Abstract:
Objectives Earth orientation parameters (EOP) is an important conversion parameter between the Earth body-fixed system and the celestial reference system. Due to complex data processing, EOP obtained by space geodesy technology has a delay from several days to two weeks. In order to guarantee the successful implementation of deep space exploration missions, it is necessary to study and analyze the influence of EOP prediction errors on orbit determination when real-time EOP accurate observations cannot be used.
Methods We analyze the prediction errors of Bulletin A issued by international earth rotation and reference systems service, and process the radio-tracking data from Mars express (MEX). The impact of EOP prediction errors on orbit determination is compared and analyzed by processing radio tracking data from MEX and the simulation data from asteroid 2016HO3 probe.
Results The orbiting errors of MEX generated by EOP predictions are mainly in the tangential and normal direction. The difference between universal time and coordinated universal time is defined as UT1-UTC, and the prediction errors of UT1-UTC are the main error terms on orbit determination of deep space spacecraft when using Doppler data. Based on the same UT1-UTC prediction error, the errors are on the order of a hundred meters for the asteroid probe and a thousand meters for the Mars orbiter.
Conclusions The errors of orbit determiantion have no absolute linear relationship with the EOP prediction time span, but are strongly correlated with the UT1-UTC prediction error. The error of orbit determination increases with the range rate between probe and ground for the same UT1-UTC prediction error.
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