Combinations of earth orientation measurements: SPACE2018, COB2018, and POLE2018

Abstract

Reference series of Earth orientation parameters (EOPs) obtained by combining independent measurements of the Earth’s orientation are generated annually at the Jet Propulsion Laboratory (JPL) in support of tracking and navigation of interplanetary spacecraft. This report describes the generation of the most recent such combined Earth orientation series: SPACE2018, COMB2018, and POLE2018. Since the procedures used to generate these most recent series are similar to those used to generate previous such combinations, only a brief description of their generation is given here. Further details regarding the approach used at JPL to annually combine independent measurements of the Earth’s orientation can be found in Gross (1996, 2000) and Gross et al. (1998).