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161.
162.
It is an objective fact that there exists error in the satellite dynamic model and it will be transferred to satellite orbit determination algorithm, forming a part of the connotative model error. Mixed with the systematic error and random error of the measurements, they form the unitive model error and badly restrict the precision of the orbit determination. We deduce in detail the equations of orbit improvement for a system with dynamic model error, construct the parametric model for the explicit part of the model and nonparametric model for the error that can not be explicitly described. We also construct the partially linear orbit determination model, estimate and fit the model error using a two-stage estimation and a kernel function estimation, and finally make the corresponding compensation in the orbit determination. Beginning from the data depth theory, a data depth weight kernel estimator for model error is proposed for the sake of promoting the steadiness of model error estimation. Simulation experiments of SBSS are performed. The results show clearly that the model error is one of the most important effects that will influence the precision of the orbit determination. The kernel function method can effectively estimate the model error, with the window width as a major restrict parameter. A data depth-weight-kernel estimation, however, can improve largely the robustness of the kernel function and therefore improve the precision of orbit determination. 相似文献
163.
Giovanni Federico Gronchi 《Celestial Mechanics and Dynamical Astronomy》2009,103(4):301-326
Charlier’s theory (1910) provides a geometric interpretation of the occurrence of multiple solutions in Laplace’s method of
preliminary orbit determination, assuming geocentric observations. We introduce a generalization of this theory allowing to
take into account topocentric observations, that is observations made from the surface of the rotating Earth. The generalized
theory works for both Laplace’s and Gauss’ methods. We also provide a geometric definition of a curve that generalizes Charlier’s
limiting curve, separating regions with a different number of solutions. The results are generically different from Charlier’s:
they may change according to the value of a parameter that depends on the observations. 相似文献
164.
微波消解等离子体发射光谱和石墨炉原子吸收光谱法联合测定土壤中多元素 总被引:6,自引:2,他引:4
采用密闭式微波消解系统处理土壤样品,电感耦合等离子体发射光谱法或石墨炉原子吸收光谱法测定土壤样品中铜、砷、铅、锌、钴、铬、锰、镍、钒9个元素。分别从消解液的选择、用酸量及样品消解量等方面进行消解条件的优化,确定了一个最适合土壤消解的前处理体系。各元素的检出限为0.16~2.52μg/g,回收率为95.2%~106.6%,精密度为2.03%~9.79%(n=7)。方法简单快速,效率高,劳动强度低,是进行土壤中多元素测定的高效方法。 相似文献
165.
166.
D. Ask O. Stephansson F. H. Cornet M. V. S. Ask 《Rock Mechanics and Rock Engineering》2009,42(4):559-584
The primary objectives of this work are to (1) improve the understanding of the prevailing stress distribution at the Äspö Hard Rock Laboratory (HRL) in SE Sweden by employing an integrated stress determination approach, and in order to accomplish this (2) extend the existing stress integration methodology denominated integrated stress determination method (ISDM; Cornet in Comprehensive Rock Engineering vol 3, Pergamon Press, Oxford, pp 413–432, 1993a). The new developments of the ISDM involve a 12-parameter representation of the regional stress field in the rock mass (i.e., the full stress tensor and its variation with depth) that is applicable to hydraulic stress data (sleeve fracturing, hydraulic fracturing, and hydraulic tests on pre-existing fractures), overcoring data (CSIR- and CSIRO-type of devices), and to combinations of hydraulic and overcoring stress data. For the latter case, the elastic parameters of the overcoring technique may be solved in situ by allowing the hydraulic stress data to constrain them. As a result, the problem then involves 14 model parameters. Results from the study show that the ISDM effectively improves the precision of the prevailing stress field determination and that it is especially powerful for identification of consistencies/inconsistencies in an existing data set. Indeed, this is the very basic premise and goal of stress integration; combine all available data to achieve as complete a characterization of the mechanical stress model as possible, and not to identify a solution that fits only loosely the maximum amount of stress data. 相似文献
167.
168.
???÷?????????????ü??????????????????????????GEMT3??JGM3??EGM96??TEG4??EIGEN2??EIGEN??GL04C??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????н???????????CHAMP ??GRACE?????????????????????????????????????????????????????????????????cm????????22.47 cm????????????к??????? 相似文献
169.
堆浸生产中高锑样品金的测定 总被引:3,自引:0,他引:3
堆浸提金生产中,高锑样品的湿法测金,用氯化铵和溴化氢挥发法除去锑对金测定的干扰,用氢醌容量法测定,快速、简单,效果明显。 相似文献
170.
V. A. Sarychev S. A. Mirer A. A. Degtyarev 《Celestial Mechanics and Dynamical Astronomy》2008,100(4):301-318
Attitude motion of a satellite subjected to gravitational and aerodynamic torques in a circular orbit is considered. In special
case, when the center of pressure of aerodynamic forces is located in one of the principal central planes of inertia of the
satellite, all equilibrium orientations are determined. Existence conditions of all equilibria are obtained and evolution
of domains with a fixed number of equilibria is investigated in detail. All bifurcation values of the system’s parameters
corresponding to the qualitative change of these domains are determined. Sufficient conditions of stability are obtained for
each equilibrium orientation using generalized integral of energy. 相似文献