Determination of Precise Orbit Using Onboard GPS Data for Gravity Modeling Oriented Satellites

Both kinematic and reduced dynamic orbit determination for CHAMP and GRACE satellites are studied.Data cleaning is a crucial step for kinematic POD.In the process,a reduced-dynamic orbit is firstly determined to detect outliers and cycle slips in the data.The accuracy of the precise orbit is assessed by comparing them with DEOS,JPL and TUM reduced dynamic orbits as well as with SLR data.Furthermore,gravity field models recovered from the computed kinematic orbits are compared with those derived from TUM kinematic orbits.The comparison results confirm a high quality of our computed kinematic orbits.