超高重复频率100kHz~500kHz卫星激光测距（SLR），具有回波密度大、目标搜索快、激光功率高等特点，是目前国际SLR技术发展的重要方向。激光在大气传输中的后向散射光干扰卫星激光回波接收，是限制超高重复频率SLR实现的重要因素。本项目提出低重复频率距离门控收发交替模式下以脉冲群方式实现超高重复频率SLR，距离门控先输出点火脉冲群触发激光器，群内含数百脉冲，再输出对应脉冲群触发开启单光子探测器接收回波。激光发射与回波接收时间交替分开，避开后向散射光的干扰，此时500kHz测距需要激光与单光子探测器交替工作在1MHz重复频率。基于上海天文台SLR系统平台，将1kHz/1W皮秒激光器改进至1MHz/10W输出，以具有1MHz响应的单光子探测器和事件计时器接收数据，研究脉冲群式500kHz数据实时处理技术，实现国内首次开展超高重复频率SLR的台站，为国内超高重复频率SLR发展与应用奠定基础。

Ultra-high repetition rate of 100kHz to 500kHz satellite laser ranging (SLR), which has advantageous characteristics of high laser echo density, target searched quickly, high laser power and so on, is an important direction for the development technology of international SLR. Laser echoes received from satellites are interfered by the back-scattered laser from the laser transmission in the atmospheric. That is an important limiting factor in the realization of ultra-high repetition rate SLR. A method of low repetition rate of laser emission and laser echoes received alternately with pulse trains under the control of range gating to achieve ultra-high repetition laser ranging is proposed in this project. The range gate puts out ignition pulse trains, which contains hundreds of pulses, and triggers the laser to emit pulse trains, and then puts out the corresponding pulse trains to trigger a single photon detector to receive pulse trains laser echoes from satellites. Thus, the time of laser emission and laser echoes received are separated alternately, so the laser echoes received from satellites avoid the interference of the back-scattered laser. At this time, the repetition rate of 500 kHz laser ranging requires the laser and single photon detector alternately work at the repetition rate of 1 MHz.Based on the Shanghai Astronomical Observatory SLR system platform, the repetition rate of 1 kHz picosecond laser with average power of 1W would be improved to a repetition rate of 1 MHz picosecond laser with average power of 10W. Under the single photon detector and event timer with response repetition rate of 1 MHz, pulse train laser echoes with data of 500 kHz would be detected under the technology of real-time data processing. Therefore, the Shanghai Astronomical Observatory SLR station would be the first one on ultra-high repetition rate SLR in China. This would lay the foundation for the development and application of ultra-high repetition rate SLR in our country.