卫星精密定轨与重力场建模的同解法

现代卫星跟踪卫星重力测量技术显著改善了地球重力场模型的中长波段信号,并拓展了重力场模型在相关科学研究中的应用.同解法作为卫星重力观测数据的主要处理手段之一,国内一直没有实质突破.本文从基本模型和关键技术的分析出发,剖析了同解法的特点,特别是在建立同解法与几何法(运动学)定轨、一般动力学方法关系的基础上,给出了一种同解法的实现路线.在已有的精细数据预处理和并行计算研究基础上,结合GRACE卫星的实测飞行数据,在国内首次获得了真实卫星任务数据条件下的同解法结果,并进行了动力法轨道的外部质量检核、卫星非保守力分析、重力场模型的GPS水准检验等.利用卫星激光测距数据检验,卫星精密轨道的径向精度优于2cm,同时建立了质量可靠的卫星重力场模型,充分展示了同解法的优点.数值结果及其分析表明,本文所提的同解法实施方案合理可行,已经掌握了实现同解法的关键技术,获得了从仿真研究到实际飞行数据处理的新进展.最后,本文对同解法今后的发展思路,以及如何进一步挖掘同解法的潜力,提出了见解和今后的工作方向.

Simultaneous solution for precise satellite orbit and earth gravity model

The modern satellite gravimetry missions have improved the mid-term and long wavelength parts of the earth gravity model significantly, and extended its usage in the scientific research in the relating subjects. The simultaneous solution method, which is one of the major methods used in the data processing for satellite gravimetry, is still under developing in China. Based on the basic model and some key technologies, especially on its relation with the kinematic orbit determination and the general dynamic method, the strategy on how to implement the simultaneous solution method is given in detail. And the real data from GRACE mission is analyzed with this method with the help of some work already done by our group. Some evaluations, including the external checks on the accuracy of the orbit, the analysis on the non-conservative forces and the earth gravity model validation by the GPS/Leveling benchmarks are conducted. The numerical results show that the strategy on the realization of the simultaneous solution method is valid, and reveal its advantages distinctly. It is assumed that the key technologies of the simultaneous solution method have been solved, and an advance from the simulation stage to the real data analyzing is achieved. Finally, some prospects and future work are discussed to exert the potential ability of this method.