Two-Shell Ionospheric Model for Indian Region: A Novel Approach

Shukla, Ashish; Das, Saurabh; Nagori, Neha; Sivaraman, M. R.; Bandyopadhyay, K.

doi:10.1109/tgrs.2009.2017520

Cited by 34 publications

(18 citation statements)

References 12 publications

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“…However, the single shell model may not give reliable estimate of vTEC when the satellite elevation angle is less than 50 degree. If a larger and denser regional network is chosen, it could be replaced by advanced tomography (Shukla et al 2009(Shukla et al , 2010Wen and Liu 2010).…”

Section: Discussionmentioning

confidence: 99%

“…It is well known that the ionosphere is a dominant error source for single-frequency GPS users (Klobuchar 1987;Goad 1990; Brunini and Azpilicueta 2010). Many models have been developed to mitigate this error, e.g., the Kolbuchar model (Klobuchar 1987), grid-based models (Mannucci et al 1998;Walter et al 2000;Dow et al 2005) and tomographic models (Ruffini et al 1998;Shukla et al 2009Shukla et al , 2010Wen and Liu 2010). One prerequisite for the above ionosphere models is the extraction of ionospheric observables from dual frequency GPS observations (Wilson and Mannucci 1994;Burrell et al 2006;Rideout and Coster 2006); this is commonly achieved using the phase-smoothed pseudorange (PSP) method (Coco et al 1991;Sardon et al 1994).…”

Section: Introductionmentioning

confidence: 99%

“…This assumption model reduces a three-dimensional problem to a two dimensional; however, the assumption is unrealistic and might result in modeling errors (Smith et al 2008;Brunini and Azpilicueta 2010). Therefore, several modified ionospheric models, such as tomographic models (Shukla et al 2009(Shukla et al , 2010Das and Shukla 2011), have been exploited.…”

Section: Introductionmentioning

confidence: 99%

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Calibration of regional ionospheric delay with uncombined precise point positioning and accuracy assessment

Cheng

Jinzhong

et al. 2012

J Earth Syst Sci

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A new method for the calibration of regional ionospheric delay based on uncombined precise point positioning (U-PPP) is proposed in this study. The performance of the new method was comparatively validated in terms of its accuracy and robustness with respect to the phase-smoothed pseudorange (PSP) method through two short-baseline experiments. Accuracy of the PPP-derived ionospheric delays was further assessed by interpolating them to a user station to perform single-frequency simulated kinematic PPP. Two 24-hr period datasets of four continuous operation reference system (CORS) stations were analyzed, collected during calm and disturbed ionospheric conditions, respectively. The single-frequency GPS observables from a user station, that were a-priori corrected by the interpolated ionospheric delays, were utilized to implement single-frequency PPP (SF-PPP). The results show that interpolation accuracy is better than 1 dm and, with the proposed method, is less affected by the ionospheric activity; meanwhile, positioning accuracy of SF-PPP was 4∼5 cm (horizontal) and better than 1 dm (vertical). For comparison, two reference SF-PPP solutions were also obtained, in which the ionospheric delays are eliminated either by forming semi-combination observations or by using global ionosphere maps (GIM) model values; in both cases the positioning accuracy was only 4∼7 dm (horizontal) and 1 m (vertical). These results provide a further demonstration of the performance of PPP-based regional ionospheric calibration in the parameter domain.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Calibration of regional ionospheric delay with uncombined precise point positioning and accuracy assessment

Cheng

Jinzhong

et al. 2012

J Earth Syst Sci

View full text Add to dashboard Cite

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“…This is therefore coincident with the maximum plasma concentration of the F 3 layer, which occurs above the ionospheric F 2 layer at about 550 km before noon [8]. A two-shell model with the ionosphere assumed to exist at two different heights at 300-and 500-km altitudes is also suggested for the ground-based GPS users in the EIA belt [31]. In addition, a simple trigonometric function is considered as the ionospheric mapping function [32].…”

Section: A Ionospheric Single-layer Model and Mapping Functionmentioning

confidence: 81%

Monitoring the Daytime Variations of Equatorial Ionospheric Anomaly Using IONEX Data and CHAMP GPS Data

Huo

Yuan

et al. 2011

IEEE Trans. Geosci. Remote Sensing

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A method, which can invert the ionospheric electron content above the CHAMP satellite, is presented. The daytime behavior of the equatorial ionospheric anomaly (EIA) is monitored using the CHAMP global positioning system data and the ionosphere map exchange format data supplied by the Center for Orbit Determination in Europe during the period at quiet geomagnetic conditions between November 7 and December 12, 2003. Results show that the plasma congregates and rises above the geomagnetic equator due to the daytime upward vertical E × B drift during the early variations of EIA. After being lifted to higher altitudes, the topside ionospheric equatorial plasma above the CHAMP orbit (over 400 km above the ground) controlled mainly by the electromagnetic field starts to diffuse downward to higher latitudes along magnetic field lines, and the double-humped structure begins to appear in the topside ionosphere above the CHAMP orbit. However, a single crest is still observed for the entire ionosphere above the ground, and this single peak moves slightly to the winter hemisphere as a result of the transequatorial neutral wind. With the continuous diffusion of the plasma, the two crests also occur for the entire ionosphere at both sides of the geomagnetic equator.Index Terms-CHAMP, equatorial ionospheric anomaly (EIA), global positioning system (GPS), ionosphere map exchange (IONEX).

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“…The global models such as the IRI-2007 model, Klobuchar model and so on, are applicable across the world for civilian applications. The regional models such as the inverse distance weighted model, spherical harmonic function model, two-shell ionospheric model and so on, have better accuracy than that of the global models and are applicable to a particular region of interest [8][9][10][11][12][13][14]. The local models such as the TSE model, global navigation satellite system (GNSS) regression model and so on, are applicable to a very limited area, where the local model is the sub-set of the regional model and is expected to perform better than a regional model [15,16].…”

Section: Ionospheric Modelsmentioning

confidence: 99%

Modelling of ionospheric time delay of Global Positioning System (GPS) signals using Taylor series expansion for GPS Aided Geo Augmented Navigation applications

Kumar¹,

Sarma

Ammana

2014

IET Radar, Sonar & Navigation

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The positional accuracy of Indian Global Positioning System Aided Geo Augmented Navigation (GAGAN) system is affected by many errors and among them the ionospheric time delay error is the predominant error. The Indian ionosphere is characterised by large gradients, intense irregularities and equatorial anomaly conditions and hence suitable ionospheric model is necessary for GAGAN. Compared with global and regional ionospheric models, not much significant work is reported on local ionospheric models for Indian region. In this study, using Indian Satellite Based Augmentation System data, a local ionospheric model based on Taylor series expansion (TSE) is used. Initially, a network of 17 GAGAN total electron content stations data are considered in the analysis for both quiet and disturbed days. The ionospheric time delay results of the TSE model indicate that the model is performing better for quiet days than the disturbed days. The delay because of the TSE model is compared with that of the delays because of Klobuchar and IRI-2007 models and experimental GAGAN data. The obtained results shows that the TSE model is estimating delay more closely with respect to GAGAN data than that of the Klobuchar and IRI-2007 models and may be considered for use in offline applications.

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Two-Shell Ionospheric Model for Indian Region: A Novel Approach

Cited by 34 publications

References 12 publications

Calibration of regional ionospheric delay with uncombined precise point positioning and accuracy assessment

Calibration of regional ionospheric delay with uncombined precise point positioning and accuracy assessment

Monitoring the Daytime Variations of Equatorial Ionospheric Anomaly Using IONEX Data and CHAMP GPS Data

Modelling of ionospheric time delay of Global Positioning System (GPS) signals using Taylor series expansion for GPS Aided Geo Augmented Navigation applications

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