Current deficiencies and potential for improvement in the realisation of consistently combined Earth Orientation Parameter time series

Accurate knowledge of the Earth’s orientation and rotation in space is essential for a broad variety of scientific and societal applications such as near-Earth and deep space navigation, global positioning and satellite orbit determination as well as monitoring geodynamics and climate change phenomena. Consequently, an essential basis for any of the above-mentioned applications is the accurate determination and prediction of Earth Orientation Parameters (EOP), which describe the instantaneous relation between reference frames fixed to the Earth and to inertial space at any epoch. High-precision EOP are determined by combining the observations of four different geodetic space techniques.

Due to different standards for the processing of the observations – most notably the parameterisation of the EOP in the observation-type-specific processing softwares – current EOP combination approaches lack consistency. Such inconsistencies represent a major limiting factor of today’s accuracy of determined EOP as well as of short-term EOP predictions, which are an essential prerequisite for any application in (near-)real time.

This study identifies current deficiencies that limit the consistency and achievable accuracy of combined EOP series. It provides recommendations on how to improve the parameterisation and processing standards of the technique-specific input, and it outlines strategies to achieve a more consistent and accurate EOP combination. The proposed processing strategies shall serve as a basis for improved EOP prediction algorithms in a later stage of the study.