由于当前GRACE(Gravity Recovery and Climate Experiment)串行式编队存在"南北向条带误差"等缺陷,因此本文基于星间速度插值法开展了利用下一代三向车轮双星编队ACR(Along-Cross-Radial)-Cartwheel提高地球重力场空间分辨率的可行性研究论证.第一,采用GRACE卫星轨道参数和关键载荷精度,利用三向车轮双星编队ACR-Cartwheel-A/B反演了120阶地球重力场.结果表明:基于ACR-Cartwheel-A/B双星编队反演地球重力场的模拟精度较德国波茨坦地学研究中心(GFZ)公布的EIGEN-GRACE02S地球重力场模型的实测精度平均提高2.6倍,从而检验了基于下一代三向车轮双星编队ACR-Cartwheel-A/B反演地球重力场精度优于当前GRACE串行式双星编队的可行性.第二,通过星间速度插值法,采用卫星轨道参数(初始轨道高度350km、平均星间距离100km、初始轨道倾角89°、初始轨道离心率0.0046)、卫星关键载荷精度指标(星间速度10-7 m·s-1、轨道位置10-3 m、轨道速度10-6 m·s-1、非保守力10-11 m·s-2)、观测时间30天和采样间隔10s,基于经向车轮双星编队Lo-AR(Longitudinal-Along-Radial)-Cartwheel-A/B、纬向车轮双星编队La-AR(Latitudinal-Along-Radial)-Cartwheel-A/B和三向车轮双星编队ACR-Cartwheel-A/B,分别反演了120阶地球重力场;在120阶处,累计大地水准面精度分别为5.115×10-4 m、4.923×10-4 m和3.488×10-4 m.结果表明:(1)由于La-AR-Cartwheel-A/B编队的轨道稳定性优于Lo-AR-Cartwheel-A/B编队,因此基于La-AR-Cartwheel-A/B编队反演重力场精度高于Lo-AR-CartwheelA/B编队;(2)由于ACR-Cartwheel-A/B编队可以同时获得轨向、垂向和径向的重力场信息,卫星观测数据具有各向同性优点,因此ACR-Cartwheel-A/B编队是建立下一代高精度和高空间分辨地球重力场模型的优化选择.
Because the design defects(e.g.,the orbital altitude could not be substantially decreased,the measurement accuracy of space-borne instrumentations is unable to be sufficiently improved,and the isotropic gravity information is incapable of being simultaneously acquired,etc.)of the present twin Gravity Recovery and Climate Experiment(GRACE)satellites have resulted in poor spatial resolution of the Earth′s gravitational field,this study aims to carry out the feasibility demonstrations regarding the next-generation ACR(Along-Cross-Radial)-Cartwheel twin-satellite formation for improving the spatial resolution of the Earth′s gravitational field by the intersatellite range-rate interpolation method.The research on improving the accuracy of the Earth′s gravitational field by the Radial-Cartwheel and Inclined-Cartwheel twin-satellite formation has been developed using the short-arc integral approach.The disadvantage of the short-arc integral approach is that the accuracy of the Earth′s long-wavelength gravitational field is apt to be decreased owing to a shorter orbital arc of about 30 minutes.The different methods of satellite gravity recovery have different sensitivities to the signal spectrum of gravity field.Unlike previous recovery methods,we perform the exploratory investigations on optimizing spatial resolution by the future ACR-Cartwheel-A/B twin-satellites formation based on the six-point intersatellite range-rate interpolation method.Firstly,the Earth′s gravitational field from ACR-Cartwheel-A/B complete up to degree and order 120 is precisely recovered using the satellite orbital parameters and the measurement precision of key payloads from the twin GRACE satellites.The research results show that the accuracy of the Earth′s gravitational field determination from the next-generation ACR-Cartwheel twin-satellite formation is averagely improved by 2.6 times than that from the EIGENGRACE02 S model released by the German GeoForschungsZentrum Potsdam(GFZ),which sufficiently verifies that