Exploitation of the Potential of the SLR-tracked altimetry and GNSS satellites for determination of global geodetic parameters (PotS)

• Applicants: Dr.-Ing. Mathis Bloßfeld; Dr. Sergiy Rudenko
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 535929798

The main objective of this project is to investigate and exploit the potential of extending the commonly used four spherical satellite Satellite Laser Ranging (SLR) constellation by SLR-tracked non-spherical altimetry and Global Navigation Satellite System (GNSS) satellites to precisely and consistently determine global geodetic parameters. Such parameters are the coordinates of SLR stations in the global observation network, i.e., the Terrestrial Reference Frame (TRF), the origin and the scale of the TRF, Earth Rotation Parameters (ERP) and long-wavelength coefficients of the Earth’s time-variable gravity field. Taking into account two groups of non-spherical satellites, the altimetry and the GNSS satellites, this project goes beyond other studies that put their main focus on exploiting the full constellation of spherical (geodetic) satellites. Moreover, we will investigate the capability of different SLR-tracked satellite constellations (impact of specific non-spherical satellites), also in combination with Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS)-tracked satellites, to improve the above-mentioned global geodetic parameter groups in terms of accuracy, consistency and stability over time. Using a significantly increased number of observations by including observations to selected altimetry and GNSS satellites orbiting the Earth at various times, altitudes and inclinations will reduce the correlations between the estimated geodetic parameters and reduce errors of the estimated parameters. During the execution of this project, the following research questions will be answered: 1. Sensitivity: How sensitive are the global geodetic parameters to the SLR observations of each specific satellite (or groups of satellites)? 2. Precision: How precisely can the global geodetic parameters be determined and de-correlated from the analysis of SLR observations to the optimal multi-satellite (altimetry, GNSS, a combination of them, LAGEOS-1/2, and Etalon-1/2) solution compared to the conventional four-satellite setup? 3. Parameterization: What is the optimal orbit parameterization to achieve highest accuracy and stability of the global geodetic parameters? 4. Integration: What is the benefit of the integrated processing of DORIS and SLR observations in a multi-satellite solution comprising selected spherical SLR, altimetry and GNSS satellites for the determination of the global geodetic parameters? 5. Future: What is the impact of future SLR-tracked satellites on the global geodetic parameters? How should an extended space segment be designed? How can the SLR ground segment be extended to provide even more robust and accurate solutions?

• DFG Programme: Research Grants