无人机机载激光多普勒测速仪研究与飞行验证  

Research and Flight Test on Airborne Laser Doppler Velocimeter for Unmanned Aerial Vehicles

作　　者：陈兰剑 席崇宾 周健[1,2] 聂晓明 金世龙 罗晖[1,2] Chen Lanjian;Xi Chongbin;Zhou Jian;Nie Xiaoming;Jin Shilong;Luo Hui(College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,Hunan,China;Nanhu Laser Laboratory,National University of Defense Technology,Changsha 410073,Hunan,China)

机构地区：[1]国防科技大学前沿交叉学科学院,湖南长沙410073 [2]国防科技大学南湖之光实验室,湖南长沙410073

出　　处：《光学学报》2023年第17期55-64,共10页Acta Optica Sinica

基　　金：湖南省自然科学基金(2021JJ30782)。

摘　　要：无人机(UAV)通常利用全球导航定位系统(GNSS)提供的速度、位置等信息来保障其飞行安全,但GNSS的信号在复杂的城市环境中容易因高楼、树木遮挡等原因丢失,而机载激光多普勒测速仪(LDV)有望实现UAV的全天时独立高精度速度测量,从而保证导航信息的连续性。从目前实现机载LDV研制存在的瓶颈出发,通过理论分析和仿真计算,提出利用光学变换系统对机载LDV的工作距离进行拓展的方案;并对变换系统的参数进行了优化,集成了工作距离定标为50 m、测量景深为10 m的单波束机载LDV样机,将其搭载在UAV上进行了110 s的飞行实验。实验测得的UAV飞行速度经过俯仰角修正后,与GNSS记录的参照速度基本一致。飞行过程中样机输出的速度信号保持了较高的多普勒信号品质因子,初步验证了机载LDV的可行性和有效性,为后续机载LDV在UAV组合导航中的应用奠定了基础。Objective Unmanned aerial vehicles(UAVs)have emerged as a versatile platform for a wide range of civil applications,and offer flexibility and convenience in performing various tasks,like mapping,investigation,and patrolling.Accurate navigation information such as velocity and position is required to ensure the flight safety of UAVs.However,the global navigation satellite system(GNSS)is easily denied in urban environments due to the occlusion of tall buildings,which results in navigation information loss.Inertial navigation systems(INSs)are also hard to be relied on for long-scale autonomous navigation as its error accumulates over time.High-precision and independent velocity measurement methods will be beneficial for the navigation of UAVs.The laser Doppler velocimeter(LDV)has been applied to the integrated navigation of land vehicles improving localization accuracy.There is a bottleneck for LDV deployment on UAVs due to the limited working distance of LDV which is typically restricted to only a few meters.However,UAVs often operate at flight heights of dozens of meters,posing a challenge for LDV integration and utilization.Methods The carrier-to-noise ratio(CNR)of LDV is analyzed concerning coherent Doppler wind lidar since both of them are coherent detection systems.For the same LDV,the CNR can be improved by reducing the size of the probe beam spot on the target.On this basis,we propose a solution to the bottleneck of implementing airborne LDV by an optical transformation system to extend the working distance of LDV.The optical transformation system comprises a concave lens and a convex lens.By passing the Gaussian probe beam through this system,the size and location of the beam waist can be adjusted by varying the distance between the two lenses.Simulation and experiments show that the size of the transformed waist can be reduced without changing the transformed location of the waist by a probe beam with a larger waist size in the optical transformation system.Before the airborne LDV prototype is assembled,th

关 键 词：光学测量 激光多普勒测速仪 测速导航 无人机 

分 类 号：TN249[电子电信—物理电子学]