应用天文研究组知识库

将4×4多像素光子计数器(MPPC)阵列作为回波探测器,利用云南天文台升级后的1.2m望远镜分光路卫星激光测距(SLR)系统,开展了地面漫反射靶和AJISAI卫星的SLR试验。地面靶目标是60cm×40cm的Al塑板,光程约为45m,用示波器采集单通道输出信号与16通道合并输出信号,合并输出信号幅值明显高于单通道输出信号,表明不止一个通道有响应;用事件计时器记录主波、回波时刻并进行距离解算,其RMS约为21.7cm,与激光脉冲宽度、漫反射目标的形状效应引起的测距误差相当。实验结果表明,阵列型探测器较单元型有一定优势,实验中采用的MPPC阵列探测器进行性能升级后可用于SLR。

Using a 4 × 4 multi pixel photon counter （MPPC） array as a echo detector, an upgraded satel- lite laser ranging system with a 1.2 m aperture telescope is designed,and the experiments for diffuse re- flection target and AJISAI satellite are carried out at Yunnan Observatories. Aluminum foil at an approx- imate distance of 45 m with an area of 60 cm× 40 cm acts as a diffuse reflection target. Both single-chan- nel output signal and combined 16-channel output signal are captured by an oscilloscope, which show that the combined output signal has a much higher amplitude than that of single-channel output signal,indica- ting that more than one channel of the array can respond for photons. Event timer records both the start- ing timestamp and echo timestamp,from which the distance can be obtained. Ranging results for diffuse reflection target shows that the root mean square （RMS） is about 21.7 cm, which matches the laser pulse width and the range error caused by reflection target＇s form effect. Experimental performance shows that the array-type MPPC detector has certain advantages over a single-unit detector. The MPPC array detector used in experiments needs further improvement for better performance in future .ql .R