“嫦娥4号”中继星使命轨道段定轨计算与分析

Orbit Determination and Analysis of Chang’E-4 Relay Satellite on Mission Orbit

“嫦娥4号”中继星是“嫦娥4号”探测器实现月球背面着陆与巡视的关键,目前正稳定运行在地-月L2点使命轨道上,该使命轨道为平均周期约14天的南族Halo轨道。因任务的需要,中继星本体系+Z轴需调整指向,处于正对太阳和非正对太阳两种状态。太阳光压在中继星+Z轴对日的情况下会加速卫星的角动量累积,增加卫星卸载喷气频次。基于中继星使命轨道段测控支持条件,采用重叠弧段法对两种状态下的中继星定轨精度进行分析与评估。结果表明,在中继星+Z轴非对日运行状态下,重叠弧段位置误差为1.6km,速度误差为8mm/s;在中继星+Z轴对日运行状态下,重叠弧段位置误差为0.6km,速度误差为3mm/s,这对中继星的长期运行具有重要参考价值。

Chang’E-4 relay satellite that flying on the mission orbit at the Earth-Moon L2 is the key for the probe to complete the landing and inspection on the farside of the moon,with the mission orbit of the southern clan Halo orbit with an average period of 14 days. Due to mission requirements, the + Z axis of the relay satellite will be in two states: orientation to the sun and orientation to the moon or the earth. In the non-directional orientation of the sun,the solar pressure will accelerate the angular momentum accumulation of satellites and increase the frequency of satellite jets. In this paper,under the existing TT&C conditions, the orbit determination accuracy of satellites in the two states is analyzed and evaluated by using overlapping arc method. The results show that the position error of overlapping arcs is 1.6 km and the velocity error is 8 mm/s for the relay satellite when the + Z axis is not pointing to the sun,while the position error of overlapping arcs is 0.6 km and the velocity error is 3 mm/s for the relay star when the + Z axis is pointing to the sun. This has important reference value for the long term operation of relay satellites.