Assessing the performance of multi-GNSS precise point positioning technique on the geoid model validation

Abstract

This study aims to investigate the comparative performance of PPP technique in evaluating the precision of three distinct geoid models and to quantify the contribution of GLONASS constellation to GPS as well as the effect of observation length. We use recently and concurrently measured GNSS and levelling data crossing rough topography with steep geoid slope in Türkiye. The RMSE statistics about the mean of the geometric minus gravimetric geoid heights reveal that at least 4-hours of static data should be collected regardless of the constellation. We find out encouraging results with 8-hours of GPS + GLONASS solutions having RSME values of 3.0, 5.0 and 21.5 cm in validating national, globally combined and satellite-only geoid models, respectively. The multi-GNSS PPP processing with a relatively long observation period yields comparable results to relative positioning though the latter still performs slightly better.

Keywords:

• Precise point positioning
• Baseline positioning
• Multi-GNSS
• Validation of geoid precision
• GNSS-levelling
• Türkiye

Acknowledgements

The work presented here is conducted by a working group formed under the cooperation protocol signed between the General Directorate of Mapping (GDM) and Hacettepe University in 2020. We would like to thank the GDM to provide us with the data.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Please contact the General Directorate of Mapping at [email protected] to access the data.

Additional information

Funding

This research received no external funding.

Notes on contributors

Mehmet Simav

Mehmet Simav is currently a senior geomatic engineer and associate professor of geodesy leading the Geophysics & Levelling Section of General Directorate of Mapping, the national mapping agency of Türkiye. His research interests include the static and mobile gravimetry, Earth’s gravity field, inertial & satellite navigations, sea level measurements and analysis, and vertical coordinate reference system.

Berkay Bahadur

Berkay Bahadur received his Ph.D. degree from Hacettepe University in 2021. Currently, he is a research assistant at Hacettepe University, Geomatics Engineering Department. His research interests include Precise Point Positioning, multi-GNSS integration, real-time positioning applications, real-time tropospheric delay retrieval, robust statistics methods in GNSS and precise positioning with smartphones.

Hasan Yıldız

Hasan Yıldız is a senior geomatic engineer and associate professor of geodesy, and currently the director of Higher Technical School of Surveying in General Directorate of Mapping. His research interests include sea level change, geoid determination, satellite altimetry, airborne and satellite gravity field modelling.

Ayhan Cingöz

Ayhan Cingöz is a geodetic engineer, MSc at General Directorate of Mapping. His research interests include installation and maintaining of satellite based geodetic control networks, real-time kinematic positioning applications and GNSS analysis.

Metin Nohutcu

Metin Nohutcu received his Ph.D. degree from Middle East Technical University (METU) in 2009. Currently, he is an associate professor at Hacettepe University, Geomatics Engineering Department. His research interests include ionosphere modelling with GNSS data, determination of ionospheric effective height and precise GNSS positioning.

Erdinç Sezen

Erdinç Sezen is a geomatic engineer at General Directorate of Mapping. He received his Ph.D. degree from Yıldız Technical University in 2016. His research interests include height systems, levelling network, geoid determination and tide gauge operation.