带约束条件的自适应滤波及其在GPS定位中的应用

推导了约束状态下的卡尔曼滤波递推方程,采用不消去状态参数的方法,在卡尔曼滤波的数学模型中增加约束状态方程推导出约束状态下的卡尔曼滤波递推方程.表明采用带约束条件的滤波递推过程与一般卡尔曼滤波递推方程相似,只要对预报值及其协方差增加一项约束条件改正项即可,因此,在滤波计算上不需要做大的修改.还讨论了带约束条件的卡尔曼滤波的自适应算法,说明一般自适应滤波算法同样适用于带约束条件的滤波,因此在应用上非常便利.利用一组GPS动态定位数据中的伪距观测值进行计算分析,并以距离作为一个约束条件,结果显示约束条件对滤波结果的改善程度与约束条件和动态系统本身有关.对于一般卡尔曼滤波中因模型确定误差和动态目标突然加速而导致的滤波发散现象,如果增加约束条件的约束力较小时,同样会出现滤波结果偏离,因此,带约束条件的滤波同样需要考虑滤波的自适应性.     

SINS的SRC-KF姿态估计算法

基于飞行器载体SINS姿态计算精度要求,提出了一种SINS(strap-down inertial navigation system)的球面径向容积卡尔曼(spherical-radial cubature Kalman filtering, SRC-KF) 姿态确定算法。该算法把笛卡尔坐标系中状态向量变换到球坐标系中,通过Gauss-Hermite求积计算获得2n个球面径向容积点及其权值系数来逼近计算系统状态估计及其方差矩阵,其计算精度可达到三阶;采用四元数姿态建模方法构建新型SINS状态变量与噪声向量相关的姿态方程模型,利用伪观测向量构建观测噪声与四元数相关的观测方程模型,设计系统噪声方差分离计算算法进行系统噪声方差计算,引入拉格朗日乘子算法计算四元数估计均值,最后利用SINS/CCD姿态估计仿真系统开展的SINS 的SRC-KF姿态模型算法进行仿真验证。通过与中心差滤波(CDKF)和无迹卡尔曼滤波(UKF)算法计算结果进行对比,可以看出SRC-KF算法具有计算精度高以及数值计算稳定等特点。

     

On non-linear low–low SST observation equations for the determination of the geopotential based on an analytical solution

In satellite data analysis, one big advantage of analytical orbit integration, which cannot be overestimated, is missed in the numerical integration approach: spectral analysis or the lumped coefficient concept may be used not only to design efficient algorithms but overall for much better insight into the force-field determination problem. The lumped coefficient concept, considered from a practical point of view, consists of the separation of the observation equation matrix A=BT into the product of two matrices. The matrix T is a very sparse matrix separating into small block-diagonal matrices connecting the harmonic coefficients with the lumped coefficients. The lumped coefficients are nothing other than the amplitudes of trigonometric functions depending on three angular orbital variables; therefore, the matrix N=B ^T B will become for a sufficient length of a data set a diagonal dominant matrix, in the case of an unlimited data string length a strictly diagonal one. Using an analytical solution of high order, the non-linear observation equations for low–low SST range data can be transformed into a form to allow the application of the lumped concept. They are presented here for a second-order solution together with an outline of how to proceed with data analysis in the spectral domain in such a case. The dynamic model presented here provides not only a practical algorithm for the parameter determination but also a simple method for an investigation of some fundamental questions, such as the determination of the range of the subset of geopotential coefficients which can be properly determined by means of SST techniques or the definition of an optimal orbital configuration for particular SST missions. Numerical results have already been obtained and will be published elsewhere. Received: 15 January 1999 / Accepted: 30 November 1999     

Upstream control of river anastomosis by sediment overloading,upper Columbia River,British Columbia,Canada

Anastomosing rivers, systems of multiple interconnected channels that enclose floodbasins, constitute a major category of rivers for which various sedimentary facies models have been developed. While the sedimentary products of anastomosing rivers are relatively well‐known, their genesis is still debated. A rapidly growing number of ancient alluvial successions being interpreted as of anastomosing river origin, including important hydrocarbon reservoirs, urge the development of robust models for the genesis of anastomosis, to facilitate better interpretation of ancient depositional settings and controls. The upper Columbia River, British Columbia, Canada, is the most‐studied anastomosing river and has played a key role in the development of an anastomosing river facies model. Two hypotheses for the origin of upper Columbia River anastomosis include the following: (i) downstream control by aggrading cross‐valley alluvial fans; and (ii) upstream control by excessive bedload input from tributaries. Both upstream and downstream control may force aggradation and avulsions in the upper Columbia River. In order to test both hypotheses, long‐term (millennia‐scale) floodplain sedimentation rates and avulsion frequencies are calculated using ¹⁴C‐dated deeply buried organic floodplain material from cross‐valley borehole transects. The results indicate a downstream decrease in floodplain sedimentation rate and avulsion frequency along the anastomosed reach, which is consistent with dominant upstream control by sediment overloading. The data here link recent avulsion activity to increased sediment supply during the Little Ice Age (ca 1100 to 1950 ad ). This link is supported by data showing that sediment supply to the upper Columbia study reach fluctuated in response to Holocene glacial advances and retreats in the hinterland. Upstream control of anastomosis has considerable implications for the reconstruction of the setting of interpreted ancient anastomosing systems. The present research underscores that anastomosing systems typically occur in relatively proximal settings with abundant sediment supplied to low‐gradient floodplains, a situation commonly found in intermontane and foreland basins.     

石墨衬瓷皿在硫酸钡分析中的应用

用石墨衬瓷皿替代铂坩埚,碱熔分解硫酸钡矿样,熔样条件为750℃,保温20min。该分析方法成本低,分析结果稳定、可靠。适用于中小型矿山生产过程中硫酸钡的测定。     

钻孔应变台站记震能力研究

以昌平台体应变为例,研究了体现钻孔应变台站记震能力的方法,并对计算步骤和处理方法进行了说明.选取20套中国大陆观测时间较长且数据较好的钻孔体应变仪观测记录作为研究对象,计算出其各自的记震能力线,给出各台对6级地震的响应范围.此公式不仅可以量化钻孔应变仪的对地震的反应能力,而且是对地震仪器的一种新的科学评估方法.同时,基于地震前兆释放能量小于地震发生时释放的能量的基本理解,此结果对于确定地震前兆的位置和震级范围也有参考价值.     

Macro‐and Microstructural,Textural Fabrics and Deformation Mechanism of Calcite Mylonites from Xar Moron‐Changchun Dextral Shear Zone,Northeast China

The calcite mylonites in the Xar Moron-Changchun shear zone show a significance dextral shearing characteristics. The asymmetric(σ-structure) calcite/quartz grains or aggregates, asymmetry of calcite c-axes fabric diagrams and the oblique foliation of recrystallized calcite grains correspond to a top-to-E shearing. Mineral deformation behaviors, twin morphology, C-axis EBSD fabrics, and quartz grain size-frequency diagrams demonstrate that the ductile shear zone was developed under conditions of greenschist facies, with the range of deformation temperatures from 200 to 300°C. These subgrains of host grains and surrounding recrystallized grains, strong undulose extinction, and slightly curved grain boundaries are probably results of intracrystalline deformation and dynamic recrystallization implying that the deformation took place within the dislocation-creep regime at shallow crustal levels. The calculated paleo-strain rates are between 10~(–7.87)s~(–1) and 10~(–11.49)s~(–1) with differential stresses of 32.63–63.94 MPa lying at the higher bound of typical strain rates in shear zones at crustal levels, and may indicate a relatively rapid deformation. The S-L-calcite tectonites have undergone a component of uplift which led to subhorizontal lifting in an already non-coaxial compressional deformation regime with a bulk pure shear-dominated general shear. This E-W large-scale dextral strike-slip movement is a consequence of the eastward extrusion of the Xing'an-Mongolian Orogenic Belt, and results from far-field forces associated with Late Triassic convergence domains after the final closure of the Paleo-Asian Ocean.     

遥感大数据条件下多星一体化处理与分析

中国对地观测数据获取量持续增加,已步入遥感大数据时代,开展多星一体化数据处理与应用已成为发展趋势。文章从成像处理与信息提取两个方面系统回顾了技术发展过程,剖析了现有前沿方法的优势和特点,指出成像处理领域建立统一处理模型、信息提取领域建立高效学习模型面临的主要挑战。在此基础上,结合实际应用需求,提出了遥感大数据条件下多星一体化处理与分析的新思路,重点阐述了多星一体化处理与分析的基本概念、科学问题与解决方案,通过构建基于生成对抗网络的多星一体化成像处理模型与记忆保持的多任务特征共享与小样本增量学习模型,综合利用不同卫星和载荷间、不同任务和目标间信息,实现高质量图像产品的生成与高精度标注结果的提取。文末给出了技术途径和初步试验验证,并展望后续技术攻关方向。     

Rhenium‐Osmium Isotope Measurements of Geological Reference Material BIR‐1a: Evaluation of Homogeneity and Implications for Method Validation and Quality Control

To evaluate the homogeneity of geological reference material BIR‐1a (basalt; United States Geological Survey, USGS) for Re‐Os isotopic studies at the 0.2–1.0 g test portion size level, sixty‐three precise measurement results of Re and Os mass fractions and isotope amount ratios were obtained over an 18‐month period. These data reveal that the reference material has higher Re (0.691 ± 0.022 ng g^?1, 2s, n = 63) and lower Os mass fractions (0.343 ± 0.089 ng g^?1, 2s, n = 63) than UB‐N (serpentinite, CRPG) and is homogeneous in ¹⁸⁷Os/¹⁸⁸Os isotope amount ratio (0.13371 ± 0.00092, 2s, n = 63) at the 0.2–1.0 g test portion size level. The results are essentially consistent with previous views indicating that BIR‐1a gives precise measurement results for Re‐Os isotope amount ratio measurements at the 1 g test portion size level (Ishikawa et al., Chemical Geology, 2014, 384, 27–46; Meisel and Horan, Reviews in Mineralogy and Geochemistry, 2016, 81, 89–106). Based on these new Re‐Os data and previous studies, we propose BIR‐1a as a useful reference material that can be used in method validation and quality control and interlaboratory comparisons for studies dealing with mafic geological samples at test portion sizes of > 0.4 g.     

萤石重晶石方解石共生非金属矿物分析方法研究

萤石、方解石、重晶石是自然界中普遍共生的非金属矿,具有十分重要的经济价值.目前对于该类共生矿物中不同矿物含量的分离测定,尚未建立较系统、准确的方法.本文通过条件试验,选用10％冰醋酸作为溶剂溶解分离方解石和萤石,硝酸-高氯酸溶解分离萤石和重晶石,制定了一套适用于方解石、萤石、重晶石共生矿物的分离分析方法流程.应用该实验流程对三类矿石组合样品及实际样品进行分析,内外检的测定结果准确可靠;对GBW 07250 ～ GBW 07254五个萤石国家一级标准物质和一个重晶石管理样品进行分析,方法精密度(RSD)＜0.4％,证明该方法流程也适用于萤石或重晶石含量较高的样品分析.与国家标准方法GB/T 5195.1-2006(萤石氟化钙含量测定)比较,本流程更加连续简便,可指导方解石、萤石、重晶石共生矿物资源评价、选矿及回收试验,有利于提高该类非金属矿物的综合利用价值.