanning imagers on board satellites of the Defense Meteorological Satellites Program. The South Pole (SP) station is approximately conjugate with two Canadian High Arctic Ionospheric Network stations on Baffin Island, Canada, which provided the opportunity to study magnetic conjugacy of scintillation with support of riometers and magnetometers. The GPS ionospheric pierce points were mapped at their actual or conjugate locations, along with the auroral emission over the South Pole, assuming an altitude of 120 km. As the aurora brightened and/or drifted across the field of view of the all-sky imager, sequences of scintillation events were observed that indicated conjugate auroras as a locator of simultaneous or delayed bipolar scintillation events. In spite of the greater scintillation intensity in the auroral oval, where phase scintillation sometimes exceeded 1 radian during the auroral break-up and substorms, the percentage occurrence of moderate scintillation was highest in the cusp. Interhemispheric comparisons of bipolar scintillation maps show that the scintillation occurrence is significantly higher in the southern cusp and polar cap.</p>

TEC and Scintillations in the Ionosphere above Greenland

2021 ◽  
Author(s):  
Sarah Beeck ◽  
Anna Jensen ◽  
Per Knudsen
Keyword(s):  
Real Time ◽  
Spatial Data ◽  
The Arctic ◽  
Scintillation Index ◽  
Ionospheric Scintillation ◽  
Electron Content ◽  
Real Time Monitoring ◽  
Total Electron ◽  
Cycle Slips ◽  
Natural Neighbor

&lt;p&gt;Global Navigation Satellite System (GNSS) signals are affected by the media of the ionosphere when traversing it. Therefore, near real-time monitoring of the ionosphere and its scintillation can be an advantage for GNSS users. There can be strong phase scintillation in the Arctic region, however, there is no continuous real-time monitoring of the ionosphere above Greenland at the moment. This project investigates possibilities for real-time monitoring of the ionosphere above Greenland, based on data from geodetic GNSS stations. The novelty of the work is the application of the kriging method as basis for rate of total electron content index (ROTI) maps in the Arctic.&lt;/p&gt;&lt;p&gt;The GNSS data analyzed in this project is from seven selected GNSS receivers that are part of the Greenland GPS Network (GNET). The data is used for computing the phase scintillation index ROTI, which is then used for mapping the scintillation activity. First the spatial data coverage was examined to investigate the possibility of visualizing the ROTI values spatially. Further, the kriging and natural neighbor methods were tested for interpolating ROTI above Greenland.&lt;/p&gt;&lt;p&gt;In the project there were some large spatial data gaps, caused by the sparse distribution of the GNSS receiver stations. A relation between high ROTI values and low elevation angles was shown, and this relation was more prominent at geomagnetically quiet times. This indicated that a higher elevation cut-off angle might have been useful for the mapping if more data had been available. The test of the interpolation methods lead to the conclusion that kriging provided slightly better maps than the natural neighbor method at geomagnetically active times, while natural neighbor might be preferable at geomagnetically quiet times. Finally, it was found that receivers at all of the tested latitudes were affected by ionospheric phase scintillation, this was seen as an increase in the amount of cycle slips.&lt;/p&gt;&lt;p&gt;The conclusions drawn from this project can help indicate what the next step should be on the path towards real-time monitoring the ionosphere above Greenland. The general recommendation for future work is to install a network of GNSS Ionospheric Scintillation and TEC Monitor (GISTM) receivers in Greenland which can provide near real-time scintillation indices.&lt;/p&gt;

scholarly journals New observations of the total electron content and ionospheric scintillations over Ho Chi Minh City

2020 ◽  
Vol 42 (4) ◽  
Author(s):  
Tam Dao ◽  
Minh Le Huy ◽  
Brett Carter ◽  
Que Le ◽  
Thanh Thuy Trinh ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Rate Of Change ◽  
Ho Chi Minh City ◽  
Ionospheric Scintillation ◽  
Phase Method ◽  
Small Scale ◽  
Electron Content ◽  
Total Electron ◽  
Gnss Receiver ◽  
Ionospheric Scintillations

In January 2018, a Trimble NetR9 GNSS receiver was installed at International University - Vietnam National University (IU-VNU), which is located at 10°52'N, 106°48'E in Ho Chi Minh City (HCMC). The GNSS signals recorded from the receiver are useful for studying the ionospheric variations over this station as well as the magnetosphere-ionosphere coupling effects, therefore, we aim to preliminarily process and evaluate data recorded from this new station. Based on the data obtained with this GNSS receiver, we first estimated the total electron content (TEC) using the carrier-phase method which is a combination of code and phase measurements. We then calculated the rate of change of TEC index (ROTI) with respect to time and investigated its day-to-day variations. Our results show some typical features in the diurnal and seasonal TEC and ionospheric scintillation variations during 2018-2019. The distributions of ROTI over these two years of solar minimum show significant occurrences of scintillation, which are caused by small-scale ionospheric irregularities in the equatorial ionosphere. In addition, we found a significant increase of TEC in the latest strong geomagnetic storm in August 2018. The disturbance dynamo appears to have suppressed plasma bubbles after sunset and enhanced their formation at midnight. Thus, the disturbance dynamo effectively caused a delay of ionospheric scintillations. The TEC observed in HCMC also contributes to the data of ground-based observational receiver systems along 105o E longitude for studying ionospheric variations in low-latitude and equatorial regions. Our preliminary results indicate that the GNSS data collected at IU-VNU station is a valuable reference dataset for further research of the ionosphere.

scholarly journals Multi-Scale Ionospheric Anomalies Monitoring and Spatio-Temporal Analysis during Intense Storm

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 215
Author(s):  
Na Cheng ◽  
Shuli Song ◽  
Wei Li
Keyword(s):  
Magnetic Storm ◽  
Large Scale ◽  
Temporal Dynamics ◽  
Ionospheric Disturbance ◽  
Ionospheric Scintillation ◽  
Small Scale ◽  
Electron Content ◽  
Total Electron ◽  
Multi Scale ◽  
Intense Storm

The ionosphere is a significant component of the geospace environment. Storm-induced ionospheric anomalies severely affect the performance of Global Navigation Satellite System (GNSS) Positioning, Navigation, and Timing (PNT) and human space activities, e.g., the Earth observation, deep space exploration, and space weather monitoring and prediction. In this study, we present and discuss the multi-scale ionospheric anomalies monitoring over China using the GNSS observations from the Crustal Movement Observation Network of China (CMONOC) during the 2015 St. Patrick’s Day storm. Total Electron Content (TEC), Ionospheric Electron Density (IED), and the ionospheric disturbance index are used to monitor the storm-induced ionospheric anomalies. This study finally reveals the occurrence of the large-scale ionospheric storms and small-scale ionospheric scintillation during the storm. The results show that this magnetic storm was accompanied by a positive phase and a negative phase ionospheric storm. At the beginning of the main phase of the magnetic storm, both TEC and IED were significantly enhanced. There was long-duration depletion in the topside ionospheric TEC during the recovery phase of the storm. This study also reveals the response and variations in regional ionosphere scintillation. The Rate of the TEC Index (ROTI) was exploited to investigate the ionospheric scintillation and compared with the temporal dynamics of vertical TEC. The analysis of the ROTI proved these storm-induced TEC depletions, which suppressed the occurrence of the ionospheric scintillation. To improve the spatial resolution for ionospheric anomalies monitoring, the regional Three-Dimensional (3D) ionospheric model is reconstructed by the Computerized Ionospheric Tomography (CIT) technique. The spatial-temporal dynamics of ionospheric anomalies during the severe geomagnetic storm was reflected in detail. The IED varied with latitude and altitude dramatically; the maximum IED decreased, and the area where IEDs were maximum moved southward.

Implications of Ionospheric Scintillation for GNSS Users in Northern Europe

2005 ◽  
Vol 58 (2) ◽  
pp. 241-256 ◽  
Author(s):  
Marcio Aquino ◽  
Terry Moore ◽  
Alan Dodson ◽  
Sam Waugh ◽  
Jock Souter ◽  
...  
Keyword(s):  
Northern Europe ◽  
Ionospheric Scintillation ◽  
Electron Content ◽  
Total Electron ◽  
Northern European ◽  
Amplitude Fluctuations ◽  
The Uk ◽  
Time Delay Effect ◽  
Electron Density Irregularities ◽  
The Impact

Extensive ionospheric scintillation and Total Electron Content (TEC) data were collected by the Institute of Engineering Surveying and Space Geodesy (IESSG) in Northern Europe during years of great impact of the solar maximum on GNSS users (2001–2003). The ionospheric TEC is responsible for range errors due to its time delay effect on transionospheric signals. Electron density irregularities in the ionosphere, occurring frequently during these years, are responsible for (phase and amplitude) fluctuations on GNSS signals, known as ionospheric scintillation. Since June 2001 four GPS Ionospheric Scintillation and TEC Monitor receivers (the NovAtel/AJ Systems GSV4004) have been deployed at stations in the UK and Norway, forming a Northern European network, covering geographic latitudes from 53° to 70° N approximately. These receivers compute and record GPS phase and amplitude scintillation parameters, as well as TEC and TEC variations. The project involved setting up the network and developing automated archiving and data analysis strategies, aiming to study the impact of scintillation on DGPS and EGNOS users, and on different GPS receiver technologies. In order to characterise scintillation and TEC variations over Northern Europe, as well as investigate correlation with geomagnetic activity, long-term statistical analyses were also produced. This paper summarises our findings, providing an overview of the potential implications of ionospheric scintillation for the GNSS user in Northern Europe.

scholarly journals RESPON TEC IONOSFER DI ATAS BANDUNG DAN MANADO TERKAIT FLARE SINAR-X MATAHARI KELAS M5.1 DAN M7.9 TAHUN 2015 (IONOSPHERIC TEC RESPONSE OVER BANDUNG DAN MANADO ASSOCIATED WITH M5.1 AND M7.9 CLASSES OF SOLAR FLARE XRAYS IN 2015)

2018 ◽  
Vol 14 (2) ◽  
pp. 111
Author(s):  
Sri Ekawati
Keyword(s):  
Time Delay ◽  
Solar Flare ◽  
Electron Density ◽  
Total Electron Content ◽  
Geomagnetic Latitude ◽  
Ionospheric Scintillation ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
X Rays ◽  
Total Electron

The solar flare is potential to cause sudden increase of the electron density in the ionosphere,particularly in D layer, known as Sudden Ionospheric Disturbances (SID). This increase of electron density occurs not only in the ionospheric D layer but also in the ionospheric E and F layers. Total Electron Content (TEC) measured by GPS is the total number of electrons from D to F layer. The aim of this research is to study the effect of solar flare x-rays, greater than M5 class in 2015, on ionospheric TEC over Bandung and Manado. This paper presents the preliminary result of ionospheric TEC response on solar flare occurrence over Indonesia. The ionospheric TEC data is derived from GPS Ionospheric Scintillation and TEC Monitor (GISTM) receiver at Bandung (-6.90o S;107.6o E geomagnetic latitude 16.54o S) and Manado (1.48o N; 124.85o E geomagnetic latitude 7.7o S). The solar x-rays flares classes analyzed where M5.1 on 10 March 2015 and M7.9 on 25 June 2015. Slant TEC (STEC) values where calculated to obtain Vertical TEC (VTEC) and the Differential of the VTEC (DVTEC) per PRN satellite for further analysis. The results showed that immediately after the flare, there where sudden enhancement of the VTEC and the DVTEC (over Bandung and Manado) at the same time. The time delay of ionospheric TEC response on M5.1 flare was approximately 2 minutes, then the VTEC increased by 0.5 TECU and the DVTEC rose sharply by 0.5 – 0.6 TECU/minutes. Moreover, the time delay after the M7.9 flare was approximately 11 minutes, then the VTEC increased by 1 TECU and the DVTEC rose sharply by 0.6 – 0.9 TECU/minutes. ABSTRAK Flare matahari berpotensi meningkatkan kerapatan elektron ionosfer secara mendadak, khususnya di lapisan D, yang dikenal sebagai Sudden Ionospheric Disturbances (SID). Peningkatan kerapatan elektron tersebut terjadi tidak hanya di lapisan D, tetapi juga di lapisan E dan F ionosfer. Total Electron Content (TEC) dari GPS merupakan jumlah banyaknya elektron total dari lapisan D sampai lapisan F. Penelitian ini bertujuan mengetahui efek flare, yang lebih besar dari kelas M5 tahun 2015, terhadap TEC ionosfer di atas Bandung dan Manado. Makalah ini merupakan hasil awal dari respon TEC ionosfer terhadap fenomena flare di atas Indonesia. Data TEC ionosfer diperoleh dari penerima GPS Ionospheric Scintillation and TEC Monitor (GISTM) di Bandung (-6,90o S; 107,60o E lintang geomagnet 16,54o LS) dan Manado (1,48oLU;124,85oBT lintang geomagnet 7,7o LS) dikaitkan dengan kejadian flare kelas M5.1 pada tanggal 10 Maret 2015 dan kelas M7.9 pada tanggal 25 Juni 2015. Nilai Slant TEC (STEC) dihitung untuk memperoleh nilai Vertical TEC (VTEC), kemudian nilai Differential of VTEC (DVTEC) per PRN satelit diperoleh untuk analisis selanjutnya. Hasil menunjukkan segera setelah terjadi flare, terjadi peningkatan VTEC dan DVTEC (di atas Bandung dan Manado) secara mendadak pada waktu yang sama. Waktu tunda dari respon TEC ionosfer setelah terjadi flare M5.1 adalah sekitar 2 menit, kemudian VTEC meningkat sebesar 0,5 TECU dan DVTEC meningkat secara tajam sebesar 0,5 – 0,6 TECU/menit. Sedangkan, waktu tunda setelah terjadi flare M7.9 adalah 11 menit, kemudian VTEC meningkat sebesar 1 TECU dan DVTEC meningkat secara tajam sebesar 0,6 – 0,9 TECU/menit.

scholarly journals Characterization of ionospheric irregularities over Vietnam and adjacent region for the 2008-2018 period

2021 ◽  
Author(s):  
Dung Nguyen Thanh ◽  
Minh Le Huy ◽  
Christine Amory-Mazaudier ◽  
Rolland Fleury ◽  
Susumu Saito ◽  
...  
Keyword(s):  
Solar Activity ◽  
Correlation Coefficients ◽  
Rate Of Change ◽  
Occurrence Rate ◽  
High Solar Activity ◽  
Electron Content ◽  
Total Electron ◽  
Plasma Irregularities ◽  
Almost All ◽  
Continuous Gps

This paper presents the variations of the rate of change of Total Electron Content (TEC) index (ROTI), characterizing the occurrence of ionospheric plasma irregularities over Vietnam and neighboring countries in the Southeast Asian region using the continuous GPS data during the 2008-2018 period. The results showed that the occurrence of strong ROTI in all stations is maximum in equinox months March/April and September/October and depends on solar activity. The ROTI is weak during periods of low solar activity and strong during periods of high solar activity. There is an asymmetry between the two equinoxes. During maximum and declining phases of 2014-2016, occurrence rates in March equinox are larger than in September equinox, but during the descending period of 2010-2011, the occurrence rates in September equinox at almost all stations are larger than in March equinox. The correlation coefficients between the monthly occurrence rate of irregularities and the F10.7 solar index at the stations in the equatorward EIA crest region are higher than at those in the magnetic equatorial and the poleward EIA crest regions. The irregularity occurrence is high in the pre-midnight sector, maximum between 2000 LT to 2200 LT. The maximum irregularity occurrence is located around 4-5° degrees in latitude equator-ward away from the anomaly crests.

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