GPS Solutions

, Volume 21, Issue 4, pp 1479–1489 | Cite as

Using external tropospheric corrections to improve GNSS positioning of hot-air balloon

  • Pavel VaclavovicEmail author
  • Jan Dousa
  • Michal Elias
  • Jakub Kostelecky
Original Article


High accurate global navigation satellite systems (GNSS) require to correct a signal delay caused by the troposphere. The delay can be estimated along with other unknowns or introduced from external models. We assess the impact of the recently developed augmentation tropospheric model on real-time kinematic precise point positioning (PPP). The model is based on numerical weather forecast and thus reflects the actual state of weather conditions. Using the G-Nut/Geb software, we processed GNSS and meteorological data collected during the experiment using a hot-air balloon flying up to an altitude of 2000 m. We studied the impacts of random walk noise setting of zenith total delay (ZTD) on estimated parameters and the mutual correlations, the use of external tropospheric corrections, the use of data from a single or dual GNSS constellation and the use of Kalman filter and backward smoothing processing methods. We observed a significant negative correlation of the estimated rover height and ZTD which depends on constraining ZTD estimates. Such correlation caused a degraded performance of both parameters when estimated simultaneously, in particular for a single GNSS constellation. The impact of ZTD constraining reached up to 50-cm differences in the rover height. Introducing external tropospheric corrections improved the PPP solution regarding: (1) shortened convergence, (2) better overall robustness, particularly, in case of degraded satellite geometry, (3) less adjusted parameters with lower correlations. The numerical weather model-driven PPP resulted in 9–12- and 5–6-cm uncertainties in the rover altitude using the Kalman filter and the backward smoothing, respectively. Compared to standard PPP, it indicates better performance by a factor of 1–2 depending on the availability of GNSS constellations, the troposphere constraining and the processing strategy.


GNSS Tropospheric corrections Zenith total delay Numerical weather forecast Precise point positioning Kinematic positioning 



The experimental data collection, processing and tropospheric model enhancement have been supported by the ESA project DARTMA (EGEP-ID-89 06). The initial tropospheric model development has been supported by the ESA project Trop4LAS. We acknowledge the provision of data from operational weather forecasts run by the Institute of Computer Science of the Academy of Sciences, Czech Republic, within the DARTMA project.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Pavel Vaclavovic
    • 1
    Email author
  • Jan Dousa
    • 1
  • Michal Elias
    • 1
  • Jakub Kostelecky
    • 1
  1. 1.NTIS – New Technologies for the Information SocietyGeodetic Observatory Pecny, RIGTCZdibyCzech Republic

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