多星混合资料的定轨∗

摘要

在空间目标光学观测资料定轨中常常会遇到多个目标的观测被标记为同一个目标的情况，由于包含了多个目标的数据，定轨过程无法收敛或者完全错误。从极大似然估计角度，采用EM (Expectation Maximum)方法提出一种将轨道改进和识别过程相互融合的处理方法，并在具体实现过程中给出一种稳健估计方法。数值模拟表明方法简便、有效、可行。采用站间差历元差的手段，对当前电离层变化值进行求解与预测，可以将电离层延时误差的变化控制在一定范围，满足频率传递的要求。%In the operational orbit determination with optical measurements of space ob jects, some observations of different ob jects are tagged as the same ob ject. For this kind of data, the orbit improvement according to the tag is failed because of the composition of multiple objects. A method is proposed from the view of maximum likelihood, and it combines the orbit improvement and identification by employing the EM (Expectation Maximum) method. In the implementation of this method, a robust estimation is also given. Corresponding numerical simulations show that the method is feasible, effective, and convenient.