Objectives and Achievements of Dedicated Gravity Field Missions CHAMP, GRACE and GOCE

Determination of the Earth’s gravitational field with unprecedented accuracy is now a reality, thanks to the CHAMP, GRACE and GOCE missions. In this paper, dedicated gravity field missions CHAMP, GRACE and GOCE are briefly discussed and objectives and achievements of them are reviewed. After this review, recent satellite-only gravity fields from these missions are assessed in spectral domain. It is concluded that for the lower degrees, GRACE model is superior to that of CHAMP and GOCE. In the medium frequency range, the GRACE and GOCE models show similar behavior and finally in the high frequency part of the spectrum, the accuracy of the GOCE model is higher than that of the GRACE one. At the end, geoid undulations computed from these satellite-only gravity field models are compared with that of the EGM2008 model, and based on this comparison, some important characteristics of these missions are discussed.