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

Li, Wei; Cheng, Pengfei; Jinzhong, Bei; Wen, Hao; Wang, Hua

doi:10.1007/s12040-012-0206-6

Cited by 14 publications

(5 citation statements)

References 32 publications

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“…The average MAE values of MSF and TLI in the day are 1.0587 and 1.0779, respectively. In consideration of the observation errors in the real observations, the result accords with that of Li et al (2012). During the day, except for 12-13 UT, the MAE values of MSF are lower than TLI.…”

Section: Virtual Stec Assessmentsupporting

confidence: 80%

“…In NRTK, the virtual pseudorange and carrier phase observations of a VRS are generated with the observations of several nearby stations selected according to the distances and the azimuth angles (Zou et al 2013). In geomagnetically quiet days, the precision of the interpolated ionospheric delay is better than 10 cm, which is equivalent to about 0.951 TEC unit (TECU) (Li et al 2012). The interpolation accuracy of the double differenced ionospheric delay is even better than 1 cm in mid-latitudes and 2 cm in low latitudes (Tang et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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Virtual reference station-based computerized ionospheric tomography

Wan

et al. 2020

GPS Solut

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In computerized ionospheric tomography (CIT) with ground-based GNSS, the voxels without satellite-receiver ray traversing cannot be reconstructed directly. We present a CIT algorithm based on virtual reference stations (VRSs), called VRS–CIT, to decrease the number of unilluminated voxels and improve the precision of the estimated ionospheric electron density (IED). The VRSs are set at the nodes of grids with a 0.5° × 0.5° resolution in longitude and latitude. We generate the virtual observations with the observations from nearby six or three stations selected according to azimuths and distances. The generation utilizes multi-quadric surface fitting with six stations and triangular linear interpolation with three stations. With the virtual observations added, the IED distribution is reconstructed by the multiplicative algebraic reconstruction technique with the initial values obtained from IRI-2016. The performance of VRS–CIT is examined by using the data from 127 GNSS stations located in 24–46° N and 122–146° E to derive the IED every 30 min. The study focuses on April 29, 2014, with the adaptability of VRS–CIT analyzed by 12 days, evenly distributed around equinoxes and solstices of 2014. The accuracy of the virtual observation is about 1 TECU. Comparing to that derived from CIT with only real observations, the unsolvability of VRS–CIT declined by 4–12% for the whole region, and for the main area, the improvement can be up to 70%. Taking two IED profiles from radio occultation as reference measurements, the mean absolute error (MAE) of IED by VRS–CIT decreases by 6.88% and 8.43%, respectively. Comparing with slant total electron content (STEC) extracted from five additional GNSS stations, the MAE and the root mean square error of the estimated STEC can be reduced up to 17.24% and 33.81%, respectively.

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Section: Virtual Stec Assessmentsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Virtual reference station-based computerized ionospheric tomography

Wan

et al. 2020

GPS Solut

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“…Precise satellite orbit and clock offset products are indispensable in the PPP process. Generally, the precise satellite clock products published by the IGS are referred to an ionosphere‐free combination of satellite code hardware bias of the ionosphere‐free combined function model used in the precise satellite clock offset estimation (Wei et al, ; Zhang, Teunissen, et al, ). The biased satellite clock offset can be expressed as follows:

normald t_{I}^{T, S} = normald t^{T, S} + \frac{f_{1}^{2}}{f_{1}^{2} - f_{2}^{2}} b_{1}^{T, S} - \frac{f_{2}^{2}}{f_{1}^{2} - f_{2}^{2}} b_{2}^{T, S}

…”

Section: Methodsmentioning

confidence: 99%

“…However, there is a systematic arc‐dependent error (i.e., leveling error) that is induced by the code delay noise and multipath effects in the CCL‐based ionospheric observables. In this regard, some researchers have solved the leveling error by the precise point positioning (PPP) technique based on raw DF GNSS observations (Li et al, ; Wei et al, ; Zhang et al, ) and have obtained various noteworthy achievements. Zhang et al proposed a novel uncombined method based on SF PPP that enables the joint estimation of VTEC and SDCBs from raw GNSS observations (Li et al, ; Zhang, Teunissen, et al, ).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Retrieval of PWV and VTEC by Low‐Cost Multi‐GNSS Single‐Frequency Receivers

Zhao

Zhang

et al. 2019

Earth and Space Science

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Precipitable water vapor (PWV) and ionospheric vertical total electron content (VTEC) are two essential components of space‐atmosphere parameters. The zenith troposphere delay can be converted into PWV, which plays a crucial role in meteorological studies. In the meantime, the importance of the VTEC lies in providing ionospheric corrections for single‐frequency (SF) positioning, navigation, and timing users. Currently, the global navigation satellite system (GNSS) has become one of the most commonly used tools for retrieving PWV and VTEC and normally relies on dual‐frequency, geodetic‐grade receivers and antennas. However, this reliance also implies high hardware costs. In this paper, we propose a single‐frequency ionosphere and troposphere retrieval approach that enables the simultaneous retrieval of PWV and VTEC from multi‐GNSS data collected by low‐cost SF receivers. The use of SF receivers can greatly reduce the cost of hardware. Furthermore, the simultaneous provision of PWV and VTEC also has a positive effect on studying the coupling mechanisms of the ionosphere and troposphere. The accuracy of the estimated zenith troposphere delay can be better than 10 mm compared with the troposphere products published by the International GNSS Service, and the PWV is no more than 3 mm compared with radiosonde‐derived results. Referring to the final International GNSS Service global ionosphere map products and the Jason altimeter data, the VTEC retrieved from the single‐frequency ionosphere and troposphere retrieval method can perform at roughly equal levels compared to the customary dual‐frequency method.

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“…When sensing the ionosphere using a GNSS code and phase observations, the satellite and receiver differential code biases (DCBs) are one of the main sources of error in estimating the TEC [13,14]. By employing an ionospheric model, these biases in ionospheric observables can be extracted and calibrated [15][16][17]. Thus, the accuracy of the resulting STEC estimates is directly affected by the satellite and receiver DCB accuracies [18,19].…”

Section: Introductionmentioning

confidence: 99%

Epoch-Wise Estimation and Analysis of GNSS Receiver DCB under High and Low Solar Activity Conditions

et al. 2023

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Differential code bias (DCB) is one of the main errors involved in ionospheric total electron content (TEC) retrieval using a global navigation satellite system (GNSS). It is typically assumed to be constant over time. However, this assumption is not always valid because receiver DCBs have long been known to exhibit apparent intraday variations. In this paper, a combined method is introduced to estimate the epoch-wise receiver DCB, which is divided into two parts: the receiver DCB at the initial epoch and its change with respect to the initial value. In the study, this method was proved feasible by subsequent experiments and was applied to analyze the possible reason for the intraday receiver DCB characteristics of 200 International GNSS Service (IGS) stations in 2014 (high solar activity) and 2017 (low solar activity). The results show that the proportion of intraday receiver DCB stability less than 1 ns increased from 72.5% in 2014 to 87% in 2017, mainly owing to the replacement of the receiver hardware in stations. Meanwhile, the intraday receiver DCB estimates in summer generally exhibited more instability than those in other seasons. Although more than 90% of the stations maintained an intraday receiver DCB stability within 2 ns, substantial variations with a peak-to-peak range of 5.78 ns were detected for certain stations, yielding an impact of almost 13.84 TECU on the TEC estimates. Moreover, the intraday variability of the receiver DCBs is related to the receiver environment temperature. Their correlation coefficient (greater than 0.5 in our analyzed case) increases with the temperature. By contrast, the receiver firmware version does not exert a great impact on the intraday variation characteristics of the receiver DCB in this case.

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

Cited by 14 publications

References 32 publications

Virtual reference station-based computerized ionospheric tomography

Virtual reference station-based computerized ionospheric tomography

Simultaneous Retrieval of PWV and VTEC by Low‐Cost Multi‐GNSS Single‐Frequency Receivers

Epoch-Wise Estimation and Analysis of GNSS Receiver DCB under High and Low Solar Activity Conditions

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