判断观测值粗差能否发现和定位的一种验前方法   总被引：5，自引：2，他引：5  

岑敏仪  卓健成  李志林  丁晓利 《测绘学报》2003,32(2):134-138

由于最小二乘(LS)残差统计相关，使得粗差发现和定位关系变得相当复杂，且至今未见有效的理论和方法。作者依据在LS平差前进行粗差发现和定位的思路，有意避开LS残差统计相关的难题，从条件平差模型推导出粗差判断方程(GEJE)Vr＝JVt Wc建立起以上式判断矩阵J为基础的粗差发现和定位的判断准则：1．不能发现含有粗差的观测量；2．能发现含有粗差但不能定位粗差的观测量。通过算例的检验，证明了判断矩阵J与控制网中观测量数据结构的对应关系，同时说明粗差不能定位的观测量，再好的粗差检测方法也无法正确定位粗差。  相似文献   

Taxonomy, facies relationships and palaeobiology of bakevelliid bivalves from the Lower Cretaceous of west-central Argentina     

Darío Gustavo Lazo   《Cretaceous Research》2003,24(6):765

Cretaceous bakevelliids in Argentina are restricted to the Lower Cretaceous. They are recorded in shallow marine deposits in two Mesozoic basins located in the Andes foothills in Patagonia. In the Austral Basin (44°–55°S) there is only one genus, Gervillella, represented by a single specimen from the Barremian. In the Neuquén Basin (30°–40°S) two genera, Gervillaria and Gervillella, occur, ranging from the Berriasian to the Lower Barremian. In the Pilmatué Member of the Agrio Formation two species are identified: Gervillaria alatior (Imlay) and Gervillella aviculoides (J. Sowerby). The former is also recorded in Mexico while the latter is more widespread, occurring in Europe, Asia, and Africa. In the Bajada del Agrio section they come from eight tabular shell beds located near and on top of shallowing-upwards cycles. They were abundant only in four of these levels. These shell beds are interpreted as having been deposited in the mid-ramp (middle of cycles), and upper mid-ramp (top of cycles). A functional analysis of shells revealed two life habits: epibyssate and endobyssate.  相似文献   

一类计算性系统误差消除与斜压原始方程天气气候模式改进   总被引：1，自引：0，他引：1  

Zhong Qing  Chen Jiatian  Sun Zuoling 《大气科学进展》2002,19(6):1103-1112

斜压原始方程半隐式全能量守恒格式的构造问题长期没有解决。本研究在成功地构造实现其全能量完全守恒的半隐式方案基础上，进行了此守恒方案与欧洲中期天气预报中心（ECMWF）的σ－坐标原始方程全球谱模式半隐式方案间的实际资料对比实验。实验表明，850hPa平均预报高度场RMS误差在积分一周以后得到明显改进，到第30天其预报误差降低达到了50％，进一步的对比实验表明，对流层中部和下部的月预报平均高度场RMS误差也显降低，而且一些明显的系统性误差也得到大幅度改进。更加详细的分析显示，这些收益的很大一部分是从超长波成分的改进中得到的。这说明，通过构造守恒性时间差分方案消除了响应的计算性系统误差源汇，进而能够使模式气候漂移得到显改进，而这种误差源汇存在于传统的，现仍被普遍采用的斜压原始方程天气气候模式中。  相似文献   

Late Cretaceous plants from the Bonarelli Level of the Venetian Alps, northeastern Italy     

Bernard Gomez  Frdric Thvenard  Marco Fantin  Luca Giusberti 《Cretaceous Research》2002,23(6):671

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河南省连康山光萼苔科植物区系地理成分研究     

赵建成  崔彦伟  叶永忠  袁志良 《地理与地理信息科学》2002,18(4):107-110

该文在研究标本和文献的基础上,介绍河南省连康山自然保护区所产的光萼苔科(Porellaceae)植物2属8种,即光萼苔属Porella(7种)和多瓣苔属Macvicaria(1种)。讨论了它们的生境、识别特征和植物区系地理成分,并编制了河南省连康山自然保护区光萼苔科植物的分属、分种检索表。  相似文献   

Anisian ammonoids from Qingyan, southwestern China: biostratigraphical implications for the age of the Qingyan Formation     

Frank Stiller  Hugo Bucher 《Swiss Journal of Geoscience》2008,101(2):547-562

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Cyclocrinus, an enigmatic Jurassic–Cretaceous crinoid     

Hans Hess 《Swiss Journal of Geoscience》2008,101(2):465-481

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基于多参考站网络的VRS算法研究与实现     

ZHANG Feng  HAO Jin-ming  CHONG Dian-wei  LIANG Shuai 《测绘学院学报》2008,(6)

多参考站网络的建立,为网络RTK的实现奠定了基础。虚拟参考站技术是网络RTK的一种,它以众多的优势代表了网络RTK的主要发展趋势。简单介绍了VRS系统的工作原理;从基准站间双差改正数的生成、虚拟观测值的生成和流动站处的定位解算3个方面,详细推导了VRS的数学模型;针对差分改正信息,提出了综合误差内插算法;最后,利用4个已知点的观测数据,结合编程计算,证明了文中VRS数学模型的正确性,为虚拟参考站系统的进一步研究提供依据。  相似文献   

Directional errors in remanent magnetization of non-cubic soft sediment specimens measured with spinner magnetometers     

William K. Steele 《Geophysical Journal International》1989,96(2):333-341

Summary. This paper assesses theoretically and experimentally the errors in palaeomagnetic directions introduced by measuring rectangular but non-cubic blocks of soft sediments in slow speed spinner magnetometers. Plastic boxes commonly used for this purpose hold samples 21 × 21 × 15 mm. This study models the response of Schonstedt and Molspin spinners to such specimens and presents the results of experiments in which the remanent magnetization (RM) of obsidian blocks, both as cubes and after subsequent cutting to fit within the boxes, was measured to determine actual instrument behaviour. These experiments indicate that the error introduced by use of specimens of the above dimensions may be as much as 8.5° for the smallest specimen-sensor separation in the Schonstedt spinner. For the Molspin spinner and for the next smallest specimen-sensor separation in the Schonstedt instrument, the error is smaller but nevertheless non-negligible.  相似文献   

Contribution of ionospheric irregularities to the error of dual-frequency GNSS positioning     

B. C. Kim  M. V. Tinin 《Journal of Geodesy》2007,81(3):189-199

This paper investigates the third-order residual range error in the dual-frequency correction of ionospheric effects on satellite navigation. We solve the two-point trajectory problem using the perturbation method to derive second-approximation formulas for the phase path of the wave propagating through an inhomogeneous ionosphere. It is shown that these formulas are consistent with the results derived from applying perturbation theory directly to the eikonal equation. The resulting expression for the phase path is used in calculating the residual range error of dual-frequency global positioning system (GPS) observations, in view of second- and third-order terms. The third-order correction includes not only the quadratic correction of the refractive index but also the correction for ray bending in an inhomogeneous ionosphere. Our calculations took into consideration that the ionosphere has regular large-scale irregularities, as well as smaller-scale random irregularities. Numerical examples show that geomagnetic field effects, which constitute a second-order correction, typically exceed the effects of the quadratic correction and the regular ionospheric inhomogeneity. The contribution from random irregularities can compare with or exceed that made by the second-order correction. Therefore, random ionospheric irregularities can make a significant (sometimes dominant) contribution to the residual range error.  相似文献