scholarly journals Properties and Generation of Large Scale Travelling Ionospheric Disturbances during 8 September 2017

2020 ◽  
Author(s):  
Claudia Borries ◽  
Arthur Amaral Ferreira ◽  
Chao Xiong ◽  
Renato Alves Borges ◽  
Jens Mielich ◽  
...  
Keyword(s):  
Large Scale ◽  
Satellite System ◽  
Auroral Oval ◽  
Ionospheric Disturbances ◽  
High Latitudes ◽  
Travelling Ionospheric Disturbances ◽  
Source Mechanisms ◽  
Magnetometer Data ◽  
Space Weather Event ◽  
Global Navigation Satellite

<p>Large Scale Travelling Ionospheric Disturbances (LSTIDs) are a frequent phenomenon during ionospheric storms, indicating strong electrodynamic processes in high latitudes. LSTIDs are signatures of Atmospheric Gravity Waves (AGW) observed in the changes of the electron density in the ionosphere. During ionospheric storms, large scale AGWs are often generated in the vicinity of the auroral region, where sudden strong heating processes take place.</p><p>Many LSTIDs are observed during the ionosphere storm during the September 2017 Space Weather event. In this presentation, the LSTID occurrence on 8<sup>th</sup> September 2017 is analysed in more detail, based on a TID detection method using ground based Global Navigation Satellite System (GNSS) measurements. Fast LSTIDs are observed in midlatitudes between 0-3 UT and 13-16 UT. Slow LSTIDs are observed between 3-12 UT. A significant strong wave-like TEC perturbation occurred in high latitudes at noon, which vanished at around 50°N. A strong single LSTID in mid-latitudes generated in high latitudes around 18 UT. Consulting IMAGE magnetometer data, ionosonde measurements and Swarm field aligned current measurements, strong heating processes, the extension of the Auroral oval and unusual electrodynamic processes are discussed as source mechanisms for these LSTIDs.</p>

scholarly journals An overview of methodologies for real-time detection, characterisation and tracking of traveling ionospheric disturbances developed in the TechTIDE project

2020 ◽  
Vol 10 ◽  
pp. 42
Author(s):  
Anna Belehaki ◽  
Ioanna Tsagouri ◽  
David Altadill ◽  
Estefania Blanch ◽  
Claudia Borries ◽  
...  
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Tracking System ◽  
Warning System ◽  
Satellite System ◽  
Ionospheric Disturbances ◽  
Time Activity ◽  
Travelling Ionospheric Disturbances ◽  
Additional Information ◽  
Global Navigation Satellite

The main objective of the TechTIDE project (warning and mitigation technologies for travelling ionospheric disturbances effects) is the development of an identification and tracking system for travelling ionospheric disturbances (TIDs) which will issue warnings of electron density perturbations over large world regions. The TechTIDE project has put in operation a real-time warning system that provides the results of complementary TID detection methodologies and many potential drivers to help users assess the risks and develop mitigation techniques tailored to their applications. The TechTIDE methodologies are able to detect in real time activity caused by both large-scale and medium-scale TIDs and characterize background conditions and external drivers, as an additional information required by the users to assess the criticality of the ongoing disturbances in real time. TechTIDE methodologies are based on the exploitation of data collected in real time from Digisondes, Global Navigation Satellite System (GNSS) receivers and Continuous Doppler Sounding System (CDSS) networks. The results are obtained and provided to users in real time. The paper presents the achievements of the project and discusses the challenges faced in the development of the final TechTIDE warning system.

scholarly journals TDMA Datalink Cooperative Navigation Algorithm Based on INS/JTIDS/BA

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 782
Author(s):  
Shuo Cao ◽  
Honglei Qin ◽  
Li Cong ◽  
Yingtao Huang
Keyword(s):  
Distribution System ◽  
Large Scale ◽  
Satellite System ◽  
Time Of Arrival ◽  
Military Operations ◽  
Position Information ◽  
Cooperative Navigation ◽  
Navigation Algorithm ◽  
Geometric Dilution Of Precision ◽  
Global Navigation Satellite

Position information is very important tactical information in large-scale joint military operations. Positioning with datalink time of arrival (TOA) measurements is a primary choice when a global navigation satellite system (GNSS) is not available, datalink members are randomly distributed, only estimates with measurements between navigation sources and positioning users may lead to a unsatisfactory accuracy, and positioning geometry of altitude is poor. A time division multiple address (TDMA) datalink cooperative navigation algorithm based on INS/JTIDS/BA is presented in this paper. The proposed algorithm is used to revise the errors of the inertial navigation system (INS), clock bias is calibrated via round-trip timing (RTT), and altitude is located with height filter. The TDMA datalink cooperative navigation algorithm estimate errors are stated with general navigation measurements, cooperative navigation measurements, and predicted states. Weighted horizontal geometric dilution of precision (WHDOP) of the proposed algorithm and the effect of the cooperative measurements on positioning accuracy is analyzed in theory. We simulate a joint tactical information distribution system (JTIDS) network with multiple members to evaluate the performance of the proposed algorithm. The simulation results show that compared to an extended Kalman filter (EKF) that processes TOA measurements sequentially and a TDMA datalink navigation algorithm without cooperative measurements, the TDMA datalink cooperative navigation algorithm performs better.

scholarly journals A study of atmospheric gravity waves and travelling ionospheric disturbances at equatorial latitudes

1997 ◽  
Vol 15 (8) ◽  
pp. 1048-1056 ◽  
Author(s):  
R. L. Balthazor ◽  
R. J. Moffett
Keyword(s):  
Gravity Waves ◽  
Large Scale ◽  
Ionospheric Disturbance ◽  
Magnetic Equator ◽  
Ionospheric Disturbances ◽  
Atmospheric Gravity Waves ◽  
Opposite Hemisphere ◽  
Travelling Ionospheric Disturbances ◽  
F Region ◽  
Atmospheric Gravity

Abstract. A global coupled thermosphere-ionosphere-plasmasphere model is used to simulate a family of large-scale imperfectly ducted atmospheric gravity waves (AGWs) and associated travelling ionospheric disturbances (TIDs) originating at conjugate magnetic latitudes in the north and south auroral zones and subsequently propagating meridionally to equatorial latitudes. A 'fast' dominant mode and two slower modes are identified. We find that, at the magnetic equator, all the clearly identified modes of AGW interfere constructively and pass through to the opposite hemisphere with unchanged velocity. At F-region altitudes the 'fast' AGW has the largest amplitude, and when northward propagating and southward propagating modes interfere at the equator, the TID (as parameterised by the fractional change in the electron density at the F2 peak) increases in magnitude at the equator. The amplitude of the TID at the magnetic equator is increased compared to mid-latitudes in both upper and lower F-regions with a larger increase in the upper F-region. The ionospheric disturbance at the equator persists in the upper F-region for about 1 hour and in the lower F-region for 2.5 hours after the AGWs first interfere, and it is suggested that this is due to enhancements of the TID by slower AGW modes arriving later at the magnetic equator. The complex effects of the interplays of the TIDs generated in the equatorial plasmasphere are analysed by examining neutral and ion winds predicted by the model, and are demonstrated to be consequences of the forcing of the plasmasphere along the magnetic field lines by the neutral air pressure wave.

The Observation of Large Scale Travelling Ionospheric Disturbances Based on GPS Network

2002 ◽  
Vol 45 (4) ◽  
pp. 469-475 ◽  
Author(s):  
Dong-He ZHANG ◽  
K. Igarashi ◽  
Zuo XIAO ◽  
Guan-Yi MA
Keyword(s):  
Large Scale ◽  
Ionospheric Disturbances ◽  
Travelling Ionospheric Disturbances ◽  
Gps Network

scholarly journals Ionosonde Observations of Spread F and Spread Es at Low and Middle Latitudes during the Recovery Phase of the 7–9 September 2017 Geomagnetic Storm

2021 ◽  
Vol 13 (5) ◽  
pp. 1010
Author(s):  
Lehui Wei ◽  
Chunhua Jiang ◽  
Yaogai Hu ◽  
Ercha Aa ◽  
Wengeng Huang ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Large Scale ◽  
Satellite System ◽  
Recovery Phase ◽  
Ionospheric Irregularities ◽  
Middle Latitudes ◽  
Multiple Observations ◽  
Swarm Satellites ◽  
Spread F ◽  
Global Navigation Satellite

This study presents observations of nighttime spread F/ionospheric irregularities and spread Es at low and middle latitudes in the South East Asia longitude of China sectors during the recovery phase of the 7–9 September 2017 geomagnetic storm. In this study, multiple observations, including a chain of three ionosondes located about the longitude of 100°E, Swarm satellites, and Global Navigation Satellite System (GNSS) ROTI maps, were used to study the development process and evolution characteristics of the nighttime spread F/ionospheric irregularities at low and middle latitudes. Interestingly, spread F and intense spread Es were simultaneously observed by three ionosondes during the recovery phase. Moreover, associated ionospheric irregularities could be observed by Swarm satellites and ground-based GNSS ionospheric TEC. Nighttime spread F and spread Es at low and middle latitudes might be due to multiple off-vertical reflection echoes from the large-scale tilts in the bottom ionosphere. In addition, we found that the periods of the disturbance ionosphere are ~1 h at ZHY station, ~1.5 h at LSH station and ~1 h at PUR station, respectively. It suggested that the large-scale tilts in the bottom ionosphere might be produced by LSTIDs (Large scale Traveling Ionospheric Disturbances), which might be induced by the high-latitude energy inputs during the recovery phase of this storm. Furthermore, the associated ionospheric irregularities observed by satellites and ground-based GNSS receivers might be caused by the local electric field induced by LSTIDs.

scholarly journals A New Method to Improve the Detection of Co-Seismic Ionospheric Disturbances using Sequential Measurement Combination

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2948 ◽  
Author(s):  
Seonho Kang ◽  
Junesol Song ◽  
Deokhwa Han ◽  
Bugyeom Kim ◽  
Hyoungmin So ◽  
...  
Keyword(s):  
Time Derivative ◽  
Tohoku Earthquake ◽  
Satellite System ◽  
Detection Performance ◽  
Ionospheric Delay ◽  
New Method ◽  
Ionospheric Disturbances ◽  
The 2011 Tohoku Earthquake ◽  
Sequential Measurement ◽  
Global Navigation Satellite

Earthquakes generate energy that propagates into the ionosphere and incurs co-seismic ionospheric disturbances (CIDs), which can be observed in ionospheric delay measurements. In most cases, the CID has a weak signal strength, because the energy in the atmosphere transferred from the earthquake dissipates as it travels toward the ionosphere. It is particularly hard to observe at reference stations that are located far from the epicenter. As the number of Global Navigation Satellite System stations and their positions are restricted, it is important to employ weak CID data in the analysis by improving the detection performance of CIDs. In this study, we suggest a new method of detecting CIDs, which mainly uses a sequential measurement combination of the carrier phase-based ionospheric delay data, with a 1-second interval. The proposed method’s performance was compared with conventional methods, including band-pass filters and a representative time-derivative method, using data from the 2011 Tohoku earthquake. As a result, the maximum CID-to-noise ratio can be increased by a maximum of 13% when the proposed method is used, and consequently, the detection performance of the CID can be improved.

scholarly journals POSSÍVEL TID GERADO NA REGIÃO POLAR E OBSERVADO SOBRE ESTAÇÕES EQUATORIAIS E DE BAIXAS LATITUDES

2018 ◽  
Vol 4 ◽  
pp. 46-61
Author(s):  
Elio Pessoa Cazuza ◽  
Anderson Luiz Pinheiro De Oliveira ◽  
Hadassa Raquel Peixoto Jácome ◽  
Gilvan Luiz Borba ◽  
José Pedro Silva Junior ◽  
...  
Keyword(s):  
Large Scale ◽  
Ionospheric Disturbances ◽  
Radio Observatory ◽  
Travelling Ionospheric Disturbances

Os Distúrbios Ionosféricos Propagantes (TID’s - Travelling Ionospheric Disturbances) são irregularidades no plasma ionosférico que se propagam com velocidades da ordem de dezenas a poucas centenas de quilômetros por hora. Nesse trabalho, foram detectadas e caracterizadas perturbações do tipo LSTID’s (Large scale Travelling Ionospheric Disturbances), em baixas latitudes, durante intensas tempestades geomagnéticas e também a forma como se propagação. Utilizou-se registros ionosféricos obtidos a partir de digissondas do tipo CADI (Canadian Advanced Digital Ionosonde) localizada na cidade de Natal e do tipo DSP (Digisonde Portable Souder) localizadas nas cidades de Cachoeira Paulista, Ramey e Eglin. Os dados de sondagem de Ramey e Eglin foram disponibilizados pela Global Ionosphere Radio Observatory (GIRO). Para observar os efeitos de tempestades sobre a ionosfera polar, foram utilizadas imagens aurorais do polo Norte, obtidas pelo satélite POLAR, que mostraram a intensificação do eletrojato auroral pela injeção de partículas nas cúspides. O período analisado compreendeu os dias 06 e 07 de abril de 2000 e os índices utilizados para caracterizar a atividade magnética nesse período foram Dst, Kp, e AE, além da componente Bz do campo magnético interplanetário. A tempestade ocorrida no dia 6 de abril apresentou um Dstmin = - 288 nT. A partir de gráficos de isolinhas foram verificados comportamentos anômalos da ionosfera sobre as quatro cidades, caracterizando a propagação como sendo do tipo LSTID’s, gerados pela expansão do oval auroral nos polos.

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