微波辐射计的功率非线性对标定天线温度的影响

微波辐射计通过两点定标反演天线温度依赖的是辐射计的输入功率与输出电压的线性关系。通过分析平方律检波器的输入功率与输出电压的关系，导出非线性系数与由口面定标法反演的天线温度误差的关系式。定量说明了功率非线性度引入误差的大小．通过计算分析得出两种定标系统（地面遥感和星载遥感）对功率非线性度的要求。     

Improved Near-Infrared Spectral Responsivity Scale

A cryogenic radiometer-based system was constructed at the National Institute of Standards and Technology for absolute radiometric measurements to improve detector spectral power responsivity scales in the wavelength range from 900 nm to 1800 nm. In addition to the liquid-helium-cooled cryogenic radiometer, the system consists of a 100 W quartz-tungsten-halogen lamp light source and a 1 m single-grating monochromator for wavelength selection. The system was characterized and the uncertainty in spectral power responsivity measurements evaluated. A variety of photodetectors, including indium gallium arsenide photodiodes (InGaAs), germanium (Ge) photodiodes, and pyroelectric detectors, were subsequently calibrated. Over most of the spectral range, the spectral power responsivity of the photodetectors can be measured with a combined relative standard uncertainty of 0.4 % or less. This is more than a factor of two smaller than our previous capabilities, and represents a significant improvement in the near infrared (NIR) spectral power responsivity scale maintained at NIST. We discuss the characterization of the monochromator-based system and present results of photodetector spectral power responsivity calibrations.     

用MFRSR仪器观测气溶胶光学厚度

气溶胶对激光大气传输有着重要的影响。MFRSR(多光谱旋转遮蔽影带辐射计)是一种用于地基辐射和气溶胶测量的仪器。该仪器使用自动旋转影带技术同时在七个波段交替进行总的水平辐射和漫射水平辐射测量,然后推算得出直接辐射。其中6个波段的中心波长分别是414.3nm,495.3nm,613.7nm,671.5nm,867.6nm,939.3nm,还有一个硅探测器进行宽波段太阳总辐射测量。本文首先介绍了MFRSR仪器及其定标和资料处理方法,然后利用香河观测站2004-2005年MFRSR观测资料,分析了气溶胶的统计特性。为了说明利用MFRSR观测气溶胶光学厚度的可靠性,我们将MFRSR与AERONET的观测结果进行了比较,结果表明二者在500nm、670nm和870nm三个波段的平均偏差分别为-0.021,-0.009,-0.004;标准差分别为0.067,0.051,0.050。文中还对造成二者偏差的原因进行了讨论。     

金源煤矿1321工作面冲击地压综合防治研究

金源煤矿1321工作面具有冲击地压倾向性,通过煤层高压注水,借助电磁辐射仪和钻屑法监测,结合深孔卸压爆破的综合防冲措施,安全生产20万t煤炭资源。     

综合孔径微波辐射计二阶量化数字相关器研究

微波辐射计作为一种无源遥感器,在遥感技术领域有着巨大的应用前景.传统的微波辐射计的空间分辨率受到天线孔径的限制.综合孔径微波辐射计利用了干涉测量原理和复相关技术,是一种可以有效地提高空间分辨率的新型辐射计.本文针对综合孔径微波辐射计的数字相关器进行了深入研究,分析论证了二阶量化数字相关器的工作机理,并对采用该种相关器的系统的信噪比进行了分析.初步的试验验证结果证明了该方案的有效性.     

用微波遥感技术对海底输油管道进行监测

对假定海底管道发生油溢事故时形成的空气、油膜和海水的组合体模型进行了详细分析,揭示了模型的辐射亮温与油膜厚度的关系、有效发射率增量与入射角之间的关系、不同频率下辐射亮温与油膜厚度之间的关系。得出,利用微波遥感技术检测海底管道泄漏及泄漏量、污染区域在理论上是可行的,并由此理论设计了机载微波辐射计,文章还介绍了该系统的组成结构和系统的优选方案,指出利用高精度微波辐射计架设在无人机上监测的优点。     

用辐射计进行低角电波折射修正的补偿方法

用微波辐射计进行电波折射修正是一种快速、精确的好方法。但由于它没有考虑电波射线弯曲所引起的折射误差,因此只适用在雷达天线仰角较高的条件,如在低仰角下使用该方法就会产生较大的误差。为了扩大其应用范围,本文提出了用微波辐射计进行低角电波折射修正的补偿方法,并且给出了精度检验结果。     

全极化微波辐射计系统中高速数字相关器设计

海面风场直接影响大气与大洋环流相互作用,是研究海流运动规律的必要条件.全极化微波辐射计是一种用于海洋表面风场测量的新型被动微波遥感器.数字相关器是全极化辐射计的核心部件.文中详细介绍了一种新型数字相关器的设计和实现.两片高速A/D转换器采样四路信号并通过XILINX公司新一代的FPGA-Vertex5作相关运算.同时本...     

Improved broadband solar irradiance from the multi-filter rotating shadowband radiometer

Approximations to total and diffuse horizontal and direct normal, broadband solar irradiance (280–4000 nm) can be obtained from the multi-filter rotating shadowband radiometer (MFRSR) using the unfiltered silicon channel of this seven-channel instrument. However, the unfiltered silicon channel only responds to wavelengths between 300 and 1100 nm and does not have a uniform spectral response. In contrast, the best, more expensive, first-class, thermopile-based radiometers respond fairly uniformly to all solar wavelengths. While the total horizontal and direct normal solar irradiance measurements made with the MFRSR unfiltered silicon channel are reasonable if carefully calibrated with a thermopile radiometer, the diffuse horizontal irradiance calibrated in this way has a large bias. These issues are common to all inexpensive, silicon-cell, solar pyranometers. In this paper we use a multivariate, linear regression technique for approximating the thermopile-measured total, diffuse, and direct broadband solar irradiances using the six, narrowband filters and the open-channel of an MFRSR. The calibration of the MFRSR for broadband solar by comparing various combinations of MFRSR channels to first-class thermopile instruments is illustrated, and methods to track the instrument response during field deployments are investigated. We also suggest an approach to calibrate the open-channel for all three components that could improve measurements that are made using typical, commercial, silicon-cell pyranometers.     

基于辐照度法的场地辐射校正试验研究——场地同步观测仪器的比较

２０００年９月在敦煌辐射校正场用国内外两组仪器同时获取场地数据,经数据处理分析后,对中巴地球资源一号卫星ＣＣＤ相机进行了绝对辐射定标。本文通过对试验数据的结果比对和误差分析,证明国产仪器完全能满足对中巴地球资源一号卫星进行绝对辐射定标的精度要求。