A new ionospheric tomographic algorithm — constrained multiplicative algebraic reconstruction technique (CMART)

Wen, Desheng; Liu, Sanzhi

doi:10.1007/s12040-010-0039-0

Cited by 13 publications

(6 citation statements)

References 10 publications

(8 reference statements)

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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%

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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%

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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“…As is known, CIT involves illposed inversion because of the limitation of the observational elevation angles and the low coverage of the GPS signal rays leading to the rank defect of formula (1) (Choi et al 2006;Wen et al 2007). To decrease its ill-condition, some improvement strategies (e.g., providing enough and evenly distributed GPS tracking stations) should be incorporated before reconstruction by MART (Yeh and Raymund 1991;Wen and Liu 2010). In this study, we pick out 38 evenly distributed tracking stations of CMONOC in the reconstruction area to improve the reconstruction accuracy.…”

Section: Resultsmentioning

confidence: 99%

Possible seismo-ionospheric precursor of the 12 February 2014 Yutian earthquake in China

et al. 2019

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, a major earthquake occurred near the Yutian County, China. In this paper, the ionospheric variations around the time of this earthquake were analysed on the basis of the global positioning system vertical total electron contents (VTEC) and computerised ionospheric tomography (CIT) electron density distributions. Three ionospheric anomalies on 2, 17 and 19 February were detected with the global VTEC data from Center for Orbit Determination in Europe before and after the earthquake. Based on the analysis of the geomagnetic indices, we think the anomalies on 17 and 19 February could be related to the geomagnetic disturbances. Through further investigations on the temporal and spatial characteristics of the anomaly on 2 February, we draw the conclusion that the preearthquake ionospheric anomaly is probably the seismo-ionospheric precursor of the Yutian earthquake. In addition, the CIT results of the anomaly on 2 February were used to study the vertical distribution of this anomaly. The results showed that the ionospheric anomaly was mainly concentrated at the heights between 200 and 400 km.

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“…produces nonnegative values, so an advantage of using MART, instead of ART or SART, is the guarantee of nonnegative values for electron density. Many new iterative algorithms are being developed to improve algebraic techniques; however, most of them are based on the principles of ART, SART, or MART (Hobiger et al 2008;Wen and Liu 2010;Wen et al 2012).…”

Section: Tomographic Formulationmentioning

confidence: 99%

Ionospheric tomography using GNSS: multiplicative algebraic reconstruction technique applied to the area of Brazil

Prol

Camargo

2015

GPS Solut

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Experimental analysis was performed using multiplicative algebraic reconstruction technique (MART) to map the ionosphere over Brazil. Code and phase observations from the global navigation satellite system (GNSS) together with the international reference ionosphere (IRI) enabled the estimation of ionospheric profiles and total electron content (TEC) over the entire region. Twenty-four days of data collected from existing groundbased GNSS receivers during the recent solar maximum period were used to analyze the performance of the MART algorithm. The results were compared with four ionosondes. It was demonstrated that MART estimated the electron density peak with the same degree of accuracy as the IRI model in regions with appropriate geometrical coverage by GNSS receivers for tomographic reconstruction. In addition, the slant TEC, as estimated with MART, presented lower root-mean-square error than the TEC calculated by ionospheric maps available from the International GNSS Service (IGS). Furthermore, the daily variations of the ionosphere were better represented with the algebraic techniques, compared to the IRI model and IGS maps, enabling a correlation of the elevation of the ionosphere at higher altitudes with the equatorial ionization anomaly intensification. The tomographic representations also enabled the detection of high vertical gradients at the same instants in which ionospheric irregularities were evident.

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A new ionospheric tomographic algorithm — constrained multiplicative algebraic reconstruction technique (CMART)

Cited by 13 publications

References 10 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

Possible seismo-ionospheric precursor of the 12 February 2014 Yutian earthquake in China

Ionospheric tomography using GNSS: multiplicative algebraic reconstruction technique applied to the area of Brazil

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