Firstly,the Earth's gravitational field from the past Challenging Minisatellite Payload(CHAMP) mission is determined using the energy conservation principle,the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment(GRACE) and future GRACE Follow-On missions is established based on the semi-analytical method,and the Earth's gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer(GOCE) mission is recovered by the space-time-wise approach.Secondly,the cumulative geoid height errors are 1.727 × 10^(-1) m,1.839 × 10 ^(-1) m and 9.025 × 10^(-2) m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP,GRACE and GOCE,which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03 S,EIGEN-GRACE02 S and GO_CONS_GCF_2_DIR_R1.The cumulative geoid height error is 6.847 × 10^(-2) m at degree 250 from the future GRACE Follow-On mission.Finally,the complementarity among the four-stage satellite gravity missions including CHAMP,GRACE,GOCE and GRACE Follow-On is demonstrated contrastively.
In this paper,the technological progress on Chinese gravity exploration satellites is presented.Novel features such as ultra-stable structure,high accurate thermal control,drag-free and attitude control,micro-thrusters,aerodynamic configuration,the ability to perform micro-vibration analyses,microwave ranging system and mass center trimmer are described.
