XY-2号卫星激光通信载荷PAT在轨测试

针对低轨小卫星星座的通信需求，设计了基于双棱镜和四象限雪崩光电二极管(QAPD)结构收发同轴的激光通信载荷，该方案是无信标光体制，具有体积小、轻量化和大视场的特点。文中针对双棱镜结构，给出了双棱镜输入输出光线的计算模型，在此基础上，提出了星间指向、捕获和跟踪的实现方式，并在XY-2号卫星上进行了在轨测试和验证，进行指向测试时，更新了指向偏移量，标定了QAPD跟踪点，并进行了双向建链测试。进行了15次双向建链测试表明，该激光通信载荷捕获时间小于20 s，捕获成功率达到100%，捕获后双星建链时间优于2 s，建链测试成功率达到了93%，建链后跟踪精度RMS值小于30 μrad。

XY-2 satellite laser communication equipment PAT test in orbit

According to the communication requirements of Leo satellite constellation, a laser communication equipment structure based on double Risley prisms and quadrant avalanche photodiode (QAPD) was designed. The scheme was beaconless optical system. It had the characteritics of small size, low weight and large field of view. In this paper, the calculation model of input and output light of double Risley prisms structure was given. On this basis, the interstellar of pointing, capturing and tracking was proposed, then in orbit test and verification were carried out on XY-2 satellite. The pointing offset was updated, based on pointing test, the QAPD tracking point was calibrated, and the two-way link up with the XY-2 satellite test was carried out. The bidirectional chain building test which was repeated 15 times showed that the acquisition time of the laser communication equipment was less than 20 s, and the acquisition success ratio was 100%. After the acquisition, the chain building time of the two satellites was better than 2 s and the linking success ratio reached 93%, and the RMS value of tracking accuracy was less than 30 μrad.