Ionospheric tomographic common clock model of undifferenced uncombined GNSS measurements

Olivares‐Pulido, Germán; Hernández‐Pajares, Manuel; Lyu, Haixia; Gu, Shengfeng; Rigo, Alberto Garcıa; Graffigna, Victoria; Tomaszewski, Dariusz; Wielgosz, Paweł; Rapiński, Jacek; Krypiak-Gregorczyk, Anna; Kaźmierczak, Rafał; Orús‐Pérez, Raül

doi:10.1007/s00190-021-01568-8

Cited by 4 publications

(4 citation statements)

References 22 publications

(36 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The tomographic model fixes the rank deficit of Equations ( 1) and ( 2) by decorrelating the ionospheric delay from the ambiguity term [4]. Vertical Total Electron Content (VTEC) models also fix the rank, but then the ionospheric gradient mismodeling increases with the baseline.…”

Section: The Wartk Modelmentioning

confidence: 99%

“…However, it takes at least half an hour to fix the ambiguity term for PPP algorithms. In order to reduce the computational time for ambiguity fixing, external corrections for the ionospheric term are required [3,4]. There are several methods that use the ionospheric information for GNSS algorithms to converge faster, e.g., undifferenced and uncombined methods, such as PPP-RTK [5][6][7], but also undifferenced and combined methods such as WARTK [1].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wide-Area GNSS Corrections for Precise Positioning and Navigation in Agriculture

Hernández‐Pajares¹,

Olivares‐Pulido²,

Graffigna³

et al. 2022

Remote Sensing

Self Cite

View full text Add to dashboard Cite

This paper characterizes, with static and roving GNSS receivers in the context of precision agriculture research, the hybrid ionospheric-geodetic GNSS model Wide-Area Real-Time Kinematics (WARTK), which computes and broadcasts real-time corrections for high-precision GNSS positioning and navigation within sparse GNSS receiver networks. This research is motivated by the potential benefits of the low-cost precise WARTK technique on mass-market applications such as precision agriculture. The results from two experiments summarized in this work, the second one involving a working spraying tractor, show, firstly, that the corrections from the model are in good agreement with the corrections provided by IGS (International GNSS Services) analysis centers computed in post-processing from global GNSS data. Moreover, secondly and most importantly, we have shown that WARTK provides navigation solutions at decimeter-level accuracy, and the ionospheric corrections significantly reduce the computational time for ambiguity estimation: up to convergence times for the 50%, 75% and 95% of cases equal or below 30 s (single-epoch), 150 s and 600 s approximately, vs. 1000 s, 2750 s and 4850 s without ionospheric corrections, everything for a roving receiver at more than 100 km far away from the nearest permanent receiver. The real-time horizontal position errors reach up to 3 cm, 5 cm and 12 cm for 50%, 75% and 95% of cases, respectively, by constraining and continuously updating the ambiguities without updating the permanent receiver coordinates, vs. the 6 cm, 12 cm and 32 cm, respectively, in the same conditions but without WARTK ionospheric corrections.

show abstract

Section: The Wartk Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wide-Area GNSS Corrections for Precise Positioning and Navigation in Agriculture

Hernández‐Pajares¹,

Olivares‐Pulido²,

Graffigna³

et al. 2022

Remote Sensing

Self Cite

View full text Add to dashboard Cite

show abstract

“…This paper is organized as follows. In Section 2, we will describe all the three datasets used for this work, as well as briefly introduce the software used for the computation, TOMION v2 [15,21]. Section 3 presents the analysis on the ZWD and its correspondence with rain data, followed by a new finding on the spectral components of the tropospheric gradients; and, finally, the relationship of the tropospheric gradients with atmospheric variables is discussed.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Study on the Tropospheric Wet Delay and Horizontal Gradients during a Severe Weather Event

et al. 2022

Self Cite

View full text Add to dashboard Cite

GNSS meteorology is today one of the most growing technologies to monitor severe weather events. In this paper, we present the usage of 160 GPS reference stations over the period of 14 days to monitor and track Hurricane Harvey, which struck Texas in August 2017. We estimate the Zenith Wet Delay (ZWD) and the tropospheric gradients with 30 s interval using TOMION v2 software and carry out the processing in Precise Point Positioning (PPP) mode. We study the relationship of these parameters with atmospheric variables extracted from Tropical Rainfall Measuring Mission (TRMM) satellite mission and climate reanalysis model ERA5. This research finds that the ZWD shows patterns related to the rainfall rate and to the location of the hurricane. We also find that the tropospheric gradients are correlated with water vapor gradients before and after the hurricane, and with the wind and the pressure gradients only after the hurricane. This study also shows a new finding regarding the spectral distribution of the gradients, with a clear diurnal period present, which is also found on the ZWD itself. This kind of study approaches the GNSS meteorology to the increasing requirements of meteorologist in terms of monitoring severe weather events.

show abstract

“…Obviously, the performance of the ionospheric delay model plays an important role in the ionosphere constrained undifferenced uncombined PPP (e.g. Olivares-Pulido et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Quasi-4-dimension ionospheric modeling and its application in PPP

Gan

et al. 2022

Satell Navig

Self Cite

View full text Add to dashboard Cite

Ionospheric delay modeling is not only important for Global Navigation Satellite System (GNSS) based space weather study and monitoring, but also an efficient tool to speed up the convergence time of Precise Point Positioning (PPP). In this study, a novel model, denoted as Quasi-4-Dimension Ionospheric Modeling (Q4DIM) is proposed for wide-area high precision ionospheric delay correction. In Q4DIM, the Line Of Sight (LOS) ionospheric delays from a GNSS station network are divided into different clusters according to not only the location of latitude and longitude, but also satellite elevation and azimuth. Both Global Ionosphere Map (GIM) and Slant Ionospheric Delay (SID) models that are traditionally used for wide-area and regional ionospheric delay modeling, respectively, can be regarded as the special cases of Q4DIM by defining proper grids in latitude, longitude, elevation, and azimuth. Thus, Q4DIM presents a resilient model that is capable for both wide-area coverage and high precision. Four different sets of clusters are defined to illustrate the properties of Q4DIM based on 200 EUREF Permanent Network (EPN) stations. The results indicate that Q4DIM is compatible with the GIM products. Moreover, it is proved that by inducting the elevation and azimuth angle dependent residuals, the precision of the 2-dimensional GIM-like model, i.e., Q4DIM 2-Dimensional (Q4DIM-2D), is improved from around 1.5 Total Electron Content Units (TECU) to better than 0.5 TECU. In addition, treating Q4DIM as a 4-dimensional matrix in latitude, longitude, elevation, and azimuth, whose sparsity is less than 5%, can result in its feasibility in a bandwidth-sensitive applications, e.g., satellite-based Precising Point Positioning Real-Time Kinematic (PPP-RTK) service. Finally, the advantages of Q4DIM in PPP over the 2-dimensional models are demonstrated with the one month's data from 30 EPN stations in both high solar activity year 2014 and low solar activity year 2020.

show abstract

Ionospheric tomographic common clock model of undifferenced uncombined GNSS measurements

Cited by 4 publications

References 22 publications

Wide-Area GNSS Corrections for Precise Positioning and Navigation in Agriculture

Wide-Area GNSS Corrections for Precise Positioning and Navigation in Agriculture

Comprehensive Study on the Tropospheric Wet Delay and Horizontal Gradients during a Severe Weather Event

Quasi-4-dimension ionospheric modeling and its application in PPP

Contact Info

Product

Resources

About