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论高精度GPS高程测量 总被引：3，自引：0，他引：3
本文分析了ＧＰＳ高程系统与我国现行高程系统的区别与联系，介绍了由ＧＰＳ大地高转换为正常高的方法及当前ＧＰＳ高程测量的现状，并提出了提高ＧＰＳ高程测量精度的若干措施，对今后我国高精度ＧＰＳ高程测量工作有一定的指导意义。 相似文献
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讨论ＧＰＳ网的平面坐标和高程位置的转换问题，介绍适用于工程测量应用的简单实用的平面坐标转换模型，还阐述了ＧＰＳ网高程系统变换的方法，最后介绍美国ＤＭＡ的应用实例。 相似文献
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本文简述了ＧＰＳ高程测量与传统高程测量的关系,讨论了几种常用的ＧＰＳ高程拟合方法及其在实践中的应用。 相似文献
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GPS水准高程拟合精度的探讨 总被引：2，自引：0，他引：2
本文根据ＧＰＳ定位技术,在四等ＧＰＳ控制网测量中作了ＧＰＳ水准高程试验,对高程拟合起算点的数量,精度,位置以及整体和分区拟合所获得的各种拟合精度进行了分析和探讨,得出了有益的结论。 相似文献
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利用GPS单点定位数据求解高程的新方法 总被引：1，自引：0，他引：1
全球定位系统可用于测定很精确的三维（水平位置和高程）大地坐标，但其中第三个坐标不能用在测量工程方面，因为这是ＧＰＳ参考系的量，而用水准测量测定的高程是相对于大地水准面的量。为了将ＧＰＳ用于精密高程传递，必需将ＧＰＳ高差转换为正高高差，本文提出两种确定大地水准面倾斜的新方法以及对一个隧洞控制网求出的结果。 相似文献
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《International Journal of Digital Earth》2013,6(1):80-87
Abstract Cultures throughout the world are associating with the rivers. People depend upon the rivers and their tributaries for food, water, transport, and many other aspects of their daily lives. Unfortunately, human beings have not calculated the accurate lengths for the great rivers even today. The lengths of the rivers are very different in popular textbooks, magazines, atlases and encyclopedias, etc. To accurately determine the lengths of the principal rivers of the world, the combination of satellite image analysis and field investigations to the source regions is proposed in this paper. The lengths of the Nile, Amazon, Yangtze, Mississippi, Yellow, Ob, Yenisey, Amur, Congo and Mekong, with lengths over or close to 5000 km, were calculated using the proposed method. The results may represent the most reliable and accurate lengths of the principal rivers of the world that are currently achievable. 相似文献
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软科学这一术语是70年代在国外提出的.然而30多年以来,它在国外不仅未得到普遍的承认,而且对软科学的定义也还未能达成大体上一致的共识.而在改革开放后的中国,出于决策科学化和民主化的需要,经过一些领导人的提倡和支持,特别是通过1986年召开的软科学座谈会及1994年召开的全国软科学工作会议,软科学事业得到了蓬勃的发展.据初步统计,截止1998年底全国共有软科学研究机构1224个,研究人员32655人,初步形成了一支较为强大的研究队伍,并取得了数百项覆盖多个领域的研究成果,为支持各级各类的决策发挥了一定的作用. 相似文献
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Tobias Nilsson Benedikt Soja Kyriakos Balidakis Maria Karbon Robert Heinkelmann Zhiguo Deng Harald Schuh 《Journal of Geodesy》2017,91(7):857-866
The very long baseline interferometry (VLBI) Intensive sessions are typically 1-h and single-baseline VLBI sessions, specifically designed to yield low-latency estimates of UT1-UTC. In this work, we investigate what accuracy is obtained from these sessions and how it can be improved. In particular, we study the modeling of the troposphere in the data analysis. The impact of including external information on the zenith wet delays (ZWD) and tropospheric gradients from GPS or numerical weather prediction models is studied. Additionally, we test estimating tropospheric gradients in the data analysis, which is normally not done. To evaluate the results, we compared the UT1-UTC values from the Intensives to those from simultaneous 24-h VLBI session. Furthermore, we calculated length of day (LOD) estimates using the UT1-UTC values from consecutive Intensives and compared these to the LOD estimated by GPS. We find that there is not much benefit in using external ZWD; however, including external information on the gradients improves the agreement with the reference data. If gradients are estimated in the data analysis, and appropriate constraints are applied, the WRMS difference w.r.t. UT1-UTC from 24-h sessions is reduced by 5% and the WRMS difference w.r.t. the LOD from GPS by up to 12%. The best agreement between Intensives and the reference time series is obtained when using both external gradients from GPS and additionally estimating gradients in the data analysis. 相似文献
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In this letter, we are trying to resolve the electromagnetic problem for the movements of the superconducting particles of the protoplanetary cloud in the magnetic field of Saturn. The force of levitation (Meissner-Ochsenfeld phenomenon) is introduced to the field of planetary science for the first time. It is shown from our theoretical analysis that rings of Saturn might have a superconducting origin, and rings might levitate within magnetic equator plane of the planet. 相似文献
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跟踪世界发展动态 致力地球重力场研究 总被引：12，自引：6，他引：12
宁津生 《武汉大学学报(信息科学版)》2001,26(6):471-475
比较系统、扼要地叙述了笔者所在单位40余年来坚持跟踪世界发展动态，致力于地球重力场理论和方法的研究，并从教学和生产需要出发，在地球重力场研究方面所获得的一些有理论意义和实用价值的成果。 相似文献