排序方式： 共有18条查询结果，搜索用时 15 毫秒
1.
Angelika van der Linde 《Mathematical Geology》1993,25(1):1-7
Least squares estimation (LSE) is theoretically related to quadratic unbiased estimation of variance components. It is argued that these methods of estimation of variance components essentially generalize LSE though they are not formally equivalent. 相似文献
2.
本文提出了一种适用于协方差阵奇异或非奇异、设计阵列满秩或降秩时的方差分量估计方法;其公式推导简单,形式统一,不需解线性方程组,同时可保证迭代计算方差分量的非负要求。作为特例还和Helmert法及MINQUE法作了比较。最后讨论了用真误差进行方差分量估计的计算公式,并给出了一个测距误差分析的实例。 相似文献
3.
MINQUE for block diagonal bordered systems such as those encountered in VLBI data analysis 总被引：1，自引：1，他引：0
A sparse matrix method is developed for computing variance factors for block-diagonal, bordered systems of equations using
MINQUE (Minimum Norm Quadratic Unbiased Estimation). This method greatly reduces the computational effort required to apply
MINQUE, thus making it practical to compute variance factors for some very large systems of equations. The computer implementation
of the method is described and applied to the computation of variance factors for a combination of 1609 VLBI (Very Long Baseline
Interferometry) observing sessions. The purpose of this test was to compute a variance factor for each of the data sets and,
perhaps, to obtain more realistic variance estimates to replace those in common use for the analysis of VLBI data. It was
found that the method is satisfactory for use with such large problems, and the test served to verify that the variances in
current use in VLBI data adjustments are adequate.
Received: 26 November 1996 / Accepted: 12 December 1997 相似文献
4.
基于方差分量估计的拟合推估及其在GIS误差纠正的应用 总被引：2，自引：0，他引：2
拟合推估解算必须首先求得信号向量的方差协方差矩阵,该协方差矩阵一般通过选定的协方差函数,并通过已测点数据进行拟合得到。显然观测噪声的先验方差协方差阵与拟合得到的随机信号的方差协方差矩阵必须相互协调,即观测噪声向量和信号向量的权矩阵所对应的方差因子应该一致,否则将对固定效应和随机效应参数的估计带来系统性的影响。应用方差分量估计来协调拟合推估模型中观测噪声和信号向量的随机模型,并分别从极大似然估计、MINQUE估计、赫尔默特方差分量估计三方面构建了拟合推估模型的方差分量解,最后利用新提出的理论与方法,对一幅实际的扫描地形图进行误差纠正,结果表明基于方差分量估计的拟合推估法能够提高扫描地形图的精度。 相似文献
5.
本文应用最小范数二次无偏估计(MINQUE)理论,研究了GPS基线向量网在椭球面上进行三维平差时的方差和协方差分量的估计问题。从理论上提出了方差—协方差模型的选取原则。并从实践中总结出了同时估计基线之长度、方位、高差的固定方差分量和比例方差分量的交替估计方法。通过大量的实例计算和分析,证明这一方法是有效的。 相似文献
6.
综合与归纳了GPS精密定位的三种比较实用的随机模型,提出了将这三种随机模型用于GPS快速精密定位中,通过两个实例分析了三种随机模型对GPS快速精密定位的精度影响,得出几点有益的结论。 相似文献
7.
WANG XinzhouLIU JingnanTAO BenzaoWANG Xinzhou Professor School of Geo-science Surveying Engineering WTUSM Wuhan China 《地球空间信息科学学报》1998,(1)
This paper studies the estimation of variance and covariance compo-nents for GPS baseline network by MINQUE method.The fundamental rule forselecting variance-covariance model has been presented,and the alternative algo-rithm which simultaneouly estimates fixed variance components and scalled vari-ance components of the distance,azimuth and geodetic height difference for a GPSbaseline vector has been developed. 相似文献
8.
Most stochastic modelling techniques neglect the correlations among the raw un-differenced observations when forming the variance–covariance matrix of the Global Navigation Satellite System (GNSS) observations. Some methods were developed to model these correlations. One such method is the Minimum Norm Quadratic Unbiased Estimator (MINQUE). Studies have shown that MINQUE improves ambiguity resolution, and ultimately, the positioning solution in short baselines. However, its effect in cases of processing with longer baselines and on the estimation of zenith wet delay (ZWD) is somewhat unknown. In this paper, a comparison between the impact of neglecting the correlations among the observations using an elevation-angle-dependent model (EADM) and modelling the correlations using MINQUE on height determination and ZWD for medium and long baselines is carried out. The initial testing was carried out across two Australian GNSS stations with a medium-length baseline throughout a three-week campaign. The results showed that using MINQUE did not resolve the coordinate, height and wet delay components as accurately as the EADM. The results were further verified with two long-baseline campaigns whereby EADM was also able to provide better wet delay estimates. The coordinate results were, however, mixed. Overall, the study concluded that the inclusion of the correlations among the observations, in general, do not improve the resolution of the coordinate and wet delay estimates. 相似文献
9.
本文在分析传统CPⅢ平面控制网平差特点的基础上,提出一个新的数学模型,其函数模型为线性模型,随机模型通过最小范数二次无偏估计来确定。利用该数学模型进行平差计算,不需要计算待求参数近似值,不需要迭代计算,因此具有计算工作量小、形式简单等特点。为验证该模型的正确性,编制了程序,模拟观测数据进行平差计算。通过对大量实验数据的分析,证明该模型是可行的。 相似文献
10.