Chang'E-1 precision orbit determination and lunar gravity field solution

Abstract

In this paper we presented results assessing the role of space VLBI tracking data for precision orbit determination (POD) for Chang'E-1 and corresponding lunar gravity field solution based on tracking data of Chang'E-1, China's first lunar exploration mission. The POD of the lunar orbit segment of Chang'E-1 was performed using S-band two-way Range and Range Rate (R&RR) data, together with VLBI delay and delay rate data. The role of VLBI data in the POD of Chang'E-1 had been analyzed, and the orbit accuracy was given with different orbit solution strategies. We concluded that the VLBI tracking data contributed significantly to the Chang'E-1 POD. Based on POD of Chang'E-1, the lunar gravity field solution CEGM based on six months tracking data was presented, the accuracy of the model was assessed by gravity field power spectrum and admittance/coherence between gravity and topography, the result showed that CEGM had significant improvement than a prior model GLGM-2.