基于双边带调制的频率扫描干涉型激光测距技术

Laser Ranging of Frequency Scanning Interferometry System Based on Double-sideband Modulation

提出并论证了一种基于双边带调制的双扫频干涉测距技术,利用电-光双边带调制产生的-1和+1阶边带分别作为扫描方向相反的两个扫频信号,在接收端各获得一个频率与相对距离相关的拍频信号,通过将这两个拍频信号相乘的方式来减小由光路中扰动引起的测量误差.利用Optisystem软件进行系统仿真,结果表明,该方法能够有效抑制由于光路中扰动产生的测量误差.设计了实验验证系统,在光路中引入小幅振动作为扰动时,该方法对扰动的抑制比超过14dB,有效地提升了测距准确度.

A laser ranging of dual-sweep frequency scanning interferometry system based on doublesideband modulation was demonstrated.The electro-optic double-sideband modulation was used to create dual swept signals with opposite scanning directions.For each receiving terminal,the beat frequency signal related to relative distance was obtained.By multiplying both beat signals,measurement errors caused by disturbances in the optical path could be greatly reduced.The system was simulated in Optisystem.The simulation results indicate that the variations in the optical path length are eliminated efficiently.In addition,an experimental structure was proposed with vibrations in the optical path length.The experimental results show that the vibrations are suppressed for over 14 dB,which indicates that the precision can be improved effectively.