Refining the Klobuchar ionospheric coefficients based on GPS observations

Yuan, Yunbin; Huo, Xingliang; Ou, Junfei; Zhang, Kefei; Chai, Yanwei; Wen, Duancheng; Grenfell, R.

doi:10.1109/taes.2008.4667725

Cited by 68 publications

(30 citation statements)

References 15 publications

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“…The receiver DCB of one specific antenna is assumed to be stable and is set as a constant for one day [17], [19], [21]- [23]. Piecewise constant processing is adopted in the estimation of spherical harmonic coefficients, and the time spacing is set according to the spatial and temporal distributions of the observations.…”

Section: Methodsmentioning

confidence: 99%

Daily Global Plasmaspheric Maps Derived From COSMIC GPS Observations

Zhang

Tang

2014

IEEE Trans. Geosci. Remote Sensing

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GPS precise orbit determination antenna observations from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites represent a new plasmaspheric data source, which are globally distributed and continuously available. By assuming that all free electrons in the plasmasphere at an altitude range of approximately 800-20 200 km are contained in a thin shell (namely, a single-layer model), daily global plasmaspheric maps (GPMs) of plasmaspheric electron content (PEC) are constructed using a spherical harmonic expansion. We employ this method to obtain PEC maps for DOY 102-131 in 2008 and compare the PEC model values with the Meteorological Operational satellite programme (MetOp) measurements. According to the estimation results, the global PEC values show features that are consistent with previous studies and exhibit higher estimation accuracy; the estimation results of COSMIC GPS receiver differential code biases also agree well with the reference values in the 30 days. During this period, the mean rms of the differences between MetOp PEC measurements and GPM PEC values is 1.29 TECU, which suggests that GPMs can offer reasonable and high-precision PEC values.

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Section: Methodsmentioning

confidence: 99%

Daily Global Plasmaspheric Maps Derived From COSMIC GPS Observations

Zhang

Tang

2014

IEEE Trans. Geosci. Remote Sensing

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“…This corresponds to a range error of about 0.56 m on the GPS L1 frequency. In comparison, Yuan et al (2008a) developed a method to update the Klobuchar model coefficients by GPS observations. The approach was validated with independent ionospheric delays during the quiet period of 1-8 January 2001.…”

Section: Validation With Independent Ground-based Stec Datamentioning

confidence: 99%

Simultaneous multiplicative column-normalized method (SMART) for 3-D ionosphere tomography in comparison to other algebraic methods

Gerzen

Minkwitz

2016

Ann. Geophys.

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Abstract. The accuracy and availability of satellite-based applications like GNSS positioning and remote sensing crucially depends on the knowledge of the ionospheric electron density distribution. The tomography of the ionosphere is one of the major tools to provide link specific ionospheric corrections as well as to study and monitor physical processes in the ionosphere.In this paper, we introduce a simultaneous multiplicative column-normalized method (SMART) for electron density reconstruction. Further, SMART+ is developed by combining SMART with a successive correction method. In this way, a balancing between the measurements of intersected and not intersected voxels is realised. The methods are compared with the well-known algebraic reconstruction techniques ART and SART. All the four methods are applied to reconstruct the 3-D electron density distribution by ingestion of ground-based GNSS TEC data into the NeQuick model.The comparative case study is implemented over Europe during two periods of the year 2011 covering quiet to disturbed ionospheric conditions. In particular, the performance of the methods is compared in terms of the convergence behaviour and the capability to reproduce sTEC and electron density profiles. For this purpose, independent sTEC data of four IGS stations and electron density profiles of four ionosonde stations are taken as reference. The results indicate that SMART significantly reduces the number of iterations necessary to achieve a predefined accuracy level. Further, SMART+ decreases the median of the absolute sTEC error up to 15, 22, 46 and 67 % compared to SMART, SART, ART and NeQuick respectively.

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“…For this purpose, Eq. (18) is expanded by the Taylor series expansion [9] around the approximationsα n andβ n , and the second and higher order terms are neglected. Then the linearized equation of Eq.…”

Section: Refining Parameters α and βmentioning

confidence: 99%

Refining the Klobuchar Ionospheric Model with Spherical Cap Harmonic Model for GNSS Positioning

Nishimoto

Ohashi

Kubo

et al. 2013

Stochastic Systems Theory and its Applications (SSS)

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Ionospheric delay is one of the major error sources in GNSS (Global Navigation Satellite System) positioning. For single frequency system, it is very important to effectively correct the ionospheric delay and so-called Klobuchar's ionospheric model has been widely used due to its well known properties such as computational simplicity. The Klobuchar model is one of the global ionospheric models, and it can correct about 50% RMS ionospheric errors [1]. On the other hand, there are some models that can achieve better accuracy than the Klobuchar model, the SCHA (Spherical Cap Harmonics Analysis) model is one of such models. By the SCHA model, it has been reported that the ionospheric delays can be well modeled in the regional area such as the sky over Japan [2]. However, comparing with the Klobuchar model, the SCHA model needs more number of parameters and computational burden. Therefore, in this paper, a method to generate the parameters of the Klobuchar model from the SCHA model is proposed. By this method, the regional ionospheric model that is not only simple and easy operational like the Klobuchar model but also regionally accurate like the SCHA model is obtained.

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Refining the Klobuchar ionospheric coefficients based on GPS observations

Cited by 68 publications

References 15 publications

Daily Global Plasmaspheric Maps Derived From COSMIC GPS Observations

Daily Global Plasmaspheric Maps Derived From COSMIC GPS Observations

Simultaneous multiplicative column-normalized method (SMART) for 3-D ionosphere tomography in comparison to other algebraic methods

Refining the Klobuchar Ionospheric Model with Spherical Cap Harmonic Model for GNSS Positioning

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