Global Geodetic Observing System in Poland 2019–2022

This paper summarizes the contribution of Polish scientific units to the development of the Global Geodetic Observing System (GGOS) in recent years. We discuss the issues related to the integration of space geodetic techniques and co-location in space onboard Global Navigation Satellites Systems (GNSS) and Low Earth Orbiters (LEO), as well as perspectives introduced by the new European Space Agency’s (ESA) mission GENESIS. We summarize recent developments in terms of the European Galileo system and its contribution to satellite geodesy and general relativity, as well as ESA’s recent initiative – Moonlight to establish a satellite navigation and communication system for the Moon. Recent progress in troposphere delay modeling in Satellite Laser Ranging (SLR) allowed for better handling of systematic errors in SLR, such as range biases and tropospheric biases. We discuss enhanced tropospheric delay models for SLR based on numerical weather models with empirical corrections, which improve the consistency between space geodetic parameters derived using different techniques, such as SLR, GNSS, and Very Long Baseline Interferometry (VLBI). Finally, we review recent progress in the development of Polish GGOS scientific infrastructure in the framework of the European Plate Observing System project EPOS-PL¸

Optimum stochastic modeling for GNSS tropospheric delay estimation in real-time

In GNSS data processing, the station height, receiver clock and tropospheric delay (ZTD) are highly correlated to each other. Although the zenith hydrostatic delay of the troposphere can be provided with sufficient accuracy, zenith wet delay (ZWD) has to be estimated, which is usually done in a random walk process. Since ZWD temporal variation depends on the water vapor content in the atmosphere, it seems to be reasonable that ZWD constraints in GNSS processing should be geographically and/or time dependent. We propose to take benefit from numerical weather prediction models to define optimum random walk process noise. In the first approach, we used archived VMF1-G data to calculate a grid of yearly and monthly means of the difference of ZWD between two consecutive epochs divided by the root square of the time lapsed, which can be considered as a random walk process noise. Alternatively, we used the Global Forecast System model from National Centres for Environmental Prediction to calculate random walk process noise dynamically in real-time. We performed two representative experimental campaigns with 20 globally distributed International GNSS Service (IGS) stations and compared real-time ZTD estimates with the official ZTD product from the IGS. With both our approaches, we obtained an improvement of up to 10% in accuracy of the ZTD estimates compared to any uniformly fixed random walk process noise applied for all stations

Improved MSTID modelling and impact on precise GNSS processing

Peer ReviewedPreprin

Direct MSTID mitigation in precise GPS processing

This is the peer reviewed version of the following article: Hernandez, M., Wielgosz, P., Paziewski, J., Krypiak-Gregorczyk, A., Krukowska, M., Stepniak, K., Kaplon, J., Hadas, T., Sosnica, K., Bosy, J., Orús, R., Monte, E., Yang, H., Garcia-Rigo, A., Olivares-Pulido, G. Direct MSTID mitigation in precise GPS processing. "Radio science", Març 2017, vol. 52, núm. 3, p. 321-337, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/2016RS006159/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingIn this paper, the authors summarize a simple and efficient approach developed to mitigate the problem in precise GNSS positioning originated by the most frequent ionospheric wave signatures: the Medium Scale Travelling Ionospheric Disturbances (MSTIDs). The direct GNSS Ionospheric Interferometry technique (hereinafter dGII), presented in this paper, is applied for correcting MSTID effects on precise Real Time Kinematic (RTK) and tropospheric determination. It consists of the evolution of the former climatic Differential Delay Mitigation Model for MSTIDs (DMTID), for real-time conditions, using ionospheric data from a single permanent receiver only. The performance is demonstrated with networks of GNSS receivers in Poland, treated as users under real-time conditions, during two representative days in winter and summer seasons (days 353 and 168 of year 2013). In range domain, dGII typically reduces the ionospheric delay error up to 10-90% of the value when the MSTID mitigation model is not applied. The main dGII impact on precise positioning is that we can obtain reliable RTK position faster. In particular the ASR (ambiguity success rate) parameter increases, from 74% to 83%, with respect to the original uncorrected observations. The average of time to first fix is shortened from 30s to 13s. The improvement in troposphere estimaton, due to any potential impact of the MSTID mitigation model, was most difficult to demonstrate.Peer ReviewedPostprint (author's final draft

Reference frames and reference networks

The summary of research activities concerning reference frames and reference networks performed in Poland in a period of 2011-2014 is presented. It contains the results of research on implementation of IUGG2011 and IAU2012 resolutions on reference systems, implementation of the ETRS89 in Poland, operational work of permanent IGS/ EUREF stations in Poland, operational work of ILRS laser ranging station in Poland, active GNSS station networks in Poland, maintenance of vertical control in Poland, maintenance and modernization of gravity control, and maintenance of magnetic control in Poland. The bibliography of the related works is given in references

Reference frames and reference networks

The summary of research activities concerning reference frames and reference networks performed in Poland in a period of 2011-2014 is presented. It contains the results of research on implementation of IUGG2011 and IAU2012 resolutions on reference systems, implementation of the ETRS89 in Poland, operational work of permanent IGS/ EUREF stations in Poland, operational work of ILRS laser ranging station in Poland, active GNSS station networks in Poland, maintenance of vertical control in Poland, maintenance and modernization of gravity control, and maintenance of magnetic control in Poland. The bibliography of the related works is given in references