Expected accuracy of the global gravity field for next GRACE satellite gravity mission

For the technology of low-low satellite to satellite tracking, this paper focuses on a method which combines the precise orbit data with range data or range rate data to recover the global gravity field. It not only can calibrate the initial position error of the two satellites, but also make good use of the low frequency gravity information from the mission. Several simulation scenarios are discussed in this paper. The results are as follows. (1) If the precision of range rate measurement is improved by a factor of ten, the accuracy of global gravity field will be 10.6 times better; (2) The accuracy of the global gravity field will be higher than that of GRACE by a factor of about 121 if we use the following accuracy indexes; the accuracy of range rate, altitude, acceleration, orbit position and the distance between the two satellites is 1.0 x 10(-8) m.s(-1), 300 km, 3.0 x 10(-10) m.s(-2) 0.03 m, and 100 km, respectively. Therefore, we recommend the payloads mentioned above for Chinese future satellite gravity mission.