针对星上激光通信终端二维转台的精确控制，设计了实时测量转台旋转角度的专用型光电角度编码器。根据星载激光通信终端所需测角系统的设计指标，分别对光电角度编码器的码盘、指示光栅及光电信号的提取方法进行了设计和选择。其中，格林二进制绝对式编码结合高质量的电子学细分，实现了编码器24位的绝对角度测量; 四象限矩阵编码方式有效地减小了码盘的径向尺寸; 分体读数头式指示光栅较整周玻璃盘大幅度压缩了体积和重量。在室温条件下对安装在星载激光通信终端上的光电角度编码器进行了测角精度检测。结果表明: 该测角系统的角度测量精度约为0.7″(优于1.0″)。激光通信终端设备的在轨稳定运行及捕获、跟踪和通信功能的正常发挥，进一步验证了所设计的光电角度编码器测角精度高、抗辐射能力强、工作可靠性高，满足星载激光通信终端设备的应用要求。

To control precisely the 2D rotation stable of a laser communication terminal unit on the satellite platform, a special optical angle encoder was designed to measure the rotary angle of the 2D rotation stable to realize the close control of the terminal unit. The grating disk, index grating and a signal pick-up method were designed and chosen respectively on the basis of design requirements of angle measurement device in the laser communication terminal. An absolute type binary coding was combined with a high quality electronics dividing to implement 24 bit absolute angle measurement of the encoder, and a four quadrant matrix encoding was used to effectively reduce the radial size of encoder. Moreover, the parted reading head type indicating gratings were employed in the encoder to allow its volume and weight to be smaller and lighter than that of the whole glass grating disk. The angle measurement precision of an optical angle encoder mounted on the satellite borne laser communication terminal unit was tested and analyzed after finely manufacturing, assembling and adjusting at a indoor temperature. The results show that precision of the designed encoder is about 0.7″(is superior to 1.0″). The laser communication terminal unit on the satellite platform operates normally in orbit and completes capturing, tracking and communication of the signals, which verifies that the designed encoder is characterized by high precision, high resistance to radiation and high working reliability.