Statistical evaluation of GLONASS amplitude scintillation over low latitudes in the Brazilian territory

Moraes, Alison de Oliveira; Muella, M. T. A. H.; Paula, E. R. de; Oliveira, César Buchile Abud de; Terra, William P.; Perrella, Waldecir João; Meibach-Rosa, P. R. P.

doi:10.1016/j.asr.2017.09.032

Cited by 29 publications

(14 citation statements)

References 43 publications

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“…Previously, GLONASS satellites were not included in the drift velocity estimation study due to the signals' notably higher phase noise as compared to the other GNSS systems (Wang & Morton, ). Similar issues have been observed in other ionospheric scintillation studies (de Oliveira Moraes et al, ; Sreeja et al, ).…”

Section: Methodssupporting

confidence: 87%

New Results on Ionospheric Irregularity Drift Velocity Estimation Using Multi‐GNSS Spaced‐Receiver Array During High‐Latitude Phase Scintillation

2018

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The spaced‐receiver technique using Global Navigation Satellite Systems (GNSS) receivers offers an inexpensive approach for estimating ionospheric irregularity velocity during ionospheric scintillations. Our previous work has demonstrated that correlative studies of the GNSS carrier phase variations can be used to derive irregularity drift velocity at high latitudes. This study expanded upon our previous projects by incorporating Global Navigation Satellite System (GLONASS) signals, investigation on ionospheric irregularity height assumption, and all‐sky imager measurements into the methodology. A case study is presented based on Global Positioning System, Galileo, and GLONASS measurements during a geomagnetic storm event on 20 December 2015, obtained from a closely spaced receiver array at Poker Flat Research Range near Fairbanks, Alaska. The GNSS‐estimated irregularity drift velocities are in general agreement with the measurements from the Poker Flat Incoherent Scatter Radar and the Poker Flat all‐sky imager. The study also shows that the irregularity altitude assumption will not lead to significant variations in the irregularity drift velocity estimates, especially for satellites with relatively high elevations. The techniques presented in this paper demonstrate that GNSS receiver arrays can be used as powerful means to monitor the ionospheric plasma dynamics during space weather events.

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Section: Methodssupporting

confidence: 87%

New Results on Ionospheric Irregularity Drift Velocity Estimation Using Multi‐GNSS Spaced‐Receiver Array During High‐Latitude Phase Scintillation

2018

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“…A pattern may be noticed (red solid line) and it starts increasing from September, reaching its maximum in November, presenting a gradual decrease during December to March. The presence of EPB structures or scintillation is very rare over the Brazilian region during April-August, and then this scintillation activity through the months is in agreement with Sobral et al (2002) and Moraes et al (2017b). Figure 7c shows a comparison between the averaged empirical probability distribution and the average trend of the V pk values.…”

Section: Resultsmentioning

confidence: 69%

Climatology of the scintillation onset over southern Brazil

et al. 2018

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Abstract. This work presents an analysis of the climatology of the onset time of ionospheric scintillations at low latitude over the southern Brazilian territory near the peak of the equatorial ionization anomaly (EIA). Data from L1 frequency GPS receiver located in Cachoeira Paulista (22.4 • S, 45.0 • W; dip latitude 16.9 • S), from September 1998 to November 2014, covering a period between solar cycles 23 and 24, were used in the present analysis of the scintillation onset time. The results show that the start time of the ionospheric scintillation follows a pattern, starting about 40 min earlier, in the months of November and December, when compared to January and February. The analyses presented here show that such temporal behavior seems to be associated with the ionospheric prereversal vertical drift (PRVD) magnitude and time. The influence of solar activity in the percentage of GPS links affected is also addressed together with the respective ionospheric prereversal vertical drift behavior. Based on this climatological study a set of empirical equations is proposed to be used for a GNSS alert about the scintillation prediction. The identification of this kind of pattern may support GNSS applications for aviation and oil extraction maritime stations positioning.

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“…More recently, Jiao et al (2016) showed that fading events are specially pronounced on L2C (1227.60 MHz) and L5 (1176.45 MHz) signals and that the amount of fades deeper than 15 dB may reach 10 times the number of similar events on L1 (1575.42 MHz) signals, depending on location. In Moraes, Muella, et al (2017), a statistical analysis compares the occurrence of scintillation in the Global Navigation Satellite System L1 and L2 frequency bands. The results show that during the summer and spring seasons, the probability of intense scintillation events in the southern crest of the anomaly (dip À12°to À20°) is approximately twice that observed around the geomagnetic equator.…”

Section: Introductionmentioning

confidence: 99%

Ionospheric Scintillation Fading Coefficients for the GPS L1, L2, and L5 Frequencies

et al. 2018

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The terrestrial ionosphere over low‐latitude regions presents the unique phenomena of the equatorial ionization anomaly (characterized by global maximum in plasma concentration) and plasma‐depleted regions known as equatorial plasma bubbles and associated smaller‐scale plasma irregularities. Transionospheric radio signals such as those from Global Navigation Satellite Systems constellations, traveling across this ambient, may suffer severe scintillation in amplitude and phase due to these plasma structures. Presently, three civilian signals available for GPS users, at L1 (1575.42 MHz), L2C (1227.60 MHz), and L5 (1176.45 MHz) are used to investigate the propagation effects due to these irregularities. The purpose of the present work is to evaluate statistically the distribution of severe fade events for each of these carrier frequencies based on the nonlinear ionospheric propagation effects as represented by the fading coefficients of α‐μ distribution. The results from the analyses of data sets recorded by stations at different geomagnetic latitude locations in Brazil show that regions closer to the equatorial ionization anomaly crest present higher probability of severe fade events. Additionally, the L5 signals, dedicated for safety‐of‐life applications, revealed more unfavorable results when compared to the L1 and L2C frequencies. The results further showed that for 0.8 ≤ S4 ≤ 1.0 the probabilities of fades deeper than −10 dB were between 8.0% and 6.5% depending on the station position. Considering the case of fades deeper than −20 dB, the results reach values near 1%, which is quite concerning. These results show empirically the fading environment that users of the new civilian signals may experience in low‐latitude region. Additionally, the fading coefficients may help in the comprehension of the distribution of amplitude scintillation and its relation with the frequency used, aiding in the future the development of signal processing algorithms capable to mitigate errors for navigation users.

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Statistical evaluation of GLONASS amplitude scintillation over low latitudes in the Brazilian territory

Cited by 29 publications

References 43 publications

New Results on Ionospheric Irregularity Drift Velocity Estimation Using Multi‐GNSS Spaced‐Receiver Array During High‐Latitude Phase Scintillation

New Results on Ionospheric Irregularity Drift Velocity Estimation Using Multi‐GNSS Spaced‐Receiver Array During High‐Latitude Phase Scintillation

Climatology of the scintillation onset over southern Brazil

Ionospheric Scintillation Fading Coefficients for the GPS L1, L2, and L5 Frequencies

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