CE-5器间分离的同波束干涉测量的准实时监测法

Quasi real-time monitoring of CE-5 inter-device separation based on same-beam interferometry

“嫦娥5号”探测器的组成包括轨道器、返回器、着陆器和上升器。在环月阶段,两个组合体(轨道器/返回器组合体和着陆器/上升器组合体)之间的分离实时监测,是飞行控制的关键检测段。本文提出利用甚长基线干涉测量(VLBI)测轨技术实现绕月探测器器间分离实时监测。特别是在器间分离前后,本文方法能够利用探测器器间两路下行信号进行同波束干涉测量(SBI),差分时延测量能够提高器间相对距离的解算精度。单基线试验分析表明,本文方法基于实测数据的“嫦娥3号”着陆器两天线的相对距离解算精度优于0.3m,平均相对距离误差约为0.15m,基于“嫦娥5号”仿真数据的双阈值判定对器间分离监测的响应时延优于30s。

The lunar spacecraft Chang’E-5 includes the orbiter, the returner, the lander and the riser. During the round-moon flight phase, the real-time monitoring of separation between two combinations, the orbiter/returner assembly and the lander/riser assembly, is the key detection section of flight control. It is proposed that a nearly real-time separation monitoring by using very long baseline interferometry (VLBI) technology. Particularly, during the separation process, the state-of-art measuring technique of same-beam interferometry (SBI) can be obtained from the downlink signals transmitted from the different antennas of the two assemblies, and the resulting relative phase delay can improve the relative distance resolution. The Chang’E-3 static test shows that the relative distance between the two antennas of its lander is solved with the accuracy of <0.3 m with the SBI measurements on a single baseline and the average error is about 0.15 m . The simulated Chang’E-5 separation shows that the separation response time based on SBI measurements is determined with double thresholds with a delay of no more than 30 s.