激光雷达进行大气能见度探测时, 当探测路径上存在云、雾、烟尘或硬目标时, 大气消光系数会在局部发生显著变化, 表现为激光雷达回波信号在原有衰减趋势上出现突变。受此影响, 直接使用现有算法将导致能见度反演精度低或错误反演。为此提出一种将突变点定位、消光系数边界值确定、消光系数迭代反演相结合的能见度反演算法。首先查找、定位突变信号所在位置; 然后剔除突变点, 利用斜率法得到消光系数边界值; 最后基于Fernald法, 以迭代方式反演大气消光系数及能见度。对两种典型大气消光模式的仿真实验表明, 该算法提高了能见度反演精度, 能够获得更为准确的全局能见度。利用自行研制的激光雷达能见度仪实测回波数据也验证了该算法的有效性。

When lidar is used to detect atmospheric visibility, if cloud, fog, smoke, dust or the hard target exist in the detection path, the atmospheric extinction coefficient will change significantly in the local area, then the lidar return signals occur mutate against the original attenuation trend along with distance. Affected by it, using existing algorithm directly will cause the accuracy of visibility inversion low or wrong inversion. A combination visibility inversion algorithm including breakpoint location, extinction coefficient boundary value determination, extinction coefficient iterative inversion was proposed. Firstly, the breakpoint signal was found and located; Secondly, breakpoint was excluded by using slope method to acquire extinction coefficient boundary value; Finally, atmospheric extinction coefficient and visibility based on Fernald algorithm were inverted. According to the simulation experiments of two kinds of typical atmospheric extinction model, the accuracy of visibility inversion is improved, the more accurate global visibility is obtained. The validity of the proposed algorithm is also been verified by using real return signals of the lidar visibility meter developed by ourselves.