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Ionospheric scintillation and TEC studies over Brazil using GNSS: progresses and problems

Ionospheric scintillation and TEC studies over Brazil using GNSS: progresses and problems. E. R. de Paula 1 , M. T.H.A. Muella 2 , J.F.G. Monico 3 , P. M. de Siqueira 1 , A.O. Moraes 4 , R.Y.C. Cueva 1 ,L. F. C. de Rezende 1 , A.C. Neto 1 , A. P. S. Dutra 1 and P. C. P. dos Santos 1

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Ionospheric scintillation and TEC studies over Brazil using GNSS: progresses and problems

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  1. Ionospheric scintillation and TEC studies over Brazil using GNSS: progresses and problems E. R. de Paula1, M. T.H.A. Muella2, J.F.G. Monico3, P. M. de Siqueira1, A.O. Moraes4, R.Y.C. Cueva1,L. F. C. de Rezende1, A.C. Neto1, A. P. S. Dutra1and P. C. P. dos Santos1 1- INPE AeronomyDivision S. J. dos Campos São Paulo Brazileurico@dae.inpe.br 2- UNIVAP São José dos Campos São Paulo, Brazil 3-UNESP Presidente Prudente São Paulo Brazil 4- IAE Instituto de Aeronáutica e Espaço S.J. dos Campos São Paulo Brazil

  2. OUTLINE • GNSS networks atBrazil: SCINTMON(EURICO), LISN(EURICO/CESAR), CIGALA (Galera), RBMC/IBGE(Sonia Costa), SIPEG (ÍcaroVitorello) and IGS • S4 and TEC scientificstudies • Scintillationeffects over GNSS • Network operationalproblems • S4 calculationsfromdifferent systems – each system has it ownmethodologytocalculate S4 -> problem • Differentmodels for absolute TEC calculation • Preliminar resultsfrom a campaigntostudythebehaviorofdifferent GNSS receiversduringscintillation • Initiatives for scintillationprediction

  3. GPS receivers: (SCINTEC-CASCADE) INPE Receivers single L1 frequency Belem-PA Belo Horizonte-MG Boa Vista-RR Brasilia-DF Cachoeira Paulista-SP Cuiabá-MT Manaus-AM Natal-RN Pato Branco-PR Presidente Prudente-SP Santa Maria-RS São João do Cariri-PB São José dos Campos-SP São Luís-MA Tefé-AM MAGNETIC EQUATOR • Sample Rate: 50Hz • GEC-PLESSEY Card • INPE/CORNELL • Zonal Velocity capability • Amplitude Scintillation (S4)

  4. GPS stations in BRAZIL: (BLISN) CURRENT STATIONS - LISN LISN / NSF Alta Floresta-MT Belo Horizonte-MG Boa Vista-RR Brasília-DF Cachoeira Paulista-SP Cuiabá-MT Dourados-MS Ilhéus-BA Imperatriz-MA Natal-RN Parintins-AM Pato Branco - PR Petrolina-PE Porto Velho-RO Rio Branco-AC Santa Maria-RS São Luís-MA São José dos Campos-SP São Gabriel da Cachoeira-AM Santarém-PA Tefé-AM MAGNETIC EQUATOR • Sample rate: 50 Hz • INPE/BC(NSF) • TEC and S4 • Novatel 4004 B (19) e Ashtech (2)

  5. RBMC/IBGE GNSS NETWORK • Dual Frequency receivers -> TEC • Contact Sonia Costa: sonia.alves@ibge.gov.br

  6. GNSS POSITIONING INTEGRATED SYSTEM FOR GEODYNAMIC STUDIES– SIPEG (Dr. Ícaro Vitorello) Stations in Operation and Predicted for 2012 Blue 09- Permanent Yellow 22- Temporarily Red 19- Predicted for 2012 Light blue 08-Permanent IBGE; 04 with tide gauges 03 with PTH sensor Dual Frequency 105 Trimble NET R8 -> TEC Contact Ícaro Vitorello: icaro@dge.inpe.br

  7. S4 AND TEC SCIENTIFIC STUDIES • Irregularity zonal velocityusingcross-correlationmethologywithspaced GNSS receivers (Márcio Muella) • Irregularity (S4) and TEC morphologydueto solar flux, local time, season, location • TEC behaviorduringmagneticstorms • InfluenceofMSTIDsandGWsontheirregularitygeneration • SSW (SuddenStratosphericWarming) effects over scintillationand TEC • TEC periodicities • Scintillationmodels (WAM, E. Costa/PUC, GIM( Yannick)) validation

  8. IRREGULARITY (S4) AND TEC MORPHOLOGY DUE TO SOLAR FLUX, LOCAL TIME, SEASON, LOCATION

  9. MAGNETIC STORMS: INHIBITED OR TRIGGER IONOSPHERIC SCINTILLATION Example of a case of storm triggered scintillation. Example of a case of storm inhibited scintillation.

  10. LOSS OF LOCK DUE TO SCINTILLATION Another lock loss Long period

  11. DGPS LossofSignal in onepetroleumdrillingship • Boa tarde,Gostaria de saber se é possívelvocê me enviaralgum dado referente a cintilação entre a noite do dia 19/09/2012 e a madrugada do dia 20/09/2012?Verificamosquetivemosumaperda de sinal de nossossistemas DGPS e gostariamosdessainformação.Desdejáagradeço o retordoOficial de Náutica - JansenBridgeSkandi SalvadorTel.:   55 + 22 2105-8358 Mob.: 55 + 21 7123-8252 Sat :+55 21 870 764 885927 www.norskan.com.br

  12. DGPS Loss of Signal in one petroleum drilling ship-S4 from CIGALA Septentrio receiver on 09/19-20/2012

  13. GENERAL PROBLEMS RELATED WITH GNSS NETWORKS/DATA ANALYSIS ETC • Lackofworkingpeopleatthestation • Lackof training for thesepeople • Lackofdailyremotestationmonitoring • Lackof financial support for remorestationmaintenance: travels, local people, damagedequipmentreposition • Lackof financial supporttopurchase more receivers • Old micros, receivers, antennasetc • Lackofsupporttopeopleatremotestations • In manystations, mainlyatAmazonregion, there are frequentelectricalpowerfailures • Low rate/failing Internet connections sharedwithmany links • Lightningsproblemsandlackofprotectiondevices • Multipathproblems (normalygrowingtreesaroundtheantennas) • Firmware problems (LISN for instancealmost 18 stationsneedstobeupdated) • Clocksteeringproblem (LISN) • Non accessto some codes • Lossof data in therecording medias/servers • . • . • CONSEQUENCE OF THESE PROBLEMS (FOR INSTANCE): • LISN: only 03 out of 21 are operationalatthemomentatBrazil • SCINTEC/CASCADE: only 06 out of 20 are operationalatthemoment

  14. Models for absolute TEC calculation in use at INPE Nagoya-TECMAP (suitable for dense networks) UNB NOAA (US-TEC) MODION (UNESP) GI - Model

  15. DIFFERENT GPS RECEIVERS CAMPAIGN TO CHECK PERFORMANCE DURING SCINTILLATION (SEPTENTRIO, NOVATEL 4004B AND GPS STATION 6, ASTRA AND GEC-PLESSEY)

  16. DIFFERENT GPS RECEIVERS CAMPAIGN TO CHECK PERFORMANCE DURING SCINTILLATION (STANFORD SYSTEM – JUST ARRIVED)

  17. Prediction of ionospheric scintillation (L.F. C. de Rezende, 2009, Master Dissertation ) - Ionospheric scintillation prediction is also been developed at INPE using vertical plasma drift from digisonde data

  18. Thanks for the attention • References relative to this work: eurico@dae.inpe.br

  19. DGPS Loss of Signal in one petroleum drilling ship-S4 from CIGALA Septentrio receiver on 09/19/2012

  20. IONOSPHERIC SCINTILLATION EFFECTS OVER GPS SIGNAL Dilution of precision (DOP) The expression “dilution of precision” (DOP) is used to name the effect of satellite geometry on the precision of navigation solution. Good geometry Bad geometry

  21. Measured decorrelation times fast scintillation (small 0) are associated with high S4 (Carrano and Groves, 2010) shows a histogram describing the overall distribution of the measured decorrelation times. The histogram was computed for the S4 intervals described above, and for 0 intervals that were 0.1 seconds wide. An important feature of Figure 7 is that most of the fast scintillation cases (small 0) are associated with strong amplitude scintillation, i.e., high S4. When S4 is greater than 0.7, the decorrelation time is generally less than 0.3 seconds.

  22. GENERAL PROBLEMS RELATED WITH GNSS NETWORKS/DATA ANALYSIS ETC • PROBLEMAS LOCAIS • Na região amazônica: • Energia elétrica de baixa qualidade com muitas oscilações. Nobreak e baterias são de extremas necessidades; • Internet via radio de baixa velocidade (menos de 500 Kbps) compartilhada com todo o campus; • Falta de dispositivo para proteção contra descargas atmosféricas, pois esta região tem registrado vários problemas com a falta destes dispositivos; • A presença de arvores introduz ruídos nos sinais monitorados. • Falta de pessoal com habilidades técnicas especificas. • Nos demais locais, o principal problema é a falta de pessoas com habilidades técnicas especificas para atender a nossa demanda, e pratica de solicitação de favores não tem ajudado muito. • Em algumas estações Lisn/Cascade precisamos trocar o computador e atualizar urgentemente o Firmware e scripts das estações remotas, mas não temos recursos para isto. • Para as estações cascade, o principal problema está no software de monitoração, que por ter um código fechado nos limita. O equipamento já está obsoleto.

  23. Cumulative Distribution Function of amplitude for 6 Dec 2001

  24. Ionospheric scintillation and TEC studies over Brazil using GNSS: progresses and problems • Ionospheric scintillation and TEC studies over Brazil using GNSS: progresses and problems • E. R. de Paula1, M. T.H.A. Muella2, J.F.G. Monico3, P. M. de Siqueira1, A.O. Moraes4, R.Y.C. Cueva1,L. F. C. de Rezende1, A.C. Neto1, A. P. S. Dutra1 and P. C. P. dos Santos1 • 1- INPE Aeronomy Division S. J. dos Campos São Paulo Brazil eurico@dae.inpe.br • 2- UNIVAP São José dos Campos São Paulo, Brazil • 3-UNESP Presidente Prudente São Paulo Brazil • 4- IAE Instituto de Aeronáutica e Espaço S.J. dos Campos São Paulo Brazil • In this talk we present first the SCINTEC (INPE/Cornell GPS receiver network) amplitude scintillation, the BLISN (Brazilian Low-Latitude Ionospheric Sensor Network that provides amplitude and phase scintillation and TEC) and the BCIGALA (Brazilian CIGALA) characteristics. Following we will present the progresses including scientific studies and applications using the S4 and TEC data measured at those GNSS receiver networks over Brazil, a region with a large magnetic declination and with a large occurrence of ionospheric irregularities. Some cases of ionospheric irregularity effects over GNSS positioning are going to be reported. We also will report problems with GNSS network maintenance mainly at remote sites including their transmission using external networks, with data manipulation (availability management, filtering and storaging), with scintillation indices from different receivers, with different models such as UNB(Canada), STELAB-INPE(Nagoya), USTEC (NOAA), MODION (UNESP), GI (UTFPR) to estimate absolute TEC, S4 and TEC in almost real time mapping (nowcasting) and some trials to forecast scintillation. Finally some preliminar results from a campaign at INPE to study the behavior of different GNSS receivers under scintillation environment will be presented.

  25. The variability of amplitude scintillation patterns (Alison´s Phd) S4=0.9 Figure 4 shows four examples illustrating the variability in the decorrelation time computed from GPS L1 amplitude measurements made with very distinct 0 values: 0.94, 0.68, 0.43 and 0.18 seconds. This figure serves to exemplify the variability of amplitude scintillation patterns. The 0 value is defined as the time lag at which the autocorrelation function falls off by e-1 from its maximum (zero lag) value

  26. SCINTILLATION AMPLITUDE DISTRIBUTIONS (ALISON’s Phd)

  27. InfluenceofMSTIDsandGWsontheirregularitygeneration (Ricardo´s PhD)

  28. Efeito do Ciclo Solar

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