1/2波片对机载激光雷达偏振探测影响的研究

利用平面平行板模型和晶体膜层理论定量分析了1/2波片对机载激光雷达回波信号偏振探测的影响。计算结果表明:当入射光波长为532nm时,1/2石英波片对机载激光雷达回波信号平行分量与垂直分量透过率比值的影响幅度为0.82～1.196,1/2方解石波片对机载激光雷达回波信号的平行分量与垂直分量透过率比值的影响幅度为0.86～1.27;若用1/2石英波片测得的k=1.2,当考虑石英波片对五的影响时,则偏振探测两通道k的真实值应在1.003～1.463之间;若用1/2方解石波片测得的k=1.2,当考虑方解石波片对k的影响时,偏振探测两通道k的真实值应在0.945～1.395之间。由于1/2波片对k的影响,使机载激光雷达反演得到卷云等探测目标的退偏振比有较大的系统误差。

Study about the impact of 1/2 retardation sheet on the polarization sounding of airborne lidar

The impact of 1/2 retardation sheet on the polarization sounding backward scatter signals of airborne lidar is quantificationally analyzed by using of plane parallel plate crystal membranous theory.Calculating results reveal:the impact ranges of 1/2 quartz retardation sheet on transmission of parallel component and perpendiculal component of airborne lidar back- ward scatter signals are 0.82～1.20;the impact ranges of 1/2 calcite retardation sheet on transmission of parallel component and perpendiculal component of airborne lidar backward scatter signals are 0.86～1.27;if k value is 1.2 by using of 1/2 quartz retardation sheet,k reality values of polarization sounding channels are in the ranges of 0.99～1.41 when take into account of the impact of the 1/2 quartz retardation sheet;if k value is 1.2 by using of 1/2 calcite retardation sheet,k reality values of po- larization sounding channels are in the ranges of 1.03～1.52 when taking into account the impact of the 1/2 calcite retardation sheet.There is biggish system error on the depolarization ratio of cirrus etc when the airborne lidar detects cirrus etc.