Small Body and planets Precise Orbit Determination Toolkit (SPOT) and Its Application

The orbiting and positioning of probes in deep-space exploration missions cannot be separated from the support of a software platform for precise orbit determination. The development of a software platform is essential in engineering and scientific applications. Thus, the Wuhan University planetary geodesy group has independently developed a software platform, called Small Body and planets Precise Orbit Determination Toolkit (SPOT), in response to the demand for spacecraft precise orbit determination. Moreover, aligned with the goal of supporting China’s first asteroid exploration mission, this initiative will significantly enhance the country’s scientific contributions in the field of radio science. This paper briefly introduces the design concept, core structure, and main functions of SPOT, and subsequently focuses on some simulation experiments and real tracking data analysis based on SPOT. The functionality and self-consistency of the SPOT were verified through simulation experiments, and construction of some new measurement models and inversions of small body gravity fields. The reliability of the software platform was further verified from the processing of radio tracking data and landmark data from the Rosetta mission, as well as from the Neptunian gravity estimated from the motion of Triton based on astrometric observations. The computational efficiency and accuracy of SPOT have reached international equivalent level.