北斗系统短基线解算数据处理方法

北斗卫星导航系统基线解算和高精度定位中的关键问题是整周模糊度解算。针对北斗系统的相对定位问题,该文利用B1、B2载波相位观测值组成宽巷双差观测值,利用搜索算法固定宽巷双差整周模糊度,建立宽巷及B1、B2的双差观测方程,并利用搜索算法固定B1的整周模糊度,进而固定B2的整周模糊度。以武汉大学PANDA软件处理结果作为参考值处理16km以下的四段基线进行算法的试验检验,结果表明,四段基线在E方向、N方向、U方向的精度分别为1.5cm、2.0cm、5.0cm,验证了利用宽巷组合观测值进行北斗系统基线解算是可行的,其精度和GPS系统相当。     

FirCAR算法的OTF快速定位方法

根据GNSS不同频率间整周模糊度的约束关系,提出一种基于多频整周模糊度间关系约束的模糊度新算法(dual-frequency integer relationship constrained ambiguity resolution,FirCAR)。FirCAR可快速动态解算出高高度角卫星的整周模糊度,将已经固定的整周模糊度视为高精度的伪距观测值应用到下一步的浮点解重算中。结合模糊度搜索算法,如LAMBDA,在模糊度搜索方面的高效性,根据重算后的浮点解进一步解算其他未固定的模糊度解。模糊度固定成功后,即可实现OTF(on the fly)快速定位。实测数据表明,FirCAR算法在静态和动态观测条件下,模糊度初始化所用的平均观测历元数分别为1.04和1.10。与常规的模糊度搜索算法的对比试验表明,结合FirCAR算法模糊度固定所用的观测历元数分别减少了39%和18%。     

基于整数小波和非负有序独立成分分析的遥感影像融合

结合ICA算法可以去除高阶冗余信息和IWT具有多分辨率、运算速度快的特性,在非负性条件的约束下,提出一种基于整数小波变换和非负有序独立成分分析(IWT-ONICA)的遥感影像融合方法。将该方法用于全色影像和多光谱影像的融合,数理统计(峰值信噪比、扭曲度、熵等)和目视判读结果表明,该方法融合效果优于其他方法,融合结果更加清晰,可视性更好。     

花岗岩体系中岩浆阶段金属组分的浓度(英文)

在岩浆阶段 ,富集金属元素最有效的机制是流体熔体的分离。受到硅酸盐熔体中盐的溶解度的限制 ,这种分离实为一个天然结晶过程的产物 ,所以必然发生在岩浆结晶的最后阶段。含氟的花岗岩体系中的矿物相的关系是已知的 ,并已确定了一个宽的液相不混溶区 ,其中也包括霞石标准分子的成分。该体系的不同部分 ,由多种元素在共存的硅酸盐和氟化铝两种熔体间的分配就可以得知。在这些实验中首次确定出元素分配与体系成分间的关系。这些数据也可解释一些经验数据所熟知的地球化学标志的变化。     

矿物—熔体间元素分配系数资料及主要变化规律

本文提供了不同成分的8大类主岩(偏铝质(超)基性岩、过碱性(超)基性岩、偏铝质中性岩、过碱性中性岩、偏铝质酸性岩、过碱性酸性岩、过铝质酸性岩、超酸性岩)中28个矿物(橄榄石、单斜辉石、斜方辉石、角闪石、黑云母、金云母、斜长石、钾长石、石英、磁铁矿、钛铁矿、石榴石、锆石、磷灰石、绿帘石、黄玉、榍石、堇青石、蓝方石、石榴石、霞石、白磷钙矿、镁铁钛矿、板钛矿、黄长石、钙钛矿、尖晶石、金红石)的69个化学元素(Li、Rb、Cs、K、Na、Ca、Sr、Ba、Mn、Fe、Mg、Cu、Pb、Zn、Co、Ni、Be、La、Ce、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Y、Sc、Cr、In、Ga、Al、B、Cd、Sb、Bi、U、Th、Zr、Hf、Si、Ti、Ge、Sn、Mo、Nb、Ta、W、V、P、F、Cl、S、N、O、C、As、Pu、Re、Os、He、Ne、Ar、Xe、Kr)和1个化学一价原子团OH的分配系数。综合分析对比表明,矿物、熔体的成分和结构是分配系数的最重要的控制因素。对前人未讨论过的矿物结构和熔体铝过饱和度这两个因素应引起重视。最后,本文分析了矿物-熔体间元素分配系数的研究现状、存在问题,指出了这一领域今后的研究方向。     

TDR detection of nonaqueous phase liquids in sandy soils using the eigendecomposition method

In this study, the presence of nonaqueous phase liquids (NAPL) in sandy soils are detected using a TDR probe system and the eigendecomposition method of analysis. As a demonstration, five NAPLs with different physicochemical properties (acetone, benzene, heptane, trichloroethylene, and xylene; Table 1) were used. Samples were prepared in such a way that the soil pore fluid has different contents of deionized water and NAPLs. For each experiment, a pulse signal with known characteristics was used and reflected signals were captured by an oscilloscope and analyzed using the eigendecomposition method. Autoregressive modeling and singular value decomposition were used to calculate the eigenvalues. The most significant eigenvalues were identified based on their power spectrum. The relative eigenvalue of the first mode (Eow), which is a measure of the power carried by the signal, was calculated and correlated to NAPL type and content, and octanol water partition coefficient (log Kow). The results indicated that for the same NAPL content, as log Kow increases, Eow decreases due to increase of hydrophobicity. For the same log Kow, as the organic content in soil pore fluid increases, Eow increases due to decrease of dielectric properties of the pore fluids.     

Drag Partition for Regularly-Arrayed Rough Surfaces

Vegetation and other roughness elements distributed across a surface can providesignificant protection against wind erosion by extracting momentum from the flowand thereby reducing the shear stress acting at the surface. A theoretical model haspreviously been presented to specify the partition of drag forces for rough surfacesand to predict required vegetation density to suppress wind erosion. However, themodel parameters have not yet been constrained and the predictive capacity of themodel has remained uncertain. A wind-tunnel study was conducted to measure thedrag partition for a range of roughness densities and to parameterise the model inorder to improve its range of potential applicability. The drag forces acting on bothan array of roughness elements and the intervening surface were measured independentlyand simultaneously using new drag balance instrumentation. A detailed measure of thespatial heterogeneity of surface shear stresses was also made using Irwin sensors. Thedata agreed well with previous results and confirmed the general form of the model.Analysis of the drag partition confirmed the parameter definition = C_R/C_S(where C_R and C_S are roughness element and surface drag coefficients,respectively) and a constant proportional difference between the mean and maximumsurface shear stress was found. The results of this experiment suggest that the definitionfor m, the surface shear stress inhomogeneity parameter, should be revised, although thetheoretical and physical reasons for including this parameter in the model appear to bevalid. Best-fit values for m ranged from 0.53 to 0.58.     

基于遗传算法的整周模糊度解算方法

在卡尔曼滤波的基础上,利用高斯变换降低各整周模糊度之间的相关性,然后利用遗传算法进行搜索,提出了自适应遗传算法,改进了搜索效果,仿真结果表明,自适应遗传算法有更快的搜索速度和更强的鲁棒性.     

高分辨率遥感影像的实时压缩算法

针对遥感影像的特点 ,采用整数小波变换、最优比特平面编码和上下文相关熵编码 ,实现高分辨率光学遥感影像的快速压缩。该算法支持多分辨率、多信噪比的嵌入式码流结构 ,可实现从无损到有损任意码率或多种质量的图像编码。实验表明 ,该算法简单高效 ,可满足遥感影像远程传输中实时压缩的要求     

评价GPS相位模糊度整数解正确性的严密方法

针对如何评价模糊度整数解的正确性，指出了基于传统的假设检验理论的三步法存在的理论缺陷，介绍了模糊度归整域的概念和可容许整数估计的定义，并在Teunissen关于可容许整数估计原定义的基础上给出了更为严密的新定义。基于这个新定义，讨论了模糊度成功率的概念及其计算公式。