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PPP Without Troposphere Estimation: Impact Assessment of Regional Versus Global Numerical Weather Models and Delay Parametrization

  • Thalia NikolaidouEmail author
  • Felipe Nievinski
  • Kyriakos Balidakis
  • Harald Schuh
  • Marcelo Santos
Conference paper
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 149)

Abstract

Mapping functions based on global Numerical Weather Models (NWM) have been developed in recent years to model the tropospheric delay in space geodetic techniques such as the Global Navigation Satellite Systems (GNSS). However, the estimation of residual tropospheric delay is still a necessity when high accuracy is required. Additionally, correlation between the estimated tropospheric delay, the receiver clock offset and the station height component, prolongs the time required for the solution to converge and impacts directly the accuracy of the results. In this study, we applied tropospheric corrections from high resolution NWM in GPS processing, in an attempt to acquire rapid and accurate positioning results, waiving the need to estimate residual tropospheric delay. Although high resolution NWM have outperformed standard atmosphere parameters and global models, it is the first time they have been compared against NWM-derived corrections, such as the operational Vienna Mapping Function 1 (VMF1) parameters. The processing strategy employed utilizes different scenarios characterized by their (a) NWM temporal and spatial resolution (b) grid or site-specific domain and (c) delay parametrization. The results were assessed in terms of height components bias, convergence frequency and time as well as residuals of the GPS analysis. Results showed an overall scenarios agreement of about 20 cm for the height component. However, the site-specific domain and high resolution NWM scenarios outperformed the grid-based ones in most of the cases; centimeter compared to decimeter daily height time series bias along faster convergence time constituted their performance. The final height offset with respect to their ITRF14 values was almost three times larger for the grid-based scenarios compared to the site-specific ones. The iono-free least squares adjustment residuals analysis revealed similar patterns for all the scenarios while the estimated heights experienced a reduction on the days of heavy precipitation under most of the scenarios; for some of the stations the advantage of using direct ray-tracing became obvious during those days.

Keywords

GPS High-resolution NWM Mapping function Numerical weather model Precise point positioning Troposphere modeling VMF1 

Abbreviations

CMC

Canadian Meteorological Centre

ECMWF

European Centre for Medium-Range Weather Forecasts

GAPS

Global Navigation Satellite System Analysis and Positioning Software

GNSS

Global Navigation Satellite Systems

GPS

Global Positioning System

HRDPS

High Resolution Deterministic Prediction System

IERS

International Earth Rotation and Reference Systems Service

IGS

International GNSS Service

MF

Mapping function

NWM

Numerical Weather Model

PP

Point Positioning

PPP

Precise Point Positioning

SD

Slant delay

TUW

Technische Universität Wien

UNB

University of New Brunswick

VMF1

Vienna Mapping Functions 1

ZD

Zenith delay

Notes

Acknowledgements

The authors would like to thank: the Natural Resources Canada for the GPS data used in this study, belonging to the Canadian Active Control System; the Canadian Meteorological Centre, Environment and Climate Change Canada for providing the data necessary for the creation of the tropospheric parameters and specifically Dr. Edouard Sandrine for her valuable assistance retrieving the data; the Technische Universität Wien (TUW) for providing the VMF1 tropospheric parameters; last but not least, the editor and the two unknown reviewers for their constructive comments and helping to improve the manuscript.

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Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  • Thalia Nikolaidou
    • 1
    Email author
  • Felipe Nievinski
    • 2
  • Kyriakos Balidakis
    • 3
  • Harald Schuh
    • 3
    • 4
  • Marcelo Santos
    • 1
  1. 1.Department of Geodesy and Geomatics EngineeringUniversity of New BrunswickFrederictonCanada
  2. 2.Department of GeodesyFederal University of Rio Grande do SulPorto AlegreBrazil
  3. 3.GFZ German Research Centre for Geosciences, Space Geodetic TechniquesPotsdamGermany
  4. 4.Institute of Geodesy and Geoinformation ScienceTechnische Universität BerlinBerlinGermany

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