利用改进的能量守恒法,基于不同星间距离反演了120阶GRACE地球重力场.模拟结果表明:第一,基于相同的GRACE核心载荷精度指标反演长波(L≤20阶)地球重力场时,随着星间距离逐渐增大(110～330 km),累计大地水准面的精度依次提高.在20阶处,基于110 km星间距离反演精度为0.052 cm,基于220 km和330 km星间距离反演精度分别提高了1.156倍和1.209倍.第二,当反演中波(100≤L≤120阶)地球重力场时,在120阶处,基于110 km星间距离反演精度为13.052 cm,基于220 km和330 km星间距离反演精度分别降低了1.327倍和1.970倍.第三,星间距离设计为220±50 km可有效抑制由于星间距离选取不当而导致的长波和中波地球重力场精度的降低.%The GRACE Earth' s gravitational field complete up to degree and order 120 is recovered using the improved energy conservation principle and on the basis of different intersatellite ranges. The simulative results are as follows: Firstly, based on the same accuracy indexes of GRACE key payloads, while recovering the long-wavelength Earth's gravitational field (L≤20), with the increase of intersatellite ranges (110 ～ 330 kmn) little by little, cumulative geoid height errors will be improved gradually. At degree 20, the accuracy of cumulative geoid height is at the level of 0. 052 em based on 110 km intersatellite range, and accuracies are 1. 156 times and 1. 209 times improved as using 220 km and 330 km intersatellite ranges. Secondly, while recovering the middle-wavelength Earth's gravitational field (100 ≤L≤ 120), at degree 120, the accuracy of cumulative geoid height comes to 13. 052 cm based on 110 km intersatellite range, and accuracies are 1. 327 times and 1. 970 times degraded as using 220 km and 330 km intersatellite ranges. Lastly, intersatellite range designed as 220 ± 50 km can effectively suppress the decrease of the accuracies of long-wavelength and middle-wavelength Earth' s gravitational field induced by improper range.
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