基于近红外小功率卫星激光测距研究

Satellite laser ranging research based on near-infrared low-power laser

为分析天琴计划激光测距台站卫星激光测距探测能力,设置单脉冲能量(平均功率)分别为0.15 mJ(0.015 W),0.4 mJ(0.04 W)和4 mJ(0.4 W)对同步轨道卫星qzs2、compassi3和compassi5分别于夜晚和白天进行激光测距实验。理论方面,分析了白天天光背景噪声强度,并结合雷达方程计算了不同平均功率条件下卫星激光测距的有效回波率,重点分析了平均功率对卫星激光测距探测能力的影响。实验方面,固定望远镜俯仰角(E=50°),旋转望远镜测量不同指向时的天光背景噪声强度。采用探测效率为60%(@1064 nm)的超导探测器阵列,并结合空间滤波、时间滤波和光谱滤波的方法抑制背景噪声,开展了小功率白天卫星激光测距。分析得到,白天对同步卫星激光测距的最小功率为0.04 W,夜晚对同步卫星激光测距的最小功率为0.015 W。天琴计划激光测距台站已具备白天和夜晚全时段常规卫星激光测距能力,将为今后天琴计划引力波探测卫星全时段激光测距奠定基础。

In order to analyze the satellite laser ranging(SLR)detection capability of the TianQin Laser Ranging Station,the laser energy(average power)is set as 0.15 mJ(0.015 W),0.4 mJ(0.04 W)and 4 mJ(0.4 W),respectively,to conduct laser ranging experiments on synchronous orbit satellites qzs2,compass i3 and compass i5 at night and daytime.Theoretically,the background noise of daytime skylight is analyzed,the effective echo rate of SLR under different aver-age power conditions is calculated.Finally the impact of average power on SLR detection capability is particularly ana-lyzed.In the experiment,the pitch angle of the telescope is fixed(E=50°),and the skylight background noise intensity is measured by rotating the telescope at different points.A superconducting nanowire single photon detector(SNSPD)with a detection efficiency of 60%(@1064 nm)is used,and background noise is suppressed by spatial filtering,temporal fil-tering and spectral filtering.Using 0.4 mJ(0.04 W)energy to perform laser ranging on the synchronous satellite in the daytime.Using 0.15 mJ(0.015 W)energy to perform laser ranging on the synchronous satellite at night.The Tianqin Laser Ranging Station has the capability of conventional SLR throughout the day and night,which will lay the foundation for the full-time laser ranging of the Tianqin plan gravitational wave detection satellite in the future.