Contribution of simulated space VLBI to the Chang'E-1 orbit determination and EOPs estimation

Space very long baseline interferometry (SVLBI) is an extension of ground based VLBI to space, which has advantages, such as improving the precision and geometry structure of time delay observables with interconnecting multiple spatial coordinate systems directly. In this paper, a mathematical model of relativistic simulated SVLBI observables for estimating Chang'E-1 (CE-1) transfer orbit and Earth orientation Parameters (EOPs) is derived and discussed. A comparison of parameter estimation precision between ground ΔVLBI measurements and simulated SVLBI observables is carried out to verify the contribution of SVLBI. The optimal observation condition of CE-1 for SVLBI simulated observables is determined based on the analysis of parameter estimation results under CE-1 current observation condition. By using simulated SVLBI time delay observables under the optimal observation condition, the estimation precision of CE-1 orbit can achieve a level of 2 m. On the other side, the precision of some EOPs components can be improved when compared with their predicted values by fixed remaining components as known values. The method discussed in this paper provides a new attempt of deep space probe orbit determination and EOPs estimation.