Trajectory Estimation Analysis and Low Degree Gravity Field Recovery Based on Juno Tracking Data

  Objectives  With the development of deep-space technology of China, the Jupiter exploration program has been added into the schedule. The precise orbit determination (POD) and gravity field recovery play an important role in Jupiter exploration.

  Methods  This paper focuses on the precise orbit determination of Juno and low degree gravity field recovery of Jupiter. Firstly, the coordinate system and dynamics model of the Jupiter probe are given, and the Juno precision ephemeris of jet propulsion laboratory (JPL) is used for verification.Then, the deep-space Doppler measurement model is presented and the trajectory of Juno is calculated by using the tracking data.

  Results  The dynamical fitting position difference is on the order of 10 m, and the velocity difference is less than 6 mm/s. The difference with the reference orbit given by JPL is better than 1 kilometer.

  Conclusions  The simulation data is used to verify the reliability of gravity field solution, and the measured data near 4 perijove points of the Juno is used to calculate the gravity field coefficients of Jupiter, obtaining the gravity fieldzonal coefficients up to 8 degrees.