The facilities and performance of TianQin laser ranging station

Caishi Zhang, Tianquan Gao, Yuyan Cao,Zhongwei Fan, Honglin Fu, De-Feng Gu, Xida Han,Yutao Huang, Lin Kang, Ke Li, Ming Li, Rongwang Li, Yu-Qiang Li, Zhulian Li, Zun-Biao Li, Jun-Xiang Lian,Junchi Liu, Qi Liu, Sheng-Qian Liu, Yuan Liu, Jianwei Mei, Xiaoyu Pi, Cheng-Gang Shao, Ji Sun,Yu-Jie Tan, Yuhua Tang, Liang-Cheng Tu,Panpan Wang, Saijin Wang, Peiheng Wu, Qinglin Wu, Liang Xiong, Yao-Heng Xiong, Chao Xue, Yong Yan,Shan-Qing Yang, Hsien-Chi Yeh, Dongsheng Zhai,Haitao Zhang, Hongbo Zhang, Labao Zhang,Lihua Zhang, Hong-Chao Zhao, Guo-Dong Zhou, Jun Luo

Abstract: The TianQin Project is aiming at gravitational wave (GW) detection in space. TianQin GW observatory comprises three satellites orbiting on 1 × 105 km Earth orbits to form an equilateral-triangle constellation. In order to minimize the variations in arm lengths and breathing angles, the satellites must be launched and adjusted precisely into an optimized orbit. Therefore, satellite laser ranging must be used to enhance the precision of satellite orbit determination. To develop the capability of satellite laser ranging for TianQin’s orbit, the TianQin Laser Ranging Station has been designed and constructed to perform high-precision laser ranging for TianQin satellites and lunar laser ranging as well. Applying a 1064 nm Nd: YAG laser with 100 Hz repetition frequency, 80 pico-second pulse duration, and 2 × 2 array of superconducting nanowire single-photon detectors, we have obtained the laser echo signals from the five lunar retro-reflector arrays, and the measurement data have been packaged into 234 normal points (NPs), including a few data measured during the full-moon lunar phase. Each NP is calculated from continuous measurement for about ten minutes and the statistical error of the NPs is about 7 mm (1σ).