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  • Articles  (4)
  • Open Access-Papers  (4)
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  • Articles  (4)
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  • 1
    Publication Date: 2020-11-19
    Description: We study ionospheric scintillation on GNSS signals at equatorial latitudes to draw a climatological picture of the low latitude ionosphere in the Brazilian sector during the ascending phase of the upcoming 2013 solar maximum. Such data have been acquired during the early stage of the CIGALA project (http://cigala. galileoic.org/), funded by the European Commission under the 7th Framework Program and the outcome of this work is part of the scientific achievements of the project itself. The considered network is based on the novel PolaRxS receivers, developed and deployed specifically to comply with the aims of the FP7 project. The PolaRxS is able to monitor ionospheric scintillation for all operational and upcoming GNSS constellations (GPS, GLONASS, Compass, GALILEO) and corresponding frequencies in the L-band. The ionosphere over the Brazilian territory, being close to the southern crest of the Equatorial Ionospheric Anomaly (EIA), is heavily affected by intense scintillation conditions. The sector under investigation is also very peculiar with respect to other low latitude regions, because of its proximity to the South Atlantic Magnetic Anomaly (SAMA). The application of the Ground Based Scintillation Climatology (GBSC) technique, for the first time simultaneously on GPS and GLONASS data and on both L1 and L2 frequencies, highlights the joint effect of the EIA and of the SAMA in producing the irregularities leading to scintillation.
    Description: Published
    Description: 199-206
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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  • 2
    Publication Date: 2020-12-14
    Description: This work presents a contribution to the understanding of the ionospheric triggering of L-band scintillation in the region over São Paulo state in Brazil, under high solar activity. In particular, a climatological analysis of Global Navigation Satellite Systems (GNSS) data acquired in 2012 is presented to highlight the relationship between intensity and variability of the total electron content (TEC) gradients and the occurrence of ionospheric scintillation. The analysis is based on the GNSS data acquired by a dense distribution of receivers and exploits the integration of a dedicated TEC calibration technique into the Ground Based Scintillation Climatology (GBSC), previously developed at the Istituto Nazionale di Geofisica e Vulcanologia. Such integration enables representing the local ionospheric features through climatological maps of calibrated TEC and TEC gradients and of amplitude scintillation occurrence. The disentanglement of the contribution to the TEC variations due to zonal and meridional gradients conveys insight into the relation between the scintillation occurrence and the morphology of the TEC variability. The importance of the information provided by the TEC gradients variability and the role of the meridional TEC gradients in driving scintillation are critically described.
    Description: Published
    Description: A36
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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  • 3
    Publication Date: 2019-02-01
    Description: The aim of this study is to investigate the performance of a method based on improving the stochastic model to mitigate ionospheric scintillation effects on GNSS positioning by processing experimental data from GISTM (GPS Ionospheric Scintillation and TEC Monitor) receivers, which are capable of computing amplitude and phase scintillation parameters from GPS signals. We applied the approach to mitigate ionospheric scintillation effects on GNSS positioning, in conjunction with the estimation of an ionospheric parameter, considered as a stochastic process. This approach produced, in a single epoch point positioning solution, an improvement on height and 3D accuracy of the order of 31% and of 45%, respectively, when applied in a northern high latitude GISTM network under a moderate scintillation scenario. In this project we investigated the case study of 21 November 2009 using data from GISTM stations located in Antarctica and applying the same scintillation mitigation approach to a Precise Point Positioning (PPP) solution. We used an in-house software under development at Unesp. Despite the solar activity being very low, observations from ACE indicated the influence of a recurrent coronal hole high speed stream. Solar wind speed ranged from 430 to 575 km/s, with Bz fluctuations from -8 to +9 nT, generally leading to the formation of ionospheric irregularities responsible of scintillation effects on GNSS signals. Preliminary results from this case study in the PPP mode are encouraging, showing improvements of the order of 26% in 3D accuracy when applying the proposed scintillation stochastic modeling.
    Description: Unpublished
    Description: Buenos Aires - Argentina
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: open
    Keywords: GNSS Scintillation ; mitigation techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
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  • 4
    Publication Date: 2021-11-26
    Description: We estimate the zonal drift velocity of small-scale ionospheric irregularities at low latitude by leveraging the spaced-receivers technique applied to two GNSS receivers for scintillation monitoring installed along the magnetic parallel passing in Presidente Prudente (Brazil, magnetic latitude 12.8°S). The investigated ionospheric sector is ideal to study small-scale irregularities, being located close to the expected position of the southern crest of the equatorial ionospheric anomaly. The measurement campaign took place between September 2013 and February 2014, i.e. equinox and summer solstice seasons under solar maximum, during which the probability of formation of small-scale irregularities is expected to maximize. We found that the hourly average of the velocity increases up to 135 m/s right after the local sunset at ionospheric altitudes and then smoothly decreases in the next hours. Such measurements are in agreement with independent estimations of the velocity made by the Incoherent Scatter Radar located at the Jicamarca Radio Observatory (magnetic latitude 0.1°N), by the Boa Vista Ionosonde (magnetic latitude 12.0°N), and by applying a recently-developed empirical regional short-term forecasting model. Additionally, we investigated the relationship with the percentage occurrence of amplitude scintillation; we report that it is exponentially dependent on the zonal velocity of the irregularities that cause it.
    Description: Published
    Description: 450–461
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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