排序方式: 共有14条查询结果,搜索用时 15 毫秒
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Paul R. Mahaffy Mehdi Benna Todd King Daniel N. Harpold Robert Arvey Michael Barciniak Mirl Bendt Daniel Carrigan Therese Errigo Vincent Holmes Christopher S. Johnson James Kellogg Patrick Kimvilakani Matthew Lefavor Jerome Hengemihle Ferzan Jaeger Eric Lyness John Maurer Anthony Melak Felix Noreiga Marvin Noriega Kiran Patel Benito Prats Eric Raaen Florence Tan Edwin Weidner Cynthia Gundersen Steven Battel Bruce P. Block Ken Arnett Ryan Miller Curt Cooper Charles Edmonson J. Thomas Nolan 《Space Science Reviews》2015,196(1-4):49-77
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The technical approach for the development of the computer model of an integrated electro-hydraulic system is presented. As an example, the development of the computer model of the Space Shuttle Electric Auxiliary Power Unit (EAPU) is discussed. The integrated model consists of power source, electric power distribution and control (EPD&C), and mechanical and hydraulic loads. The modeling and analysis results, model interface issues, EPD&C interactions with the power sources, and EPD&C interaction with the electro-hydraulic load are discussed . The selected computer tool facilitates the development of "submodel" corresponding to the subsystem in the integrated system. This modeling approach and the models developed for EAPU can be generalized and adapted for the detailed modeling, simulation, and analysis of other aerospace and commercial electro-mechanical systems 相似文献
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Mehdi Eshagh Mohsen Romeshkani 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The Earth’s gravity field modelling is an ill-posed problem having a sensitive solution to the error of data. Satellite gravity gradiometry (SGG) is a space technique to measure the second-order derivatives of geopotential for modelling this field, but the measurements should be validated prior to use. The existing terrestrial gravity anomalies and Earth gravity models can be used for this purpose. In this paper, the second-order vertical–horizontal (VH) and horizontal–horizontal (HH) derivatives of the extended Stokes formula in the local north-oriented frame are modified using biased, unbiased and optimum types of least-squares modification. These modified integral estimators are used to generate the VH and HH gradients at 250 km level for validation purpose of the SGG data. It is shown that, unlike the integral estimator for generating the second-order radial derivative of geopotential, the system of equations from which the modification parameters are obtained is unstable for all types of modification, with large cap size and high degree, and regularization is strongly required for solving the system. Numerical studies in Fennoscandia show that the SGG data can be estimated with an accuracy of 1 mE using an integral estimator modified by a biased type least-squares modification. In this case an integration cap size of 2.5° and a degree of modification of 100 for integrating 30′ × 30′ gravity anomalies are required. 相似文献