Genesis contribution to SLR-based geodetic parameters

Abstract Satellite laser ranging (SLR) is one of the space geodetic techniques used to realize the International Terrestrial Reference Frame (ITRF). SLR contributes considerably to geocenter determination and scale realization. The currently being prepared European Space Agency’s (ESA) mission, Genesis, will co-locate all four space geodetic techniques onboard one satellite. However, Genesis’s contribution and impact of single techniques, e.g., SLR, on the geodetic products, i.e., geocenter coordinates, Earth rotation parameters (ERP), or coefficients of Earth’s gravity field, is still unveiled. Another vital question is the impact of Genesis orbit parameters, especially semi-major axis and inclination, on the quality of geodetic parameters. The orbit parameters will substantially affect the number of possible observations collected by SLR stations but also favor different geodetic parameters by decreasing or increasing their estimation error. We study two approaches to processing Genesis data—one with estimating Genesis orbits based on SLR observations and one with fixing the orbital parameters to GNSS-based values. As we do not analyze Genesis as a single satellite but in combination with LAGEOS and LARES, we conclude that the ESA proposition of orbit will ensure good observability. The orbit proposal for Genesis with the inclination angle of 95° and the height of 6000 km might help to reduce the errors of the Z component of the geocenter motion below 1 mm, especially with the GNSS contribution, which is the aim of the Global Geodetic Observing System for the stability of the ITRF realization.