The Automatic Transmitter And Receiver System Of The Middle And Upper Atmospheric Lidar

The lidar,a high-precision remote sensor device,is widely applied in the middle and upper atmospheric detection.To ensure the middle and upper atmospheric lidar's best detection effect,the laser beam direction always needs to be adjusted to exactly match the field of view(FOV)of the telescopes before lidar begins to work every time.After identifying the previous technical bottlenecks,the automatic transmitter and receiver match is achieved by the three schemes based on CCD imaging,based on the gyroscope,and based on the self-adaptive in this thesis.The advantages and scope of application of these schemes are also analyzed respectively.The three systems,based on these schemes,are developed.The major works of the thesis are as follows:(1)The laser beam photos taken with a high-resolution CCD camera are analyzed by using image processing techniques.The position shift between the real-time position of the laser beam and preset standard is obtained by the pixel distribution.The transmitter and receiver match is quickly accomplished according to the position shift.(2)The posture is detected by a high-precision gyro sensor which is fixed on the electronically controlled mirror frame.The transmitter and receiver match is quickly achieved by adjusting the mirror frame according to the posture difference of the mirror frame between the practical tested and pre-installed.(3)The effective signal interval is adaptively selected according to the signal-tonoise ratio of the measured signal.It adaptively updates the adjustment step according to the current position's matching state and uses the correlation coefficient's increasing gradient as the adjustment direction.Self-adaptive match algorithm for transmitter and receiver is quickly realized.The above three systems are respectively implemented on experiments for serval times in Wuhan and Yanqing lidar station.The results suggest that these three systems can meet the observation.However,the self-adaptive matching system is the best solution when it comes to complex application situations.These work in this thesis will provide some technical support for the rapid commercial operation of atmospheric detection lidar and offer a new method to lidar's unattended and intelligent operation.