卫星重力场测量已成为最有效的全球重力场测量手段.本文结合典型的重力卫星和重力卫星研究计划,分析了卫星重力测量的三种原理,并基于各阶位系数的相对权重讨论了各种原理的应用优势.分析可知,卫星受摄轨道适用于恢复长波重力场,低轨星间距离变化率适用于恢复中长波重力场,重力梯度适用于恢复中短波重力场.针对中长波高精度重力场测量的需要,设计了综合获取低轨星间距离变化率与受摄轨道的重力卫星方案,该方案由两组内编队组成星星跟踪复合编队,轨道高度为250km,星间距离为50~100km.
Satellite gravity measurement has been the most efficient method for global gravity model recovery and geoid height determination. With a brief introduction of the representative satellite gravity missions, including CHAMP (A Challenging Minisatellite Payload for Geo-science and Application), GRACE (Gravity Recovery And Climate Experiment), GOCE (Gravity field and steady-state Ocean Circulation Explorer), Inner Formation, GRACE Follow-on and NGGM (Next-Generation Gravimetry Mission), their measuring principles were analyzed and classified into three kinds, which were gravity field recovery with the satellite ephemeris, gravity field recovery with the inter-satellite range-rate and gravity field recovery with gravity gradient measurements. Base on the definition of relative weight for the gravitational potential coefficients of different degrees, application advantages of each measuring principle were analyzed primarily. It is found that there are different sensitive bands for the three measuring principles and they are long wave gravity field recovery, medium-long wave gravity field recovery and medium-short wave gravity field recovery, respectively. The highest degree which could be recovered by a mission can be estimated through the analysis. For example, it is estimated that the CHAMP mission can improve the global gravity model to degree 60 - 100, which accords with the known degree 70 in deed. There are also good consistencies in the recovery degrees for GRACE and GOCE missions. Meanwhile, it can be concluded that multi- measuring principles must be used to improve the global gravity field model in whole bands. With the requirement of high accuracy medium and long wave global gravity model, the satellite gravity measurement system using two Inner Formations fling in the same 250 km altitude orbit with a inter-satellite distance of 50- 100 km is proposed. This system can obtain the ephemeris and range-rate measurements simultaneity.