A Worldwide Ionospheric Model for Fast Precise Point Positioning

Rovira‐Garcia, Adrià; Sanz, J.; González-Casado, Guillermo

doi:10.1109/tgrs.2015.2402598

Cited by 78 publications

(48 citation statements)

References 13 publications

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“…2018, 10, x FOR PEER REVIEW 9 of 13 from the stations used to derive the ionospheric model [6,30]. This is confirmed by comparing the results in Tables 6 and 7 for station BJFS and model EHRG and ESAG.…”

Section: Single-frequency Standard Point Positioning Experiments Testsupporting

confidence: 63%

“…Note that these accuracies may be a bit optimistic because the selected four stations are almost all used to generate the four GIM (except station BJFS in model EHRG). However, it is not critical that a particular station is (or not) used by a GIM, as once the GIMs are smoothed the accuracy is maintained up to few hundreds of kilometers from the stations used to derive the ionospheric model [6,30]. This is confirmed by comparing the results in Tables 6 and 7 for station BJFS and model EHRG and ESAG.…”

Section: Accuracy Assessment Of the Ionospheric Observablementioning

confidence: 62%

“…To model the temporal and spatial distribution of TEC, an ionospheric model with two layers at heights of 270 and 1600 km [30,40], a first layer to represent the ionosphere and a second layer representing the plasmasphere (or upper ionosphere), is used in this paper.…”

Section: Vertical Total Electron Content Modellingmentioning

confidence: 99%

“…The ESAG (European Space Agency GIM) and EHRG (European Space Agency Hourly Rapid GIM) are the GIMs provided by the IGS [38] and selected as background reference models for comparisons with the self-generated GIMs, specifically, the dual-layer Fast Precise Point Positioning (FPPP) [30,31] and a single-layer GIM named GAG1 (One-layer GIM based on the research group of Astronomy and Geomatics, gAGE products) that we created for the present study. Note: SH represents the spherical harmonic model, and G stands for GPS, R for GLONASS; IST represents the ionospheric stochastic tomography developed by (gAGE)/UPC [40] that has been improved in [6,30]. The spatial resolution is DLat × DLon, in degree unit.…”

Section: Experimental Data and Preprocess Strategymentioning

confidence: 99%

See 3 more Smart Citations

The Impacts of the Ionospheric Observable and Mathematical Model on the Global Ionosphere Model

Nie

Rovira‐Garcia

et al. 2018

Remote Sensing

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A high-accuracy Global Ionosphere Model (GIM) is significant for precise positioning and navigating with the Global Navigation Satellite System (GNSS), as well as space weather applications.To obtain a precise GIM, it is critical to take both the ionospheric observable and mathematical model into consideration. In this contribution, the undifferenced ambiguity-fixed carrier-phase ionospheric observable is first determined from a global distribution of permanent receivers. Accuracy assessment with a co-located station experiment shows that the observational errors affecting the ambiguity-fixed carrier-phase ionospheric observables range from 0.10 to 0.35 Total Electron Content Units (TECUs, where 1 TECU = 10 16 e − /m 2 and corresponds to 0.162 m on the Global Positioning System, GPS L1 frequency), indicating that the ambiguity-fixed carrier-phase ionospheric observable is over one order of magnitude more accurate than the carrier-phase leveled-code one (from 1.21 to 3.77 TECUs). Second, to better model the structure of the ionosphere, a two-layer GIM has been built based on the above carrier-phase observable. Preliminary global accuracy evaluation demonstrates that the accuracy of the two-layer GIM is below 1 TECU and about 2 TECUs during low and high solar activity periods. Third, the single-frequency point positioning experiment is adopted to test the ionosphere mitigation effects of the GIMs. Positioning results demonstrate that the single-frequency positioning accuracy can be improved by more than 30% using the undifferenced ambiguity-fixed ionospheric observable-derived two-layer GIM, compared with that using the carrier-phase leveled-code ionospheric observable-based single-layer GIM.

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Section: Single-frequency Standard Point Positioning Experiments Testsupporting

confidence: 63%

Section: Accuracy Assessment Of the Ionospheric Observablementioning

confidence: 62%

Section: Vertical Total Electron Content Modellingmentioning

confidence: 99%

Section: Experimental Data and Preprocess Strategymentioning

confidence: 99%

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The Impacts of the Ionospheric Observable and Mathematical Model on the Global Ionosphere Model

Nie

Rovira‐Garcia

et al. 2018

Remote Sensing

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“…The IGS final vertical total electron content (TEC) maps are used for the scientific analysis of the ionosphere and practical applications. However, the IGS final GIM product is released with a time delay of approximately 2 weeks, limiting their application in real-time scenarios, including real-time precise positioning (Shi et al 2012;Rovira-Garcia et al 2015) and space missions, such as the Soil Moisture and Ocean Salinity (SMOS) from the European Space Agency (ESA) (Silvestrin et al 2001;García-Rigo et al 2011). Rapid GIM products, e.g., UQRG (ftp://newg1.upc.es/upc_ ionex) and WHUD (ftp://pub.ionosphere.cn) provided by the Technical University of Catalonia (UPC) and Wuhan University (WHU), respectively, are available with oneday latency.…”

Section: Introductionmentioning

confidence: 99%

Prediction of global ionospheric VTEC maps using an adaptive autoregressive model

Wang

Xin

Liu

et al. 2018

Earth Planets Space

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In this contribution, an adaptive autoregressive model is proposed and developed to predict global ionospheric vertical total electron content maps (VTEC). Specifically, the spherical harmonic (SH) coefficients are predicted based on the autoregressive model, and the order of the autoregressive model is determined adaptively using the F-test method. To test our method, final CODE and IGS global ionospheric map (GIM) products, as well as altimeter TEC data during low and mid-to-high solar activity period collected by JASON, are used to evaluate the precision of our forecasting products. Results indicate that the predicted products derived from the model proposed in this paper have good consistency with the final GIMs in low solar activity, where the annual mean of the root-mean-square value is approximately 1.5 TECU. However, the performance of predicted vertical TEC in periods of mid-to-high solar activity has less accuracy than that during low solar activity periods, especially in the equatorial ionization anomaly region and the Southern Hemisphere. Additionally, in comparison with forecasting products, the final IGS GIMs have the best consistency with altimeter TEC data. Future work is needed to investigate the performance of forecasting products using the proposed method in an operational environment, rather than using the SH coefficients from the final CODE products, to understand the real-time applicability of the method.

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Ionospheric and plasmaspheric electron contents inferred from radio occultations and global ionospheric maps

et al. 2015

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We introduce a methodology to extract the separate contributions of the ionosphere and the plasmasphere to the vertical total electron content, without relying on a fixed altitude to perform that separation. The method combines two previously developed and tested techniques, namely, the retrieval of electron density profiles from radio occultations using an improved Abel inversion technique and a two-component model for the topside ionosphere plus protonosphere. Taking measurements of the total electron content from global ionospheric maps and radio occultations from the Constellation Observing System for Meteorology, Ionosphere, and Climate/FORMOSAT-3 constellation, the ionospheric and plasmaspheric electron contents are calculated for a sample of observations covering 2007, a period of low solar and geomagnetic activity. The results obtained are shown to be consistent with previous studies for the last solar minimum period and with model calculations, confirming the reversal of the winter anomaly, the hemispheric asymmetry of the semiannual anomaly, and the existence in the plasmasphere of an annual anomaly in the South American sector of longitudes. The analysis of the respective fractional contributions from the ionosphere and the plasmasphere to the total electron content shows quantitatively that during the night the plasmasphere makes the largest contribution, peaking just before sunrise and during winter. On the other hand, the fractional contribution from the ionosphere reaches a maximum value around noon, which is nearly independent of season and geomagnetic latitude.

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A Worldwide Ionospheric Model for Fast Precise Point Positioning

Cited by 78 publications

References 13 publications

The Impacts of the Ionospheric Observable and Mathematical Model on the Global Ionosphere Model

The Impacts of the Ionospheric Observable and Mathematical Model on the Global Ionosphere Model

Prediction of global ionospheric VTEC maps using an adaptive autoregressive model

Ionospheric and plasmaspheric electron contents inferred from radio occultations and global ionospheric maps

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