一种有效的机载合成孔径雷达动目标成像方法

为实现机载合成孔径雷达(Synthetic Aperture Radar，简称SAR)实际回波数据中的运动目标聚焦成像，本文在用前置滤波法检测出运动目标的基础上，提出了利用目标子图像匹配方法来估计动目标的方位向速度，得到相应的运动目标聚焦参考函数，然后对运动目标进行聚焦成像，并给出了利用该方法得到的运动目标聚焦图像．成像结果表明，目标子图像匹配方法对动目标成像是有效的，易于工程实现，有实际应用价值．     

基于 NSCT 域特征和 PCNN 的SAR 图像目标分割

针对 SAR 图像的目标自动分割问题,在分析非下采样轮廓波变换和脉冲耦合神经网络的基础上,提出了一种基于非下采样轮廓波域特征图和 PCNN 的 SAR 图像目标分割算法.对 SAR 图像经过 NSCT 分解后的高、低频图像分别运用不同方式进行处理.对低频图用 PCNN 进行分割以获取目标所在的区域,对高频子带构造了特征图,对特征图利用 PCNN 进行分割以获取目标的精细结构.利用 MSTAR 数据进行了仿真实验,并与基于模糊 C 均值的分割算法、基于马尔可夫随机场的分割算法进行了对比.实验结果表明,所提出算法对 SAR 图像目标的分割结果更为准确,同时较其它算法具有更强的抗噪性能,是一种有效可行的 SAR 目标分割算法.     

基于点目标自动提取的机载SAR图像残余运动估计方法

对前期提出的估计单幅机载合成孔径雷达(SAR)图像中的残余运动误差的点目标多斜视方法(MTPT)进行了理论分析,并针对其存在的手工选点工作量大、受噪声影响严重的缺点,对其做了以下改进:在图像中自动选择点目标以减少工作量,并对所测得的相位进行滤波和加权平均以去除噪声,同时采用循环计算的策略来提高算法的适应性.实际的机载S...     

基于Hǒlder指数和ICA的海域SAR图点目标检测

本文将分形Hǒlder指数和信号分离相结合,利用独立成分分析技术（ICA,Independent Component Analysis）,实现了海杂波SAR图的散斑抑制和点目标检测。首先,计算点态Hǒlder指数图,并提出二值模糊方法对其处理;接着使用ICA技术得到该图的基图像和独立成分;提出空间分离法,对独立成分进行分离,同时对基图进行对应分类,获得非噪声和噪声两个空间。最后在非噪声空间上重构图像。实验部分,将该算法与传统算法进行对比,证实了该算法的有效性和优越性。     

一种修正的基于混沌预测误差的目标检测算法

基于混沌预测误差的目标检测算法是检测混沌背景下目标的算法.本文对该算法的检测结果进行了分析,分析结果表明其检测到的目标区域比实际的目标区域大.针对这个问题,对基于混沌预测误差的目标检测结果进行了修正,修正后的结果更接近于目标的真实大小.用Lorenz混沌系统产生的仿真数据和实测的机载海面合成孔径雷达(Synthetic Aperture Radar,SAR)图像进行了实验.实验结果与理论分析的结果一致,从而证明了理论分析的正确性.     

基于MAPES的非均匀多基线SAR三维成像算法

多基线合成孔径雷达(Synthetic Aperture Radar,SAR)通过在高度方向上的多次重复飞行形成了对目标观测的高度向合成孔径,具有高度向分辨能力,能够实现对目标的三维成像.本文针对各条轨迹非等间隔分布的多基线SAR数据,提出了基于缺失数据向量幅度和相位估计(Missing-data Amplitude and Phase Estimation,MAPES)的非均匀多基线SAR的三维成像算法.根据多基线SAR三维成像的信号模型和基于谱估计的三维成像原理,引人MAPES算法对非均匀采样的目标高度向观测数据进行空间谱估计,实现对目标的高程成像,从而得到了基于MAPES算法的非均匀多基线SAR三维成像处理流程.使用MAPES算法对非均匀多基线SAR的仿真数据和微波暗室数据进行了三维成像实验.     

基于SQP和GA法的油田地面集输管网参数优化研究

利用序列二次规划法（SQP算法）和遗传算法（GA）对油田地面集输管网的结构参数进行了优化。分别建立优化目标函数及算法，并利用胜利采油厂的胜坨油田和长庆采油三厂的靖南油田的两个集输管网的实际生产数据，分别采用SQP算法和遗传算法中的并列选择法和权重系数变化法进行管网最优管径的求解。结果表明，与SQP算法相比，采用遗传算法进行集输管网结构参数优化有更好的优化效果。     

测定空气流量的加权WT法

本文详细阐述一种测定管中空气流量的新方法，即加权的ＷｅｉｇｈｔｅｄＴｃｈｅｂｙｃｈｅｆ方法，简称ＷＴ法，它是在以往的Ｌｏｇ－Ｔｃｈｅｂｙｃｈｅｆｆ多点累加方法（简称ＬＴ法）的基础上，引入权重函数，将ＬＴ法中的两个分离模型统一为一个单一模型，本文以一个例子进行具体的计算。此外，对文（１）中的一些阐述和结果进行了必要的修正。     

用VB处理平板的平面度误差

本文介绍用Visual Basic语言设计的软件，主要用于平板平面检定的数据处理。软件针对常用的指示器测量和节距法测量（栅格布点和对角线布点），每种测量方法所获得的数据都分别用简易法（三远点平面法或对角线平面法），最小区域法进行评定。文中重点介绍了最小区域法的程序设计原理。     

无人机机载合成孔径雷达（SAR）定位方法综述

无人机机载合成孔径雷达（SAR）技术近年来发展迅速,成为一个研究热点。本文对无人机机载SAR定位中的多项式、Leberl、等效共线条件方程、直接定位、读图定位五种方法进行了研究,阐述了各种数学模型的应用前提,并对每种方法的适用性进行了探讨,最后指出了完善无人机定位方法的研究方向。     

Bistatic point target reference spectrum in the presence of trajectory deviations

The point target reference spectrum (BPTRS) of bistatic SAR in the presence of trajectory deviations based on Loffeld?s bistatic formula (LBF) is developed. The presented BPTRS is suitable for the general airborne bistatic configuration. For the air-borne bistatic SAR, both the transmitter and the receiver will contribute to the trajectory deviation. The compensation of trajectory deviations becomes more complex because of the separate locations of the transmitter and receiver. The authors focus on the effects of trajectory deviations on the point target spectrum of bistatic SAR. The proposed BPTRS is verified by simulation experiments performed in the azimuth-invariant configuration.     

Degrading effects of the lower atmosphere on long-range airborne synthetic aperture radar imaging

The imaging performance of airborne synthetic aperture radar (SAR) systems has advanced to the point that the effects of clear-air refractive index perturbations cannot be ignored. Operating at long ranges, and low grazing angles, in particular, require propagation geometries through regions of the lower atmosphere that may cause noticeable and, sometimes, severe degradation of the images. The range of image anomalies that can be attributed to the atmospheric boundary layer (ABL) is illustrated, the pertinent characteristics of the ABL is discussed, a first-order SAR imaging model that incorporates the refractive index perturbations associated with the ABL is developed and the magnitude of the image anomalies resulting from measured refractive index perturbations is estimated. The model predictions correlate well with the observed image anomalies and measured properties of the ABL. On the basis of theory and measurements, it is expected that the degrading effect of clear-air atmospheric refractive index perturbations is much more common than previously thought and may be a limiting factor for long-range SAR imaging performance.     

混合采样机载MIMO雷达成像方法

针对传统合成孔径雷达(SAR)在进行机动目标成像时,极易造成SAR图像中出现散焦与模糊现象,本文通过融合MIMO雷达单次快拍与SAR合成孔径技术,提出了一种混合采样高分辨率机载MIMO雷达机动目标成像方法。该方法利用目标与载机的空间位置信息进行运动补偿,而无需估计目标多普勒信息,因此,能够有效避免传统SAR存在的机动目标多普勒参数估计难题。仿真实验证实了新方法实现机动目标聚焦成像的有效性。     

Atmospheric CO2 measurements with a 2 μm airborne laser absorption spectrometer employing coherent detection

We report airborne measurements of CO(2) column abundance conducted during two 2009 campaigns using a 2.05 μm laser absorption spectrometer. The two flight campaigns took place in the California Mojave desert and in Oklahoma. The integrated path differential absorption (IPDA) method is used for the CO(2) column mixing ratio retrievals. This instrument and the data analysis methodology provide insight into the capabilities of the IPDA method for both airborne measurements and future global-scale CO(2) measurements from low Earth orbit pertinent to the NASA Active Sensing of CO(2) Emissions over Nights, Days, and Seasons mission. The use of a favorable absorption line in the CO(2) 2 μm band allows the on-line frequency to be displaced two (surface pressure) half-widths from line center, providing high sensitivity to the lower tropospheric CO(2). The measurement repeatability and measurement precision are in good agreement with predicted estimates. We also report comparisons with airborne in situ measurements conducted during the Oklahoma campaign.     

General adaptive-neighborhood technique for improving synthetic aperture radar interferometric coherence estimation

A new method for filtering the coherence map issued from synthetic aperture radar (SAR) interferometric data is presented. For each pixel of the interferogram, an adaptive neighborhood is determined by a region-growing technique driven by the information provided by the amplitude images. Then pixels in the derived adaptive neighborhood are complex averaged to yield the filtered value of the coherence, after a phase-compensation step is performed. An extension of the algorithm is proposed for polarimetric interferometric SAR images. The proposed method has been applied to both European Remote Sensing (ERS) satellite SAR images and airborne high-resolution polarimetric interferometric SAR images. Both subjective and objective performance analysis, including coherence edge detection, shows that the proposed method provides better results than the standard phase-compensated fixed multilook filter and the Lee adaptive coherence filter.     

Scalable algorithms for designing CO2 capture and storage infrastructure

Optimization and Engineering - CO2 capture and storage (CCS) is a climate change mitigation strategy that aims to reduce the amount of CO2 vented into the atmosphere from industrial processes....     

Four-laser airborne infrared spectrometer for atmospheric trace gas measurements

We describe the four-laser airborne infrared (FLAIR) instrument, a tunable diode laser absorption spectrometer designed for simultaneous high-sensitivity in situ measurements of four atmospheric trace gases in the troposphere. The FLAIR spectrometer was employed during the large-scale airborne research campaign on tropospheric ozone (TROPOZ II) in 1991 and was used to measure CO, H(2) O(2), HCHO, and NO(2) in the free troposphere where detection limits below 100 parts in 10(12) by volume were achieved.     

机载SAR天线稳定平台自动化测试系统

根据SAR(Synthesis Aperture Radar，合成孔径雷达)平台的工作原理和需要测试的关键性能，以PXI虚拟仪器为核心，使用二维电控转台模拟载机角运动，使用激光测量装置测量平台跟踪误差，设计了机载SAR天线稳定平台的新型自动化测试系统，介绍了系统的结构、软件构成及工作原理。     

线性调频脉冲串制式合成孔径雷达实时成像算法和方案的设计和模拟

介绍了线性调频(LFM)脉冲串制式合成孔径雷达(SAR)提高距离向分辨率原理,并且提出线性调频SAR的信号处理算法和步骤,避免了为提高距离向分辨率而加大系统带宽的问题.通过模拟验证了算法的正确性,并分析了计算量.设计了相应的SAR实时成像处理器方案,满足了这种新体制SAR系统的大规模成像处理的要求.