Global Positioning System

Hofmann-Wellenhof, Bernhard; Lichtenegger, Herbert; Collins, James J.

doi:10.1007/978-3-7091-5126-6

Cited by 331 publications

(245 citation statements)

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“…Phase measurements in the GPS can be made with a high degree of accuracy corresponding to the error of TEC determination of at least 10 14 m −2 when averaged on a 30-s time interval, with some uncertainty of the initial value of TEC, however (Hofmann-Wellenhof et al, 1992). This makes it possible to detect ionization irregularities and wave processes in the ionosphere over a wide range of amplitudes (up to 10 −4 of the diurnal TEC variation) and periods (from 24 h to 5 min).…”

Section: Methods Of Processing the Data From The Global Network: Selecmentioning

confidence: 99%

Isolated ionospheric disturbances as deduced from global GPS network

2004

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Abstract.We investigate an unusual class of medium-scale traveling ionospheric disturbances of the nonwave type, isolated ionospheric disturbances (IIDs) that manifest themselves in total electron content (TEC) variations in the form of single aperiodic negative TEC disturbances of a duration of about 10 min (the total electron content spikes, TECS). The data were obtained using the technology of global detection of ionospheric disturbances using measurements of TEC variations from a global network of receivers of the GPS. For the first time, we present the TECS morphology for 170 days in 1998-2001. The total number of TEC series, with a duration of each series of about 2.3 h (2h 18m), exceeded 850 000. It was found that TECS are observed in no more than 1-2% of the total number of TEC series mainly in the nighttime in the spring and autumn periods. The TECS amplitude exceeds the mean value of the "background" TEC variation amplitude by a factor of 5-10 as a minimum. TECS represent a local phenomenon with a typical radius of spatial correlation not larger than 500 km. The IID-induced TEC variations are similar in their amplitude, form and duration to the TEC response to shock-acoustic waves (SAW) generated during rocket launchings and earthquakes. However, the IID propagation velocity is less than the SAW velocity (800-1000 m/s) and are most likely to correspond to the velocity of background medium-scale acoustic-gravity waves, on the order of 100-200 m/s.

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Section: Methods Of Processing the Data From The Global Network: Selecmentioning

confidence: 99%

Isolated ionospheric disturbances as deduced from global GPS network

2004

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“…This time delay being a function of electron density when measured by using dual frequency receiver can compute the TEC. So, the GPS receiver is one of the most practicable tools for TEC study [3] [4]. The ionospheric delay constitutes the major source of error for a single frequency GNSS operation.…”

Section: Introductionmentioning

confidence: 99%

GPS-TEC Variation during Low to High Solar Activity Period (2010-2014) under the Northern Crest of Indian Equatorial Ionization Anomaly Region

Patel¹,

Karia²,

Pathak³

2017

POS

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The measurements of ionospheric TEC (total electron content) are conducted at a low latitude Indian station Surat (21.16˚N, 72.78˚E Geog.), which lies under the northern crest of the equatorial anomaly in Indian region. The data obtained are for a period of five years from low to high solar activity (2010-2014) using GPS (Global Positioning System) receiver. In this study, we report the diurnal and seasonal variation of GPS-TEC, dependence of GPS-TEC with solar activity, geomagnetic condition and EEJ strength. From the seasonal analysis, it is found that greater values of the GPS-TEC are observed during equinox season followed by winter and summer. The appearance (in the year 2011 and 2014) and disappearance (in the year 2010 and 2012) of "winter anomaly" have been observed at the station. From the correlation of GPS-TEC with different solar indices, i.e. solar EUV flux, F10.7 cm solar radio flux and Zurich sunspot number (SSN), it is concluded that the solar index EUV flux is a better controller of GPS-TEC, compared to F10.7 cm and SSN. Further, it is observed that there is no effect of rising solar activity on correlation. Moreover, the percentage variability of GPS-TEC and the standard deviation of GPS-TEC obtained for quiet and disturbed days show that dependence of GPS-TEC on geomagnetic condition is seasonal. Also, there is a positive correlation observed between GPS-TEC and EEJ strength.

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“…The ionosphere is the major source of errors in the GNSS positioning (Hofmann-Wellenhof et al, 1992). In this region, ionizing radiation from the Sun causes the existence of electrons, in the quantities that influence radio-waves propagation (Kleusberg and Teunissen, 1996).…”

Section: Introductionmentioning

confidence: 99%

Modelling extreme values of the total electron content: Case study of Serbia

et al. 2017

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This paper is dedicated to modeling extreme TEC (Total Electron Content) values at the territory of Serbia. For the extreme TEC values, we consider the maximum values from the peak of the 11-year cycle of solar activity in the years 2013, 2014 and 2015 for the days of the winter and summer solstice and autumnal and vernal equinox. The average TEC values between 10 and 12 UT (Universal Time) were treated. As the basic data for all processing, we used GNSS (Global Navigation Satellite System) observation obtained by three permanent stations located in the territory of Serbia. Those data, we accept as actual, i.e. as a "true TEC values". The main objectives of this research were to examine the possibility to use two machine learning techniques: neural networks and support vector machine. In order to emphasize the quality of applied techniques, all results are adequately compared to the TEC values obtained by using International Reference Ionosphere global model. In addition, we separately analyzed the quality of techniques throughout temporal and spatial-temporal approach.

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Global Positioning System

Cited by 331 publications

References 0 publications

Isolated ionospheric disturbances as deduced from global GPS network

Isolated ionospheric disturbances as deduced from global GPS network

GPS-TEC Variation during Low to High Solar Activity Period (2010-2014) under the Northern Crest of Indian Equatorial Ionization Anomaly Region

Modelling extreme values of the total electron content: Case study of Serbia

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