毫米波辐射计定标系统

研制了小口径天线毫米波辐射计自然变温智能定标系统，该系统实现了所有数据的自动采集与分析。利用该系统对8mm狄克式辐射计进行了定标实验，得到了该辐射计的主要性能和定标方程。对其进行的精度分析表明该定标系统的天线温度不确定度为1.0582K。     

中频衰减全功率辐射计校正四毫米频段噪声源

本文论述了4mm波段热噪声标准、气体放电嗓声源以及定标辐射计,讨论了全功率辐射计与Dicke辐射计的优缺点,建立了中频衰减全功率辐射计的定标系统,并对系统的平衡方程及误差方程进行了推导和分析。     

高精度低功耗光谱辐射计数据采集卡的设计

本文介绍了高精度、低功耗光谱辐射计数据采集卡的的工作原理、软硬件构成及设计方案。该数据采集卡不仅测量精度高、速度快、安全性好，而且有益于以此数据采集系统为核心的光谱辐射计向小型化、智能化方向发展。     

3mm波段改进型全功率辐射计

本文分析了全功率计和Ｄｉｃｋｅ辐射计的优缺点，提出了改善全功率辐射计输出幅度存在漂移的方法，使全功率制式的３ｍｍ辐射计成功应用于１．２Ｍ射电望远镜上，取得了初步观测结果。特别指出，该制式在实现太阳射电的快速测量方面，具有系统电路简单，预期软件编制容易的优点。已经模拟实验证明，系统可实现小于毫秒量级的快速测量。     

低旁瓣微波辐射计天线设计和应用

提出一种高灵敏度微波辐射计设计方法,它采用辐射计天线的低旁瓣和高主波束效率设计,通过降低辐射计的系统噪声温度(尤其是外部变化的天线噪声温度),实现系统的高灵敏度。给出了微波辐射计天线方向图的理论仿真和实验结果及系统灵敏度的测量结果。辐射计天线实测结果表明:二个波段的天线副瓣电平均低达-30dB,天线主波束效率均高于95%。微波辐射计系统的实测结果表明:新方法使辐射计实际测量达到0.05K的高灵敏度。该系统也可在大气遥感测量、人工影响天气、土壤水分测量等领域应用,为防洪抗旱提供实时的降雨特性资料,在雷达和卫星通讯等领域,应用于电波的中性大气折射订正。     

3mm波段中频比较辐射计的研究

叙述了3mm中频比较辐射计的工作原理、电路结构、特性分析及实验结果，研究表明，这种辐射计不需3mm开关，其稳定性优于全功率辐射计，而成本和尺寸均与全功率辐射计相差不大，完全可以满足小型化、实用化的需要。     

可见至近红外波段多通道偏振辐射计的研制

设计了一种多通道偏振辐射计,系统采用固定滤光片、旋转偏振片的方法获取目标多波段偏振信息,双集束结构将偏振辐射计的波段范围从可见扩展至近红外和短波红外.重点阐述了系统的结构原理及各个模块的设计与实现方法,给出了偏振辐射计检测积分球直接输出和积分球加起偏器后输出光束的偏振度值,以验证偏振辐射计的偏振测量精度.检测结果表明,该多通道偏振辐射计的偏振测量精度优于2%,基本达到了系统设计要求.     

基于ARM的紫外辐射计测量控制系统设计

简要阐述了紫外辐射计的工作原理和应用领域。针对紫外辐射计使用方便快捷的工作需求,介绍了基于ARM处理器LPC2148的嵌入式系统的紫外辐射计测量控制系统设计方法,具体设计了紫外辐射计测量控制系统的硬件与软件。在系统调试中结合可变换能量的紫外光源进行测量,对紫外辐射计测量控制系统的设计方法的有效性得到了验证。ARM处理器硬件接口简单,软件编程方便,满足紫外辐射计使用方便快捷的工作需求。     

毫米波零中频全功率辐射计系统

提出了一种零中频接收的毫米波全功率辐射计系统,可降低外差式全功率辐射计系统实现的难度和成本,有利于实现系统的集成化和轻小型化。运用随机过程理论分析了全功率辐射计视频信号功率谱和温度灵敏度,在此基础上分析了零中频全功率辐射计的温度灵敏度。结果表明,在满足截止频率高于1/2视频积分滤波器带宽条件下,零中频辐射计中频通道可采用高通滤波器抑制直流漂移和低频噪声,而不会影响辐射计温度灵敏度,其理论值与射频带宽2倍于中频带宽的全功率辐射计相同。完成了一个34～40GHz毫米波多通道零中频全功率辐射计系统的设计和研制,采用10通道一体化集成和本振空馈功率分配技术,实现了系统的集成化和小型化,测试温度灵敏度与理论值相符,表明了理论分析的正确性和设计方法的可行性。     

综合孔径微波辐射计光学实时信号处理系统

分析了综合孔径微波辐射计光学实时信号处理系统的基本原理及关键技术,研制了一套X波段6单元综合孔径红外实时信号处理系统样机,并进行了系统测试及点辐射源的一维实时成像实验,获得了清晰的干涉条纹图像.初步的实验结果验证了综合孔径辐射计光学实时信号处理的可行性及系统设计的正确性.     

8mm波段直接检波式接收机研究

以弹载被动毫米阵列探测系统为应用背景，提出一种8mm波段直接检波式接收机，在论述其系统工作原理的基础上，对相关系统参数进行了分析与设计，方案性试验研究结果表明：这种辐射计具有灵敏度高、探测精度高和体积小等优点。     

基于受激参量下转换的红外标准传递辐射计定标技术

基于受激参量下转换过程产生光子的相关特性,构建了一套无需制冷且只利用可见光探测器即可实现红外标准传递辐射测量的系统。首先详细描述了该红外标准传递辐射计系统的工作原理,接着利用标准黑体拟合获取了该系统的定标系数,由此得到红外标准传递辐射计温度与待测黑体响应值的关系,最后通过与水浴黑体在相同温度点的响应值所反演获取的辐射温度作比较,进一步评估和验证了该红外标准传递辐射计系统的不确定度。实验结果表明:该红外标准传递辐射计测量水浴黑体辐亮度的联合不确定度为1.64%,表明该红外标准传递辐射计可作为标准黑体到用户传感器的传递标准。     

3毫米波十六通道焦平面辐射计数据采集与测试系统设计

为了研究无源毫米波成像特性,在毫米波辐射计成像系统理论和焦平面线阵扫描体制基础上,开发了3毫米波十六通道的辐射计数据采集与测试系统,给出了详细的硬件设计方案,实现了十六通道数据采集、传输、预处理和成像测试。最后通过成像试验,实现了7秒/帧的成像速率。得出的结论对研究无源毫米波实时成像具有指导意义。     

Experimental Research on Optimal Millimeter Wave Radiometric Images

Widely used in remote sensing and guidance, radiometer is a typical passive detection system. However, it is an important problem to improve the millimeter wave radiometric imaging resolution. On basis of discussing imaging theory of radiometer, this paper presents the way to get optimal radiometric images by experimental research. The experimental result shows the satisfying images can be obtained by the matching of the parameters.     

Simultaneous analysis of downlink beacon dynamics and skybrightness temperature. Part II. Extraction of amplitude scintillations

This paper addresses the long-standing problem of separating the tropospheric amplitude scintillations from the dominant trend of atmospheric attenuation in a satellite downlink. Following extensive theoretical and experimental work, it is shown how the use of a radiometer coaxial with the communications beacon receiver constitutes an excellent tool for an optimum separation regardless of the meteorological conditions along the propagation path and avoids the use of the long-traditional high-pass filter approach. The experimental and theoretical work has revealed that the angular resolution of the radiometer together with the dynamics of rain attenuation and tropospheric scintillations determine the success of the extraction. This is because fast fadings require large radiometer antennas in order to resolve the sky temperature fluctuations. The dynamic behavior of rain attenuation has been reanalyzed and adapted for this study with special focus on the Maseng-Bakken (MB) model and the impact of the slant path on attenuation dynamics. The importance of the antenna pattern in the time response of the radiometer is studied in detail and permits to derive the maximum Fourier component observable for a given antenna size. The theoretical work has been verified by means of extensive experimental results obtained using a dual radiometer system and a beacon receiver tracking the ITALSAT 39.5 GHz F40 beacon. Finally, because of its importance and direct relevance to future communication systems benefiting from fade countermeasure strategies, the minimum size of the radiometer antenna for a successful extraction of amplitude scintillations is determined as a function of the elevation angle and carrier frequency     

On the possibility of detecting avalanche victims by microwave radiometry

An experimental investigation has been made of the possibility of using a microwave radiometer to find humans covered by snow. When a radiometer operating at 1.4 GHz was moved along a track it registered a highly fluctuating radiation temperature of the snow covered ground. The increase in temperature when the radiometer passed over a human was so small that detection in general was impossible.     

Analysis and improvement of tipping calibration for ground-basedmicrowave radiometers

The tipping-curve calibration method has been an important calibration technique for ground-based microwave radiometers that measure atmospheric emission at low optical depth. The method calibrates a radiometer system using data taken by the radiometer at two or more viewing angles in the atmosphere. In this method, the relationship between atmospheric opacity and viewing angle is used as a constraint for deriving the system calibration response. Because this method couples the system with radiative transfer theory and atmospheric conditions, evaluations of its performance have been difficult. In this paper, first a data-simulation approach is taken to isolate and analyze those influential factors in the calibration process and effective techniques are developed to reduce calibration uncertainties. Then, these techniques are applied to experimental data. The influential factors include radiometer antenna beam width, radiometer pointing error, mean radiating temperature error, and horizontal inhomogeneity in the atmosphere, as well as some other factors of minor importance. It is demonstrated that calibration uncertainties from these error sources can be large and unacceptable. Fortunately, it was found that by using the techniques reported, the calibration uncertainties can be largely reduced or avoided. With the suggested corrections, the tipping calibration method can provide absolute accuracy of about or better than 0.5 K     

双通道自校准辐射计与辐亮度标准探测器的比对实验研究

基于自发参量下转换的高精度自校准辐射基准源是目前卫星遥感定标的研究热点。本文介绍了双通道自校准辐射计的工作原理并搭建了实验装置,展开了与传统辐亮度标准探测器的比对实验验证。采用736.9nm激光导入积分球的单色均匀辐亮度光源,将双通道自校准辐射计和辐亮度标准探测器分别对积分球出口辐亮度进行探测,测得绝对辐亮度分别为4.69×10-9W/(sr?mm2)和5.19×10-9W/(sr?mm2),二者之间的相对偏差为9.63％,验证了研制的双通道自校准辐射计的原理可行性。     

A Receiver in a Millimeter Wave Radiometer for Atmosphere Remote Sensing

A millimeter wave radiometer system with high resolution is described in this paper, which was used for remote sensing of integrated water vapor and integrated liquid water in the troposphere. A novel receiver technique was adopted in the radiometer system to deracinate an impact of the receiver gain shift on its precision and improve its performance. Measured results show that this radiometer system has enough stability in long time measurement and capability to measure atmospheric brightness temperature.     

TWO NEW TYPES OF MICROWAVE RADIOMETER: A COMPUTER GAIN COMPENSATIVE DESIGN AND A REAL-TIME CALIBRATED DESIGN

Long term stability is the main factor that influences the minimum detectable signal of microwave radiometers. Two new types of microwave radiometer were studied: a computer gain compensative microwave radiometer and a real-time calibrated microwave radiometer. The long term stability of both designs was optimal because they were insensitive to system gain fluctuations. The continuous calibrated microwave radiometer was also insensitive to system noise fluctuations. The minimum detectable signals were 0.13 and 0.19K respectively under an integration time of 0.6s.