飞秒光梳的出现为实现高精度绝对距离测量提供了诸多有效方法,并有望直接应用于激光雷达、卫星编队飞行和空间引力测量等空间探测任务.从未来空间精密测距的精度需求出发,提出在飞行时间法辅助测距的基础上利用光学脉冲互相关分析技术将目标距离测量直接溯源到光梳重复频率的测量方法,建立了飞秒光梳测距基本模型,进行了飞秒脉冲互相关理论分析,并开展了互相关及测距仿真实验.仿真结果表明,在目标距离为10 km 以及重复频率扫描精度0.01 Hz条件下,进行非模糊量程内线性测距的测量精度优于450 nm,测距残余误差的峰谷(PV)值为780 nm,验证了该方法实现亚微米级甚至纳米量级大量程空间精密测距的可行性.

The advent of femtosecond optical frequency comb (FOFC) offers many available solutions for absolute distance measurement,as is expected to be directly applied to many space ranging tasks,such as laser radar,satellite formation flying and gravity field measurement.With a purpose of precision requirement for future space ranging,an integrated method based on time of flight method and optical pulse cross-correlation analysis is proposed,making the distance traceable to the repetition rate of frequency comb.The fundamental model for laser ranging with FOFC is built,theoretical analysis for femtosecond pulse cross-correlation is implemented,and simulations for cross-correlation and large-scale ranging are demonstrated.The simulation result shows that when the target distance is near 10 km and the scanning precision for repetition rate is 0.01 Hz,the measurement accuracy is better than 450 nm within the linear test of a non-ambiguity range,and the peak-valley (PV) value of residual errors is less than 780 nm,validating that the proposed scheme is feasible for large-scale space ranging with submicron precision or even nanometer precision.