超高重频卫星激光测距时序电路实现及应用

高重频卫星激光测距(Satellite Laser Ranging,SLR)具有精度高、捕获快、观测数据量大、可靠性高等优势。但随着重复频率提升至百千赫兹以上,现有测量时序电路无法达到系统运行处理速度和实时后向散射规避等要求。本文提出超高重频卫星激光测距时序电路设计方法,采用FPGA代替控制计算机进行门控距离实时计算,精确产生门控信号控制探测器开启,并使用了收发交替的方式实时调整激光点火信号以规避后向散射干扰。能够自主完成激光测距中距离门控输出时刻的计算、存储和信号输出,最高工作频率大于500kHz,满足百千赫兹超高频率测距的要求。该系统已成功应用于上海天文台100kHz重复率SLR,标准点精度突破200μm,验证了基于FPGA的测距时序电路的正确性和潜力。该电路设计简单、分辨率高、上位机交互方便,为百kHz～MHz的超高重频SLR系统时序控制电路设计提供有效解决方案。

Implementation and application of timing circuit for ultrahigh repetition frequency satellite laser ranging

High frequency Satellite laser ranging (SLR) has the advantages of high accuracy,fast capture,large amount of observation data and high reliability.However,as the repetition frequency increases to more than 100 kHz,the existing measurement timing circuits cannot meet the requirements of system operation processing speed and real time backscatter avoidance.In this paper,a design method for ultra high frequency satellite laser ranging timing circuits is proposed,using FPGAs instead of control computers for real time calculation of gating distances,accurately generating gating signals to control the detector open,and using an alternating transceiver to adjust the laser ignition signal in real time to avoid backward scattering interference.It can independently complete the calculation,storage and signal output of the distance gating output moment in laser ranging,and the highest working frequency is more than 500 kHz,which meets the requirement of 100 kHz ultra high frequency ranging.The system has been successfully applied to the 100 kHz repetition rate SLR at Shanghai Observatory,and the standard point accuracy exceeds 200μm,which verifies the correctness and potential of the FPGA based ranging timing circuit.The circuit is simple in design,high in resolution,and easy to interact with the host computer,which provides an effective solution for the design of the timing control circuit of the ultra high repetition rate SLR system from 100 kHz to MHz.