Generation of Assimilated Indian Regional Vertical TEC Maps

Harsha, P. Babu Sree; Dabbakuti, J. R. K. Kumar

doi:10.1007/s10291-019-0934-z

Cited by 11 publications

(8 citation statements)

References 33 publications

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“…Additionally, SAKARMA model is also validated for both the geomagnetic quiet and disturbed days during 1-30 September of 2016 using the AIRAVAT maps and 2-12 September 2017 years using the NAVIC observations respectively. The VTEC maps from AIRAVAT are considered as it is data assimilation technique based on Kalman filer using the regional ionospheric space weather data from space and ground-based satellite observations over India [18]. Thus, AIRAVAT VTEC maps facilitated to evaluate the performance of the SAKARMA model on the spatial basis over Indian region.…”

Section: Resultsmentioning

confidence: 99%

“…The VTEC maps generated from Assimilated Indian Regional Vertical TEC (AIRAVAT) covers the geographic latitudes from 5 • to 40 • and longitudes from 65 • to 100 • with spatial grid of 2.5 • latitude by 5 • longitude (120 grid points) over the Indian region with a temporal resolution of one hour (1 h) [18]. The VTEC data from AIRAVAT maps during 1-30 September 2016 is considered to validate the SAKARMA model.…”

Section: Data and Proposed Ionospheric Sakarma Modelmentioning

confidence: 99%

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A New Ionospheric Model for Single Frequency GNSS User Applications Using Klobuchar Model Driven by Auto Regressive Moving Average (SAKARMA) Method Over Indian Region

et al. 2020

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The single-frequency users of Global Navigation Satellite System (GNSS) require an effective mathematical model that mitigate the dominant errors due to ionospheric delays. Klobuchar model approximately reduces ionospheric effect up to 50% through its coefficients in the navigation message, which is not sufficient for the GNSS single frequency users at critical applications. Hence, a new model, for Single Frequency GNSS User Applications using Klobuchar model driven by Auto Regressive Moving Average Method (SAKARMA) is proposed to forecast and enhance the precision of ionospheric delay estimations for GNSS users. The hourly VTEC maps are obtained from the Assimilated Indian Regional Vertical Total Electron Content (AIRAVAT) by the process of data assimilation using the Kalman filter exclusively for the Indian region (longitude: 65 • E to 100 • E; latitude: 5 • N to 40 • N) using 26 GPS TEC stations over Indian region. The accuracy of the SAKARMA model is investigated using the AIRAVAT maps for various Indian geographic regions during both geomagnetic quiet and disturbed conditions of September month in 2016 year. Furthermore, in order to test SAKARMA model, a dual-frequency Navigation with Indian Constellation (NavIC) receiver located at the KL Education Foundation, Guntur, India (geographic: 16.37 • N, 80.37 • E; geomagnetic: 7.44 • N, 153.75 • E) is used to collect the observations during 2-12 September 2017. Furthermore, SAKARMA model is also validated with Klobuchar model, Klobuchar-style coefficients provided by the Center for Orbit Determination in Europe (CODE) (CODKlob) Model, BeiDou System (BDS2) Model and NeQuick 2 Model over a low latitude NavIC station in forecasting the ionospheric delays. The experimental results of SAKARMA for NavIC have revealed that the MAPE for proposed SAKARMA model is 9-17% (accuracy: 83-91%), while 34-53% (accuracy: 47-66%) for the Klobuchar model. Thus, the results illustrate that the proposed SAKARMA model is capable of predicting the ionospheric delays for single frequency GNSS/NavIC users. INDEX TERMS GNSS, NavIC, ionospheric delay, Klobuchar model, auto regressive moving average (ARMA) model, SAKARMA model. The associate editor coordinating the review of this manuscript and approving it for publication was Halil Ersin Soken .

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Section: Resultsmentioning

confidence: 99%

Section: Data and Proposed Ionospheric Sakarma Modelmentioning

confidence: 99%

A New Ionospheric Model for Single Frequency GNSS User Applications Using Klobuchar Model Driven by Auto Regressive Moving Average (SAKARMA) Method Over Indian Region

et al. 2020

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“…The performance of the 4 th order ASHF model evaluated CODE-GIM model. To generate reference TEC maps by Assimilated Indian Regional Vertical Total Electron Content (AIRAVAT) model [17]. Fig.…”

Section: A Comparison Of 4 Th Order Ashf Model With Dual-frequency Tmentioning

confidence: 99%

“…Large temporal and spatial gradients in the ionospheric delay s are significant in the equatorial and low latitude regions [15], [16]. A regional ionospheric TEC model is necessary for modeling TEC data scattered over the region of interest [17]. SBAS Ionospheric Grid-based models are generally used to estimate the ionospheric delays at the predefined ionospheric grid points and provide the values to the users [18].…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of Adjusted Spherical Harmonics Ionospheric Model Over Indian Region

et al. 2020

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The ionosphere is perceived to be a predominant source of ranging error of Global Navigation Satellite System (GNSS) signals to degrade the positional accuracy. The suitable ionospheric model is necessary to improve the positional accuracy of GNSS and Satellite-Based Augmentation System (SBAS) users. In this paper, the regional ionospheric model (RIM) over the Indian region is implemented based on the adjusted spherical harmonics function (ASHF) model from dense GPS TEC stations over the Indian region. Also, the evaluation of the different ASHF order models conducted to identify the proper order of the ASHF model for Indian low latitude ionospheric calm and adverse space weather conditions. The results confirm that the 4 th order ASHF ionospheric model can identify the northern Equatorial Ionization Anomaly (EIA) TEC crest patterns over the Indian region. The comparison of the 4 th order ASHF ionospheric model carried out with dual and single frequency ionospheric models like as Klobuchar model, Centre for Orbit Determination in Europe (CODE) Klobuchar model, NeQuick G model, BeiDou System (BDS2) model and CODE Global Ionospheric Maps (GIM) models. The outcome of the results indicates that the 4 th Order ASHF ionospheric model would be potential for single and dual-frequency ionospheric models for GNSS and SBAS systems. INDEX TERMS Ionosphere, Total Electron Content (TEC), GPS Aided GEO Augmented Navigation(GAGAN), Adjusted Spherical Harmonics Function (ASHF).

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“…Tulasi Ram et al [24] noticed the enhanced zonal electric field in response to prompt penetration electric field during 17 th March 2015. Pasumarthi and Devanaboyina [26] also proposed Assimilated Indian Regional Vertical TEC (AIRAVAT) maps for Indian region using Kalman filter data assimilation approach using Centre for Orbit Determination in Europe (CODE) Global Ionospheric Maps (GIM) for quiet and disturbed day conditions. Nevertheless, influence of solar, geomagnetic indices along with electric field parameters on regional TEC models during geomagnetic storm conditions is needed.…”

Section: Introductionmentioning

confidence: 99%

Generation of Regional Ionospheric TEC Maps With EIA Nowcasting/Forecasting Capability During Geomagnetic Storm Conditions

Harsha

Ratnam

2020

IEEE Access

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In this paper, ground based Global Positioning System (GPS) Total Electron Content (TEC) observations collected from the GPS Aided GEO Augmented Navigation (GAGAN) network over low latitude Indian subcontinent are assimilated into the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM). Gauss-Markov Kalman filter methodology is utilized and the background model error covariance (BMEC) matrix is framed using solar, geomagnetic, cross tail potential and hemispheric power indices using multivariate principal component analysis (MPCA) method. The model variations through different high latitude electric field models (Weimer and Heelis) are utilized in the data assimilation analysis. The proper attempt is modeled for providing TEC forecasts during geomagnetic storm conditions from 15 th to 20 th March 2015 days over Indian region. The more concentration is given in understanding the equatorial ionization anomaly (EIA) characteristics during the initial, main and recovery phase of St. Patrick's Day March 2015 geomagnetic storm. The proposed model forecast outperforms the persistence forecast with maximum forecast score (1.6) and forecast skill (2.2) during recovery phase of storm. TEC forecasts are validated with current time step GPS observations and 93 % correlation is observed on quiet day (10 th March 2015) and 82 % correlation is noticed on main phase of storm (17 th March 2015). Also proposed TEC model analysis and forecast results are compared with International Global Navigation Satellite Service (IGS) TEC stations datasets. A clear negative storm effect (EIA inhibition) has been forecasted well with the proposed Kalman filter and MPCA methodology aspects.

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Generation of Assimilated Indian Regional Vertical TEC Maps

Cited by 11 publications

References 33 publications

A New Ionospheric Model for Single Frequency GNSS User Applications Using Klobuchar Model Driven by Auto Regressive Moving Average (SAKARMA) Method Over Indian Region

A New Ionospheric Model for Single Frequency GNSS User Applications Using Klobuchar Model Driven by Auto Regressive Moving Average (SAKARMA) Method Over Indian Region

Performance Evaluation of Adjusted Spherical Harmonics Ionospheric Model Over Indian Region

Generation of Regional Ionospheric TEC Maps With EIA Nowcasting/Forecasting Capability During Geomagnetic Storm Conditions

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