Assessing the sensitivity of DORIS precise orbit determination to degraded Earth orientation information

Space-geodetic techniques rely on Earth orientation parameters (EOP) to relate satellite observations to terrestrial reference frames. While their importance for global consistency is well recognized, the sensitivity of satellite-based orbit determination to degraded Earth orientation information remains only partially quantified, particularly for techniques that depend on a combination of externally prescribed and internally estimated parameters.

In this contribution, we present a first assessment of the sensitivity of Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) geodetic products to degraded Earth orientation information. Using a standard DORIS processing configuration, in which UT1–UTC is prescribed from external products while polar motion can be estimated, we analyse how realistic perturbations applied to the Earth orientation time series propagate into observation residuals, orbital parameters, and empirical force modelling.

The study explores the extent to which DORIS solutions can accommodate degraded Earth orientation information through internal parameter adjustments, and examines the respective roles of different components of Earth rotation in this process.

This work provides initial insight into the robustness and limitations of DORIS-based geodetic products with respect to Earth orientation information, and contributes to a broader understanding of the dependence of satellite geodesy on high-quality geodetic products. As such, it provides technical elements relevant to the objectives of the United Nations Global Geodetic Centre of Excellence (UN-GGCE) in assessing the resilience and long-term sustainability of the global geodetic infrastructure.