The overall project goal of NextGNSS4GGOS is to assess the benefits of next-generation Global Navigation Satellite Systems (NextGNSS) constellations beyond current GPS, GLONASS, Galileo, or Beidou for the three key geodetic objectives:

1. the generation of the global terrestrial reference frame (TRF),
2. the monitoring of Earth’s orientation in space and its rotation described by Earth Orientation Parameters (EOP), and
3. the monitoring of the shape and variations of Earth’s physical figure, all of them meeting the requirements defined by the Global Geodetic Observing System (GGOS).

Comprehensive and most realistic simulations are carried out using Section 1.2 inhouse developed software EPOS (Earth Parameter and Orbit System) in order to analyze the potential of NextGNSS constellations equipped with new observation types (inter-satellite ranges, highly precise optical clocks, non-gravitational accelerations, attitude data, laser-retroreflectors for Satellite Laser Ranging (SLR), or transmitters for Very Long Baseline Interferometry (VLBI)) for improved TRF, EOP and gravity field determination. Therefore, the central research question of this proposal is addressed as:

Can envisaged NextGNSS-based TRFs, EOPs, and gravity field models meet the GGOS requirements of 1 mm accuracy and 1 mm per decade long-term stability?

Project Partners:

• GFZ Section 1.1
• Project PI is Prof. Dr. Susanne Glaser, (formerly Section 1.1, now University of Bonn)

Project Duration:

• December 2021 – August 2025

Funding:

• German Research Foundation (Deutsche Forschungsgemeinschaft, DFG), GL 1028/1-1 (see: gepris.dfg.de/gepris/projekt/451901242)

Project related Publications:

• Schreiner, P. A., König, R., Neumayer, K., Reinhold, A. (2023): On precise orbit determination based on DORIS, GPS and SLR using Sentinel-3A/B and -6A and subsequent reference frame determination based on DORIS-only. - Advances in Space Research, 72, 1, 47-64.
  https://doi.org/10.1016/j.asr.2023.04.002
• Neumayer, K. H., Schreiner, P. A., König, R., Dahle, C., Glaser, S., Mammadaliyev, N., Flechtner, F. (2024 online): EPOS-OC, a Universal Software Tool for Satellite Geodesy at GFZ. - In: (International Association of Geodesy Symposia), Berlin, Heidelberg : Springer.
  https://doi.org/10.1007/1345_2024_260
• Raut, S., Glaser, S., Mammadaliyev, N., Schreiner, P. A., Neumayer, K., Schuh, H. (2023 online): Assessing the Potential of VLBI Transmitters on Next Generation GNSS Satellites for Geodetic Products. - In: International Association of Geodesy Symposia, Berlin, Heidelberg : Springer.
  https://doi.org/10.1007/1345_2023_217

Section 1.2 employee Patrick Schreiner will complete his Ph.D. on this topic at TU Berlin in mid of 2025.