非同轴激光雷达重叠因子的自校正系统设计

受振动，温度，预紧力变化等外部环境因素影响，激光雷达系统的激光发射光轴和望远镜接收光轴会发生变化，导致激光雷达系统的重叠因子发生变化，进而影响激光雷达系统的远场探测精度与探测稳定性。针对非同轴激光雷达提出开展重叠因子自校正的软硬件系统设计，采用二相电机驱动，具有自锁功能的蜗轮蜗杆发射光轴较正平台设计并搭建了激光发射光轴倾角调节系统，并以激光回波信号强度为校正判据寻找非同轴激光雷达系统收发光轴的最佳匹配位置。自校正过程采用粗扫描和细扫描相结合的方式，以实现校正精度和校正效率的综合考量，其中粗扫描采用环形扫时序，可在961 s内将激光发射光轴锁定在0.4 mrad×0.4 mrad倾角范围内；细扫描采用S形时序，可在441 s内实现激光发射光轴0.02 mrad的倾角调节精度。自校正前后的大气回波距离平方修正信号表明，设计的自校正系统能够实现非同轴激光雷达系统重叠因子的有效校正，并提升系统探测性能，为全天时，无人值守的激光雷达大气探测提供支持。

Design of self-alignment of geometric overlap function in the non-coaxial Lidar system

The relationship between the optical axes of the transmitter and the receiver of the non-coaxial lidar is affected by the external environment,such as vibration,temperature,pretightening force,etc. It leads to the geometric overlap variation of the lidar system.In further,the lidar detection accuracy and stability in far range is affected. To solve this problem, a hardware and software design of the self-alignment of geometric overlap function in the non-coaxial lidarsystem is proposed. The self-aligning system consists of a two-phase stepper motor driver, and a two-dimensional inclination adjustment platform. The laser echo signal strength is used as the correction criterion to find the best matching position of the receiving opticalaxis of the non-coaxial laser radar system. The combination of coarse scanning and fine scanning of self-alignment method is selected based on the comprehensive consideration of alignment accuracy and alignment efficiency. The coarse scan adopts the circular scanning,which can lock the transmitter optical axes within the inclination range of 0.4 mrad×0.4 mrad in 961 s. The fine scan adopts S-shaped scanning, which can achieve the inclination adjustment accuracy of 0.02 mrad in 441 s. The preliminary experiment results show that the RSCS of lidar echo signal after the self-alignment is distributed with the lidar equation, which presents an improved performance oflidar detection and can be applied for the all-day lidar measurement without man-made operation.