空间引力波探测中为实现引力波信号科学测量, 卫星发射到预定轨道后需首先完成百万公里级激光链路的构建。同时为保证引力波信号不会被激光指向噪声淹没, 激光指向稳定性需达到nrad/Hz量级。为此需设计一套复杂而精密的激光指向调控方案。本文以太极计划为背景, 详细阐述了可采用的指向调控方案。拟将整个过程将分为两个阶段, 首先进行激光捕获过程, 在该过程中, 使用星敏感器(STR)与电荷耦合器件(CCD)作为辅助捕获探测器, 将激光指向不确定区域控制到μrad量级。之后进行激光精密指向过程, 利用差分波前敏感测角(DWS)技术对激光指向稳定性进行控制。根据太极计划要求, 对各阶段捕获探测器提出了视场及精度要求, 并论述了采用DWS技术实现精密指向的可行性。相关结论可为未来的验证实验奠定理论基础, 对太极计划指向系统构建提供参考。

To realize scientific measurement of gravitational waves in the space gravitational wave detection, after launching into a predetermined orbit, the satellites must first construct a 100-km laser link. Furthermore, to prevent the gravitational wave signal from being flooded by laser pointing noise, the laser pointing stability must reach a magnitude of nrad/Hz. Therefore, a sophisticated laser pointing scheme has to be adopted. In this paper, based on the Taiji program, we will discuss the design of such a scheme, which can be divided into two phases. Laser acquisition will be the first process. A star sensor(STR) and a charge coupled device(CCD) will be used as auxiliary capture detectors to decrease the laser pointing uncertainty region to sub-μrad levels. After that will be the laser fine pointing process, which uses differential wavefront sensitive(DWS) technology to accurately control pointing direction. The requirements of the acquisition sensors will be proposed based on the Taiji program while the feasibility of the DWS technique in the laser fine pointing phase will be discussed. The conclusions of this paper can be regarded as the basis and principle of related experiments and will give a reference for system construction in the laser pointing scheme of the Taiji program.