Abstract:Simulation of onboard GPS data was completed using the simulation model of Bernese software.With the observation data obtained from simulation,The influence of different gravity field models(GEMT3、JGM3、EGM96、TEG4、EIGEN2 and EIGENGL04C)on the accuracy of orbit determination in loworbit satellites was analized by simplified dynamic orbit determination method.The results show that the simulation data is consistent with actual situation,which can meet the need of a variety of experimental analysis.The influences of different gravity field models and degree on the accuracy of orbit determination are different,and the best result with the models generated from CHAMP’s and GRACE’s gravity data were achieved.Compared to the other gravitational field models,the accuracy difference of orbit determination with the method is in centimeter level.