VLBI technique for the orbit determination of Tianwen-1
SCIENTIA SINICA Physica, Mechanica & Astronomica(2022)
Since the launch of the Tianwen-1 probe on July 23, 2020, the orbit of this probe has been determined using very long baseline interferometry (VLBI) together with Doppler and ranging, and the Zhurong Mars rover has been located. More than 40 software and hardware sets have been developed, tested, and installed for VLBI to meet the Tianwen-1 high-precision orbit determination requirements. Until June 18, 2021, 198 VLBI observations have been performed. The measurement errors in VLBI time delay and time delay rate are