中文摘要：

针对月球探测中软着陆与采样返回段弹道计算问题,提出用数值逼近弹道确定方法。通过B样条对探测器状态进行建模,进而综合全弧段数据进行统计定轨的方法。由于样条法良好的数值逼近性能,使得该方法对探测器弹道异常复杂情况下的状态确定较为有效。对嫦娥三号探测器动力软着陆弧段进行了仿真与实测数据处理。分析了采样返回段的基本动力学与控制特征,为后续的嫦娥五号探测器的软着陆及其采样返回提供初步的可行弹道计算方法。在嫦娥三号探测器动力落月段实测数据处理中,通过评估,该段弹道确定精度优于100 m,其弹道末点与NASA的月球勘测轨道器（LRO）给出的结果差异优于50 m,证实了文章提出的软着陆弹道确定方法的有效性。

英文摘要：

A new method of trajectory determination for soft landing and sampling return for lunar probe by numerical approximation is presented. The method describes the probe＇s trajectory by B-spline and makes full use of all the tracking data to determine the trajectory. It is very suitable for fitting complicated trajectory for spline＇s special properties. The dynamics and control characteristics of the sampling return is analyzed, the preliminary feasible trajectory determination method for soft landing and sampling return of Chang＇ e - 5 is provided. By processing the simulation data and measured data of Chang＇ e - 3 lunar probe, it could be assumed that the accuracy of trajectory determination of soft landing is better than 100 meters in Chang＇ e -3 lunar probe data processing. It appears that the difference between the endpoint of the trajectory and the location got from the image processed by NASA＇s lunar reconnaissance orbiter（LRO） is less than 50m. It demonstrates the effectiveness of the method of soft landing trajectory determination provided by the paper is verified.