在分析星载傅里叶变换红外光谱仪干涉图的噪声特性后,提出一种抑制脉冲噪声的方法。计算以干涉图的采样点、相对零光程差得到的对称点、两侧采样点后,对得到的插值点建立参照值,通过与阈值比较确定脉冲噪声位置。实验表明,所提方法可以将光谱相对偏差由0.24%抑制到0.17%,将噪声等效辐亮度差由0.069 mW·m -2·sr -1·cm抑制到0.056 mW·m -2·sr -1·cm。所提方法在抑制脉冲噪声的同时保留了有效光谱信息,提高了星载傅里叶变换红外光谱仪的探测灵敏度。

为了实际测量、验证光学遥感卫星的杂散光抑制能力, 分析某些特殊卫星的成像轨道和时间特点, 研制了一套基于7维大型机器人的光学遥感卫星杂散光扫描测试系统。根据卫星全年太阳照明几何条件, 通过建立的光束扫描子系统各机构的控制方程构建照明光束的扫描位置、方位角(-90°~+90°)和俯仰角(-29°~+42.5°), 精度分别达到10 mm、0.2°和0.1°。消光子系统采用反射率低于1.5%(400~1 600 nm)的材料和大消光比结构, 极黑目标模拟器消光比可达9.9×10-7。研制的光学遥感卫星杂散光扫描测试系统能够满足目前大部分光学遥感相机的杂散光测试、分析和验证要求。

为模拟大面积空间太阳光辐照环境, 提出一种新型投影式太阳模拟系统设计方法。根据光学扩展量理论分析系统的能量传递过程, 采用4个短弧氙灯阵列作为光源, 设计物方远心投影系统以实现大面积均匀照明。通过Zemax软件模拟仿真及实际系统测量来验证系统设计的合理性。实验结果表明: 太阳模拟器的有效辐照面尺寸为1000 mm×1000 mm, 辐照度可达1263 W/m2, 且辐照面不均匀度优于±4.82%。该研究可为卫星载荷的空间环境实验提供准确可靠的太阳光辐照, 弥补传统大型太阳模拟器体积大、造价高的局限。

Lower tropospheric water vapor measurements are performed at nighttime using the mobile atmosphere monitoring lidar-2 (AML-2) which is operated by the Anhui Institute of Optics and Fine Mechanics. In this lidar system, a 354.7-nm light from a Nd:YAG laser is used as stimulating source, whose Raman shifted center wavelengths are at 386.7 and 407.5 nm for nitrogen and water vapor, respectively. We present a novel and convenient method for determining the Raman lidar calibration constant according to the scanning performance of this lidar. We are likewise able to realize the measurement of water vapor profile in the low troposphere. The error induced by the uncertainty of calibrated constants is within 7% for the Raman lidar system. Experimental results from two months of study indicate that the method of calibrating the lidar system constant is feasible, and the Raman lidar performance is stable and reliable.

The laser-induced fluorescence (LIF) characteristic of plant is directly linked to the photosynthesis. The LIF lidar for remote monitoring of plant has been suggested as one of the useful tools to identify plant species and determine its physiological status for a long time. So recently a LIF lidar for remote sensing of plant in Anhui Institute of Optics and Fine Mechanics is developed. It transmits laser beam at wavelength of 354.7 and 532 nm, and receives elastic echo and fluorescence echo at wavelength of 680 and 740 nm. Numerical simulations are carried out to determine achievable lidar performance including operation range. Validity of fluorescence signal is certified and then some results are presented. Comparison of the fluorescence characteristic among birch, conifer, and algae show that the °uorescence lidar is one of the potential tools to differentiate plant species.

在拉曼(Raman)激光雷达探测CO2实验中所采集的拉曼回波信号具有比较大的统计误差,有效减小统计误差,获得较高的探测精度是非常重要的工作。利用自适应滤波器对拉曼回波信号分段进行数据处理,可得到在分段的各个空间间隔内的随距离几乎不变的CO2混合比统计误差,经过自适应滤波器对信号进行处理后,Raman激光雷达对合肥地区夜晚CO2气体浓度探测达到比较高的测量精度,在1.5-5 km高度范围内,CO2浓度统计误差最大为2.5%,5-8 km统计误差最大为5%,8-10 km统计误差最大为10%。利用此技术也可以量化估计在较高的空间分辨率下满足探测精度要求的激光脉冲数。

大气折射率是影响光电探测领域测量精度的重要因素。为了提高光电测量精度,提出利用纯转动拉曼激光雷达信号反演低层大气折射率廓线的方法。通过接收N2和O2的纯转动拉曼回波信号,由双光栅单色仪分光后获得高低量子信号。根据高低量子信号的比值反演得出大气温度和大气压强廓线,从而获得大气折射指数垂直分布。通过与折射指数理论模型相比较,表明纯转动拉曼激光雷达反演对流层折射指数有较高的精度。给出了多组折射指数廓线的反演结果,得出多天夜晚不同时刻折射指数的特性。结果表明一天中不同时刻折射指数变化较小,7.5 km内最大相对误差约为0.4%; 不同月份之间折射指数波动较为明显,4.5 km内相对误差可达3.5%左右。

介绍了拉曼差分法测量对流层底部污染物O3的基本原理。计算和研究了N2,O2的拉曼光谱强度分布特征,利用O3对N2,O2紫外波段拉曼散射光的不同吸收特性,推导出O3浓度反演公式; 设计了拉曼差分激光雷达(Raman-DIAL)系统,该系统采用双通道分别接收N2和O2对紫外266 nm激光的拉曼散射光,通过拉曼差分法反演大气中O3浓度。分析了激光雷达系统噪声的来源,对双通道滤光片提出了相应的要求; 分析了大气中污染物SO2,NO2在紫外波段的吸收特性对拉曼差分法测量O3的影响及造成的相对误差; 利用差分激光雷达AML-2测得的O3数据模拟了拉曼差分激光雷达系统N2与O2的拉曼信号,从而证实了该方法探测对流层底部大气臭氧含量垂直分布的可行性。