检索结果-南通市图书馆

CHINA: MAIN GEODETIC ACTIONS 1996-2.00

在线全文

cnki会议

学校读者我要写书评

暂无评论

Bulletin of the chinese academy of Sciences 1996年第4期10卷 286-290页

作者： Chen Junyong(National Bureau of surveying and map.ing, {2.) CAS Member

This article reviews the progress made in geodetic work in China since the *** order to meet the needs of China’s economic and defense construction,and scientific and social development in the early 2.th century,some main geodetic actions which should be completed before 2.00 are proposed as follows.(1) Monitoring vertical crustal movements and conducting studies on its *** of the second phase of the national first order leveling *** of the vertical crustal movement.(2. Improvement of national space geodetic *** main task is to lay down a national B-order GPS network and complete its data processing.(3) Refining of chinese local gravity field on land and *** determination of chinese local quasi geoid with higher than one meter *** of

关键词： GPS data VLBI MAIN GEODETIC ACTIONS 1996-2.00 CHINA

Preliminary Analysis on Pseudorange Data Quality and Positioning Accuracy of Beidou Satellite Navigation System

在线全文

学校读者我要写书评

暂无评论

Preliminary Analysis on Pseudorange Data Quality and Positio...

第三届中国卫星导航学术年会

作者： Liang Chen 1,2.,Qile Zhao 1,Zhigang Hu1,Ying Zhao3,Feng Xiang 1 1 GNSS Research Center,Wuhan University,12. Luoyu Road,Wuhan 4.0079,China 2.Satellite Navigation System Engineering Center,China {2. of Aerospace Electronics Technology,1 Fengyingdong Road,beijing 100094.China 3 chinese {2. of {4. and map.ing,National Administration of {4.,map.ing and Geo-information,2. Lianhuachixi Road,beijing 100830,China

There are 7 valid satellites in Beidou navigation system（COMPASS） now,including 3 Geostationary Orbit satellites（GEO）and 4.inclined Geo-synchronization orbit satellites（IGSO）.In this paper,assessment methods of COMPASS satellite pseudorange observation’s accuracy are researched into and COMPASS data are analyzed with self-compiled software in *** pseudo-range point positioning accuracy was also analyzed with the software and COMPASS data collected from September 5 to 11,2.11,and data quality control methods are studied during this *** results demonstrate that:COMPASS pseudorange’s multi-path effects and measurement errors are about 0.5 meter to 3 meters;The percentage of coordinate differences-△N-、-△E-、-△U-within less than 10 meters in pseudorange single point positioning（October 2.are 67%、100% and 64.,respectively;the accuracy（RMS）in the North,East and Up direc-tion during these seven days are about 9.70 meters、5.56 meters、11.2. meters;The horizontal and three dimensional positioning accuracies are about 11.2. and 15.92.meters respectively.

关键词： COMPASS pseudorange observation pseudorange single point positioning accuracy analysis

Application of Inter-system Hardware Delay Bias in GPS/GLONASS PPP

在线全文

cnki会议

学校读者我要写书评

暂无评论

Application of Inter-system Hardware Delay Bias in GPS/GLONA...

第三届中国卫星导航学术年会

作者： Xiao Pei1, 2. Junping Chen2., Jiexian Wang1, 3, Yize Zhang1, 2. Haojun Li2. Department of surveying and Geo-informatics, Tongji University2.Shanghai Astronomical Observatory (SHAO), {2. academy of Sciences (CAS)3 Key Lab of Advanced surveying Engineering of SBSM

GPS applies Code Division Multiple Access technique in signal coding,while GLONASS’s signal is produced with Frequency Division Multiple Access technique. The differences in signal frequency results in inter-system hardware delay bias for GPS/GLONASS receivers. Subjecting to these hardware delays,strategies and models of GPS/GLONASS PPP based positioning needs to be modified. We derived a GPS/GLONASS combined PPP positioning models by introducing inter-system hardware delay biases. Several scenarios were simulated to test the introduced models using the observation of IGS stations. The results show that: ① Adding a couple of GLONASS satellites can improve the positioning accuracy in the environment without enough GPS satellites being tracked;②The inter-system hardware delay bias is stable on daily base, and it could be predicted and be fixed in the GPS/GLONASS combined PPP.

关键词： GPS GLONASS Precise Point Positioning positioning accuracy hardware delay

在线全文

cnki会议

学校读者我要写书评

暂无评论

LUCC信息的智能化提取

山东农业大学学报（自然科学版） 2003年第3期34卷 406-409页

作者：王萍李玉环郑永果张继贤林宗坚山东科技大学山东泰安271019 中国测绘科学研究院

笔者利用ETM +、TM及部分SPOT影像 ,通过对上海奉贤区进行LUCC(2.0 0 0年 - 1998年 )变化信息提取 ,针对研究区 ,提取并发展了两到三种实用且效果明显的处理方法 :如差值阈值法用于变化图斑发现 ,多时相假彩色合成影像用于分层提取变化... 详细信息

笔者利用ETM +、TM及部分SPOT影像 ,通过对上海奉贤区进行LUCC(2.0 0 0年 - 1998年 )变化信息提取 ,针对研究区 ,提取并发展了两到三种实用且效果明显的处理方法 :如差值阈值法用于变化图斑发现 ,多时相假彩色合成影像用于分层提取变化类型的方法等 ,在ERDAS实现了人工干预下的计算机智能提取 ,经野外检查 ,试验结果理想。

关键词： LUCC信息智能化提取多时相假彩色合成差值阈值法信息提取

Relativistic Effects in Space Geodesy

在线全文

学校读者我要写书评

暂无评论

Relativistic Effects in Space Geodesy

作者： HUANG Cheng Ding Xiaoli CHEN Yongqi 1 Shanghai Astronomical Observatory, chinese {2. of Sciences, Shanghai 2.0030 2.Dept. of Land surveying and Geo-Informatics, Hong Kong Polytechnic University, Hong Kong

Space Geodesy involves the measurement or monitoring of variation of spatial motion of the Earth as a whole and mass motion of each layer of the Earth, using space - based techniques. They concern the space and time, which belong to the realm of General Relativity. With the rapid increase of space - based observational accuracy, the relativistic effects in Space Geodesy must be taken into account to make full use of the information of high precise observation. This paper will review the principal relativistic effects in Space Geodesy briefly.

关键词：

Design,construction and mechanical behavior of relics of complete large Longyou rock caverns carved in argillaceous siltstone ground

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2011年第2期3卷 131-152页

作者： Zhifa Yang1, Zhongqi Yue2. Lihui Li1 1 Key Laboratory of Engineering Geomechanics, Institute of Geology and Geophysics, chinese {2. of Sciences, {4., 10002., China 2.Department of Civil Engineering, the University of Hong Kong, Hong Kong, China Key Laboratory of Engineering Geomechanics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Department of Civil Engineering the University of Hong Kong Hong Kong China

This paper presents a comprehensive summary of data, analyses and findings from the investigations over the past twelve years about the relics of large Longyou rock caverns carved about 2.000 years ago at shallow depths in argillaceous siltstone. The paper presents the typical features associated with the rock caverns. They include structures, large spans, portals, extreme shallow-buried depths, imprints, drainages, inclined ceiling, inclined sidewalls, slender rock pillars, rock staircases, site and strata selections, caving lighting, carving method, and underground construction surveying. They are used to reconstruct and highlight the design and construction methods adopted by the ancients. The paper further demonstrates that the relics of the complete large rock caverns are a consequence of coincidental combinations of ancient human effort and natural factors. The full occupation of water with weak acidity in the large rock caverns with the soft surrounding rocks of weak alkalinity is found to be the main factor ensuring and preserving the caverns to have been stable and integral over 2.000 years. However, the five unwatered complete rock cavern relics have been experiencing various deteriorations and small failures including cracks, seepage, small rock falls and delaminating ceiling rocks. Although these deteriorations have been repaired and stabilized effectively, the paper demonstrates that an entire roof collapse failure is highly possible in the near future to each of the five unwatered rock cavern relics. The findings presented in this paper are also invaluable both to the long-term protection and preservation of the large rock cavern relics of national and international interests and importance, and to extend and enrich our experience and knowledge on the long-term stability and integrity of man-made underground rock cavern engineering projects.

关键词： rock cavern rock mechanics rock engineering long-term stability and integrity argillaceous siltstone environment

Unified representation of gravitation field in consideration of effect of ellipsoid flattening

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1997年第19期42卷 1631-1636页

作者： ZHU ZhuowenLaboratory for Modern Geodynamics, Wuhan Technical University of surveying and map.ing, Wuhan 4.0079, China Laboratory for Modern Geodynamics Wuhan Technical University of Surveying and Mapping Wuhan China

THE theory of unified representation of gravitation field proposed by the author is modelledupon spherical approximation for disturbing potential. It is a common knowledge that sphericalapproximation should lead to a result involving an innate error. This kind of error is tolerableonly for general application, an ellipsoidal correction has to be taken into account in case of de-siring for a result with higher accuracy. The purpose of this note is to try to make an

关键词： unified representation of gravitation field interior Dirichlet’ s problem of biharmonic equation for ellipsoidal domain radial shrinking map.ing approximation problem anomalous density.

在线全文

学校读者我要写书评

暂无评论

相对论框架中的时间计量

天文学进展 2002年第2期20卷 107-113页

作者：韩春好中国科学院测量与地球物理研究所

介绍了原时、坐标时等相对论框架中时间计量的基本概念,讨论了时间尺度的基本定义与实现,如地球时(TT)、国际原子时(TAI)、时钟调整和时间比对等。

关键词：相对论时间尺度时间比对地球时国际原子时时钟调整

A survey of next generation mobile communications researchin China

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2011年第5期56卷 2875-2888页

作者： TIAN JinFeng 1,2., ZHENG XiaoYing 2.3 , HU HongLin 1,2.YOU XiaoHu 1,3 1 Shanghai Research Center for Wireless Communications (WiCO), Shanghai 2.0335, China 2.Shanghai Institute of Microsystem and Information Technology (SIMIT), chinese {2. of Sciences (CAS), Shanghai 2.0050, China 3 National Mobile Communications Research Laboratory, Southeast University (SEU), Nanjing 2.0096, China Shanghai Research Center for Wireless Communications (WiCO) Shanghai Institute of Microsystem and Information Technology (SIMIT) Chinese Academy of Sciences (CAS) National Mobile Communications Research Laboratory Southeast University (SEU)

With the rapid development of wireless communication networks, the fourth generation (4.) has emerged to move beyond the limitations of the third generation (3G), with increased bandwidth, enhanced quality of services, and reduced costs of resources. In this paper, we discuss the key technologies of 4. and focus on surveying the ongoing research in 4. communications in China. The 4. technologies under investigation include multicarrier transmission, multiple antenna techniques, carrier aggregation, relays, cognitive radio, distributed antenna systems, network convergence, and network self-optimization. These technologies are the building blocks of 4. and contribute largely to the requirements of International Mobile Telecommunications Advanced (IMT-Advanced). For each technology, its benefits, research topics, and some existing approaches are examined. Finally, we briefly discuss the challenges and future research issues in 4. systems.

关键词：下一代移动通信中国无线通信网络分布式天线系统 4.系统多载波传输国际移动通信认知无线电

同方期刊数据库