Study of Ionospheric Variability Using GNSS Observations

Taoufiq, Jouan; Bouziani, Mourad; Rachid, Azzouzi; Amory‐Mazaudier, Christine

doi:10.4236/pos.2018.94006

Cited by 3 publications

(3 citation statements)

References 6 publications

(5 reference statements)

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“…Several studies have already been conducted on TEC variations during disturbed geomagnetic activities. It has been found in general that TEC variations follow solar activity trend [17]- [22]. In other words, TEC variations increase with solar activity intensity.…”

Section: Introductionmentioning

confidence: 93%

TEC Variability during Fluctuating Events at Koudougou Station during Solar Cycle 24

Pahima¹,

Gnabahou²,

Sandwidi³

et al. 2022

IJG

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This paper deals with TEC variability during fluctuating geomagnetic events (FE) during solar cycle 24 at Koudougou station (lat: 12˚15'N; Geo long: −2˚20'E). The study was done by comparing TEC variations during FE days with those of quiet days (QA). Comparison was made taking into account solar phases' and seasons' influences. FE's and QA's TEC curves are characterized by dome profiles. All graphs show two troughs, one in the morning (0500 LT) and the second in the evening (around 2000 LT) and a peak around 1400 LT during all solar phases and winter months and around 1500 LT for the remaining seasons. Both troughs are caused by the decrease of the photo ionization and an increase of the recombination phenomena, as well for FE as for QA periods. FE cause positive storms during all solar phases as well as during seasons and some negative storms during spring and summer months and minimum and maximum solar phases.

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Section: Introductionmentioning

confidence: 93%

TEC Variability during Fluctuating Events at Koudougou Station during Solar Cycle 24

Pahima¹,

Gnabahou²,

Sandwidi³

et al. 2022

IJG

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“…Carrier phase signal and code signal go through phase path and group path, respectively, in the ionospheric region and the corresponding delay is called phase lead and code delay. The phase refraction index is used respectively, n p 、group refraction index n g combined with the mathematical equation, the TEC (Total Electron Content) indicates the total amount of electrons contained in the column per unit area of ionosphere, and it is generally representative 10 16 ~10 17 electronic per square (Yuan, 2002;Camps et al, 2017;Taoufiq et al, 2018;Liu, 2020).…”

Section: Ionospheric Delay Correctionmentioning

confidence: 99%

Correction of Atmospheric Delay Error of Airborne and Spaceborne GNSS-R Sea Surface Altimetry

Yan

Zheng

et al. 2022

Front. Earth Sci.

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Improving the measurement accuracy is a necessary condition for sea surface altimetry using the Global Navigation Satellite System Reflectometry (GNSS-R). The ionosphere and troposphere delay the transmission of satellite signals, which directly affect the measuring accuracy. The influence of the atmospheric environment on GNSS-R altimetry differs from different platforms. By analyzing and sorting out the altimetry data of airborne and spaceborne platforms, this paper studies the variation law of signal delay in the altimetry process from the point of view of mathematical geometry, which provides an example for improving the precision of GNSS-R altimetry measurements. Firstly, in order to facilitate data analysis, this paper constructed an altimetry model with the GNSS satellite position, specular reflection point position, receiver position as nodes, classified direct signals, and reflected signals. Secondly, calculate ionospheric puncture point coordinates , and interpolate GIM products provided by IGS using time and puncture point coordinates to obtain the VTEC value in the vertical direction of the puncture point, which was converted into the path direction STEC by projection function, the ionospheric delay of each part was obtained in this way. The tropospheric delay of each part is considered for the along-path component and the geometric component, the delay of along-path component was calculated by the UNB3m model, and the delay of geometric component was calculated by the equation provided by Nikolaidou (Nikolaidou et al., 2021). Thirdly, by comparing the sea surface height inversion results with or without atmospheric delay correction with the mean sea surface height provided by DTU15, the measurement accuracy with atmospheric delay correction is obviously improved. The study results of the influence of atmospheric delay on the altimetry experiments precision error of airborne and spaceborne platforms show that the error magnitude is consistent with the existing literature. In the airborne experiment, the influence of the ionosphere is negligible and the troposphere has sub-meter influence on altimetry results, among which the tropospheric along-path delay component occupies a high proportion. The geometric delay component has a high correlation with the satellite elevation angle and its influence on the measurement accuracy decreases with the elevation angle increase. The effect of this factor can be effectively weakened by setting a high satellite cutoff angle. In the spaceborne experiment, the effect of atmospheric delay on altimetry results fluctuates in the range of 3∼5 m when the satellite elevation angle is greater than 60°. In this paper, the method of calculating signal atmospheric delay through geometric relation to improving the measurement accuracy can provide an example for the atmospheric delay correction of GNSS-R ocean altimetry with high precision and spatial resolution in future research.

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“…As the system matures, its application field is also wider (Taoufiq et al, 2018;Titouni et al, 2017;Andrianarison et al, 2017). GNSS meteorology is the latest application of GNSS technology in the detection of atmospheric atmosphere by using GNSS theory and technology to remotely measure the Earth's atmosphere to determine atmospheric temperature and water vapor content, and to monitor climate change.…”

Section: Introductionmentioning

confidence: 99%

GNSS/MET Station Equipment Maintenance and Product Application

Ma¹,

Sun²,

Zhang³

et al. 2019

GEP

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Based on the use of Global Navigation Satellite System (GNSS) for meteorological detection in the world, we used the GNSS/MET detection equipment in the meteorological departments of Liaoning Province of China and its data to study and summarize the maintenance methods of GNSS/MET (Global Navigation Satellite System Meteorology) detection equipment and the application of water vapor products in operational systems. The results show that: 1) For GNSS/MET failures, specific inspections and classifications can be performed according to different phenomena; 2) The GNSS water vapor measurement station samples every 30 seconds, forming one set of GNSS data every hour, and can detonate the atmospheric precipitation by solving the original data; 3) Using the "Navigation Satellite Remote Sensing Water Vapor Application Management System", the GNSS/MET water vapor products can be directly displayed. We can get the conclusion that GNSS/MET has far-reaching significance for studying the law of atmospheric water vapor changes and enhancing the ability to monitor severe weather such as heavy rain and strong convection.

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Study of Ionospheric Variability Using GNSS Observations

Cited by 3 publications

References 6 publications

TEC Variability during Fluctuating Events at Koudougou Station during Solar Cycle 24

TEC Variability during Fluctuating Events at Koudougou Station during Solar Cycle 24

Correction of Atmospheric Delay Error of Airborne and Spaceborne GNSS-R Sea Surface Altimetry

GNSS/MET Station Equipment Maintenance and Product Application

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