双光学频率梳的多波长外差干涉测距方法的距离不确定度影响因素研究

Research on Influencing Factors of Distance Uncertainty in Multiwavelength Heterodyne Interferometric Distance Measurement Method Based on Dual-Optical Frequency Comb

装备精密制造、空间导航定位和卫星编队等领域要求激光干涉仪的测距精度在几千米到几百公里范围内达到pm量级,这是传统激光测距技术无法达到的。因此,利用等间隔多光谱光频梳特性,基于多波长激光干涉测量原理和双光学频率梳外差干涉测距数学模型,研究相位测量不确定度、空气折射率不确定度和信号重复频率引起的不确定度等因素对距离测量不确定度的影响。结果表明:距离测量不确定度会随温度的增加、压强的增大、二氧化碳体积分数的升高而减小;相比传统光学频率梳干涉测距法,温度越高、压强越大,双光学频率梳外差干涉测距法的距离测量不确定度下降越明显,当二氧化碳每立方米的体积分数在0.75%~0.80%范围内时,两种方法的距离测量不确定度趋于一致。

In the fields of equipment precision manufacturing,space navigation,positioning,and satellite formation,the accuracy of the laser interferometer measurement system is required to reach the pm level in the measurement range of thousands of meters to hundreds of kilometers,which is a requirement that cannot be achieved by traditional laser ranging technology.To solve the above issues based on the characteristics of equally spaced multispectral optical frequency combs,classic principle of multiwavelength laser interferometry,and theoretical mathematical model of the heterodyne interferometric distance measurement method of the dualoptical frequency comb,the effects of phase measurement uncertainty,air refractive index,and the uncertainty caused by signal repetition frequency on distance measurement are investigated in this paper.The results show that the uncertainty of distance measurement decreases with the increase in temperature,pressure,and carbon dioxide volume fraction.In addition,compared to the traditional optical frequency comb interferometric ranging method,the higher the temperature and pressure,the more obvious the decrease of the measurement distance uncertainty of the dualoptical frequency comb heterodyne interferometric ranging method;when the volume fraction of carbon dioxide per cubic meter is in the range of 0.75%-0.80%,the distance measurement uncertainty of the two methods tends to be consistent.