1550nm激光测风雷达相干探测的实验研究

发布时间：2018-03-27 20:40

本文选题：激光测风雷达　切入点：相干探测　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：本论文主要研究了相干激光测风雷达采用光纤接收时，光学系统结构及各参数之间的关系及对系统接收能量的影响，分析了固定焦距的光学系统在目标距离不同时对相干探测的影响，并进行了相关的实验，实验分析了收发合置对探测的影响以及改变光学系统口径和焦距对探测的影响。本论文的主要内容有：首先，简要介绍了激光测风雷达实现测风的原理、相干探测的基本原理，建立了激光测风雷达方程和信噪比方程，讨论了透射式和反射式天线以及收发合置和分置的优缺点，并利用几何光学分析了物象位置与大小之间的关系。然后，利用天线定理讨论了激光测风雷达发射与接收光学系统各参数之间的关系，讨论了采用光纤接收时对光学系统的要求。分析了收发合置的工作原理，对比了空间合束与光纤合束的异同。接着研究了光学接收系统对不同距离目标探测时，，对应的最小光斑位置及大小的变化关系，并对光纤的接收效率和接收能量进行分析。讨论了光学接收系统口径、相对孔径、光纤接收器的数值孔径以及光纤接收效率和能量之间的相互制约关系。然后通过ZEMAX进一步分析了光学接收系统对光纤接收的影响，进一步验证了上述分析。最后，进行了相干激光测风雷达实验，得到了93m距离内的硬目标回波信号，实验分析了收发合置光学系统对探测的影响。通过拆掉二级扩束镜头改变系统焦距及接收孔径，实验验证了上述理论分析。
[Abstract]:In this paper, the relationship between the structure and parameters of the optical system and the influence on the receiving energy of the coherent lidar are studied. The influence of fixed focal length optical system on coherent detection at different target distance is analyzed, and relevant experiments are carried out. The influence of the transceiver combination on the detection and the influence of changing the aperture and focal length of the optical system on the detection are analyzed experimentally. The main contents of this thesis are as follows:. Firstly, the principle of wind measurement by laser wind measuring radar and the basic principle of coherent detection are briefly introduced. The equations of laser wind measurement radar and signal-to-noise ratio are established, and the advantages and disadvantages of transmission antenna, reflection antenna, transceiver combination and separation are discussed. The relationship between the position and the size of the object is analyzed by geometrical optics. Then, by using the antenna theorem, the relationship between the parameters of the transmitting and receiving optical system of the laser wind measuring radar is discussed, and the requirements for the optical system when the optical fiber is used are discussed. The working principle of the transceiver and receiver is analyzed. The similarities and differences between space beam and optical fiber beam are compared. Then, the relationship between the position and size of the minimum spot is studied when the optical receiving system detects the target at different distances. The receiving efficiency and energy of optical fiber are analyzed. The aperture and relative aperture of optical receiving system are discussed. The numerical aperture of the optical fiber receiver and the relationship between the efficiency and energy of the optical fiber receiver are restricted. The influence of the optical receiving system on the optical fiber receiver is further analyzed by ZEMAX, which further verifies the above analysis. Finally, the echo signal of hard target within 93 m distance is obtained by the experiment of coherent laser wind measuring radar. The influence of the transceiver optical system on the detection is analyzed experimentally. The focal length and the receiving aperture of the system are changed by removing the two-stage beam expander. The above theoretical analysis is verified by experiments.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN958.98

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