The influence of the protonosphere on GPS observations: Model simulations

Lunt, N.; Kersley, L.; Bailey, G. J.

doi:10.1029/1999rs900002

Cited by 79 publications

(70 citation statements)

References 14 publications

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“…This upper limit was In experimental observations using actual GPS satellites, the ray paths encounter electrons not only in the ionospheric F layer but also in the hydrogendominated plasma of the protonosphere between 1100 km and the GPS altitude of 20200 km. A study using the SUPIM model of the potential influence of protonospheric electrons on GPS ray paths has been described by Lunt et al [1999a]. It was concluded that for observations at European midlafmdes at solar minimum, the electrons above l100 km only contributed a few TEC units to the total electron content.…”

Section: Resultsmentioning

confidence: 99%

“…It should be noted that while this condition may not always be valid for European observations at solar minimum, there are many circumstances in which the assumption can hold. The modeling studies of Lunt et al [1999a] showed that because of the tilt of the Earth's magnetic field, the fractional contribution to the electron content arising from the protonosphere was much smaller for observations at )unerican longitudes than for …”

Section: Discussionmentioning

confidence: 99%

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The effect of the protonosphere on the estimation of GPS total electron content: Validation using model simulations

Lunt¹,

Kersley²,

Bishop³

et al. 1999

Radio Science

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Abstract. Simulated observations of total electron cornera (TEC) along ray paths from Global Positiomng System (GPS) satellites have been used to validate the estimation of TEC using GPS measuremeres. The Sheffield Umversity plasmasphere ionosphere model (SUPIM) has been used to create electron densities that were integrated along ray paths from actual configurations of the GPS constellation. The resultant slant electron contents were then used as inputs to validate the self-calibration of pseudo-range errors (SCORE) process for the deternfination of TEC from GPS observations. It is shown that if the plasma resides only in the ionosphere below 1100 km, then the SCORE procedure determines the TEC to a high degree of accuracy. When the contribution of the electrons in the protonosphere above 1100 km is included, the analysis results in TEC estimates that are high by some 2 TEC umts (TECU) for conditions appropriate to European nfidlatimdes at solar nfimmum However, if a restriction is placed in the analysis on use of observations equatorward of the station, then allowance can be made for the effect of the proionosphere. It is shown that with appropriate selection of the boundary for the observations, TEC can be estimated by SCORE to better than 1 TECU for the conditions of the simulation. Sample results are included from actual experimemal observations using GPS to demonstrate the effect of compensation for the protonosphenc plasma.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The effect of the protonosphere on the estimation of GPS total electron content: Validation using model simulations

Lunt¹,

Kersley²,

Bishop³

et al. 1999

Radio Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…6) as expected from the latitude variation of PEC. Recently, Lunt et al (1999) estimated the plasmaspheric electron content in GPS ray paths at altitudes above 1100 km in the European and American sectors during magnetically quiet periods at low and high solar activities. According to their estimates, the European sector contains up to 4 TEC units of vertical PEC at 40…”

Section: Resultsmentioning

confidence: 99%

“…The difference between the two gives PEC (=TEC−IEC). There has been some arbitrariness in selecting the base altitude of the plasmasphere (Lunt et al, 1999) (Fig. 3(a)) to 780 km at midnight (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Doherty et al (1992) presented determinations of PEC along actual GPS ray paths, obtained from the difference between the GPS and Faraday rotation electron contents. Recently, Lunt et al (1999) estimated the values of PEC in the GPS ray paths at altitudes above 1100 km in European and American sectors. Gallagher et al (1988) presented an empirical model of the plasmasphere.…”

Section: Introductionmentioning

confidence: 99%

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Plasmaspheric electron content in the GPS ray paths over Japan under magnetically quiet conditions at high solar activity

et al. 2014

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Vertical total electron content (GPS-TEC) data obtained from the dual-frequency GPS receiver network (GEONET) in Japan are compared with those calculated using the Sheffield University plasmasphere-ionosphere model (SUPIM). The model is also used to estimate the electron content in the plasmaspheric sections of GPS ray paths for the three seasons of high solar activity (F10.7 = 165) under magnetically quiet conditions. According to the estimates, the plasmaspheric sections of vertical GPS ray paths over Japan at altitudes above the O + to H + transition height and above the upper altitude (2500 km) of Faraday rotation contain up to 11 and 9 TEC units (1 TEC unit = 10 16 electrons m −2 ) of free electrons, respectively. The free electrons present above the Faraday rotation altitude can cause propagation errors of up to 4.9 ns in time delay and 1.6 m in range at the GPS L1 (1.57542 GHz) frequency. The plasmaspheric electron content, PEC, changes appreciably with season and latitude and very little with the time of the day. However, the percentage contribution of PEC to GPS-TEC changes most significantly with the time of the day; the contribution varies from a minimum of about 12% during daytime at equinox to a maximum of about 60% at night in winter.

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An ensemble average method to estimate absolute TEC using radio beacon-based differential phase measurements: Applicability to regions of large latitudinal gradients in plasma density

et al. 2014

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A GNU Radio Beacon Receiver (GRBR) system for total electron content (TEC) measurements using 150 and 400 MHz transmissions from Low-Earth Orbiting Satellites (LEOS) is fabricated in house and made operational at Ahmedabad (23.04°N, 72.54°E geographic, dip latitude 17°N) since May 2013. This system receives the 150 and 400 MHz transmissions from high-inclination LEOS. The first few days of observations are presented in this work to bring out the efficacy of an ensemble average method to convert the relative TECs to absolute TECs. This method is a modified version of the differential Doppler-based method proposed by de Mendonca (1962) and suitable even for ionospheric regions with large spatial gradients. Comparison of TECs derived from a collocated GPS receiver shows that the absolute TECs estimated by this method are reliable estimates over regions with large spatial gradient. This method is useful even when only one receiving station is available. The differences between these observations are discussed to bring out the importance of the spatial differences between the ionospheric pierce points of these satellites. A few examples of the latitudinal variation of TEC during different local times using GRBR measurements are also presented, which demonstrates the potential of radio beacon measurements in capturing the large-scale plasma transport processes in the low-latitude ionosphere.

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The influence of the protonosphere on GPS observations: Model simulations

Cited by 79 publications

References 14 publications

The effect of the protonosphere on the estimation of GPS total electron content: Validation using model simulations

The effect of the protonosphere on the estimation of GPS total electron content: Validation using model simulations

Plasmaspheric electron content in the GPS ray paths over Japan under magnetically quiet conditions at high solar activity

An ensemble average method to estimate absolute TEC using radio beacon-based differential phase measurements: Applicability to regions of large latitudinal gradients in plasma density

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