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Improved retracking algorithm for oceanic altimeter waveforms

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Progress in Natural Science:Materials International 2009年第2期19卷 195-203页

作者： Lifeng Bao,Yang Lu,Yong Wang institute of geodesy and geophysics,Chinese Academy of Sciences,wuhan 4.0077,china institute of geodesy and geophysics Chinese Academy of Sciences Wuhan 430077 China

Over the deep oceans without land/ice interference,the waveforms created by the return altimeter pulse generally follow the ocean model of Brown,and the corresponding range can be properly determined using the result from an onboard tracker. In the case of com-plex altimeter waveforms corrupted due to a variety of reasons,the processor on the satellite cannot properly determine the center of the leading edge,and range observations can be in error. As an efficacious method to improve the precision of those altimeter observations with complex waveforms,waveform retracking is required to reprocess the original returning pulse. Based on basic altimeter theory and the geometric feature of altimeter waveforms,we developed a new altimeter waveform retracker,which is valid for all altimeter wave-forms once there exists a reasonable returning signal. The performances of the existing Beta-5 retracker,threshold retracker,improved threshold retracker,and the new retracker are assessed in the experimental regions (china Seas and its adjacent regions),and the improvements in the accuracy of sea surface height are investigated by the difference between retracked altimeter observations and ref-erenced geoid. The comparisons denote that the new algorithm gives the best performance in both the open ocean and coastal regions. Also,the new retracker presents a uniform performance in the whole test region. Besides,there is a significant improvement in the short-wavelength precision and the spatial resolution of sea surface height after retracking process.

关键词： Altimetry Waveform retracking Sea surface height

Determination of vertical gradient of gravity anomaly with topographic data

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Chinese Science Bulletin 1999年第11期44卷 1029-1034页

作者： ZHANG Chijuninstitute of geodesy and geophysics , Chinese Academy of Sciences , wuhan 4.0077 , china institute of geodesy and geophysics Chinese Academy of Sciences Wuhan China

The role of vertical gradient of gravity anomaly in the solution and interpretation of geological and geophysical problems on superficial layer is increasingly evident. However, it is difficult to directly observe the vertical gradient of gravity anomaly in mountainous area. Moreover,aerial and satellite gravity gradient measurments have not been put into practice up to date *** vertical gradient of gravity anomaly is calculated by use of topographic data and several problems concerned are investigated and discussed. It turns out in theory and practice that the relative error of the vertical gradient determined with the method is only 5%, and when the vertical gradient of gravity anomaly reaches the maximum 1 000 ns-2 the error is only 50 ns-2. In addition, how to divide ring zones in calculation and the errors caused by the inaccuracy of landform elevation and rock density has been quantitatively analysed.

关键词： vertical gradient gravity anomaly topographic mass geoid.

Determination of geoid and elevation of the Mt. Qomolangma and discussion on the role of vertical gravity gradient

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Chinese Science Bulletin 1997年第20期42卷 1723-1725页

作者： ZHANG Chijuninstitute of geodesy and geophysics, Chinese Academy of Sciences, wuhan 4.0077, china institute of geodesy and geophysics Chinese Academy of Sciences Wuhan China

IT is known that the Mt. Qomolangma is the highest peak in the world. It was recorded in the'Map of Complete Territory of the Qin Dynasty' (published in 1717). As the highest peak,the Mt. Qomolangma not only provokes the interest of climbers but also arouses much atten-tion of geodesists. A significant cause is that the Mt. Qomolangma is located in the collisionbelt between the Indian Plate and the Eurasian Plate. According to the relative

关键词： geoid orthometric height the Mt. Qomolangma.

Study on Decision Support System of Agricultural Sustainable Development of Jianli County in Jianghan Plain

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wuhan University Journal of Natural Sciences 2000年第3期5卷 334-338页

作者： Wang Xue\|lei, Liu Gong\|hu institute of geodesy and geophysics, Chinese Academy of Sciences, wuhan 4.0077 , china institute of geodesy and geophysics Chinese Academy of Sciences Wuhan China

With the agricultural development and the modernization of decision-making, it is necessary to establish the agricultural sustainable development decision support system supported by GIS. We set Jianli county as an example; our aim is to realize decision spatialiazation with the support of information system, remote sensing and artificial intelligence. The system components are described in the aspects of database, knowledge base, model-base and method-base. This system will provide a workable system for local decision-makers and agricultural management sections.

关键词： Key words agricultural sustainable development decision support system system function

Analysis and application of automatic deformation monitoring data for buildings and structures of mining area

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中国有色金属学会会刊：英文版 2011年第S3期21卷 516-522页

作者： XIAO Jie1, 2, 3, ZHANG Jin4 1. institute of geodesy and geophysics, Chinese Academy of Sciences, wuhan 4.0077, china 2. Key Laboratory of Dynamic geodesy, institute of geodesy and geophysics, Chinese Academy of Sciences, wuhan 4.0077, china 3. Graduate School of Chinese Academy of Sciences, Beijing 100049, china 4. Department of Surveying and Mapping, Taiyuan University of Technology, Taiyuan 030024, china institute of geodesy and geophysics Chinese Academy of Sciences Wuhan 430077 China Key Laboratory of Dynamic geodesy Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate School of Chinese Academy of Sciences Beijing 100049 China Department of Surveying and Mapping Taiyuan University of Technology Taiyuan 030024 China

The buildings and structures of mines were monitored automatically using modern surveying technology. Through the analysis of the monitoring data, the deformation characteristics were found out from three aspects containing points, lines and regions, which play an important role in understanding the stable state of buildings and structures. The stability and deformation of monitoring points were analysed, and time-series data of monitoring points were denoised with wavelet analysis and Kalman filtering, and exponent function and periodic function were used to get the ideal deformation trend model of monitoring points. Through calculating the monitoring data obtained, analyzing the deformation trend, and cognizing the deformation regularity, it can better service mine safety production and decision-making.

关键词： wavelet analysis Kalman filtering deformation monitoring data analysis mine

A new method of identifying and locating gross errors——Quasi-accurate detection

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Chinese Science Bulletin 1999年第23期44卷 2200-2204页

作者： OU Jikuninstitute of geodesy and geophysics , IMboratory of Dynamical geodesy , Chinese Academy of Sciences , wuhan 4.0077 , china institute of geodesy and geophysics Laboratory of Dynamical Geodesy Chinese Academy of Sciences Wuhan 430077 China

A new idea and a distinctive method have been proposed, which concern real errors and their estimators. By using the idea of 'Quasi-Stable Adjustment' created by Prof. Zhou Jiangwen for reference, the rank-deficient equations on real errors are resolved by adding the conditions under which the minimum of the norm of the real errors of the quasi-accurate observations is restrained.

关键词： least squares (LS) detection of gross errors (or outliers) hypothesis test robust estimation real errors.

Models and methods for precise determination of ionospheric delay using GPS

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Progress in Natural Science:Materials International 2007年第2期17卷 187-196页

作者： YUAN Yunbin, HUO Xingliang and OU Jikun ( institute of geodesy and geophysics, Chinese Academy of Sciences, wuhan 4.0077, china Graduate University of Chinese A-cademy of Sciences, Beijing 100039, china) institute of geodesy and geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate University Chinese Academy of Sciences Beijing 100039 China

The basic principles and methods for precisely determining ionospheric delays in GPS observations are introduced and discussed. Various methods and models for fitting ionospheric delays based on GPS are compared and a... 详细信息

关键词： GPS ionospheric delay atmosphere modeling precise GPS positioning.

Evolution of Jianghan Lakes and regional sustainable development

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Journal of Environmental Sciences 1999年第3期11卷 294-297页

作者： Cai Shu\|ming, Zhao Yan, Du Yun institute of geodesy and geophysics, Chinese Academy of Sciences, wuhan\ 4.0077,china 中科院测量与地球物理所湖北武汉 430077 中科院测量与地球物理所湖北武汉

Jianghan Lakes lie in the middle reaches of the Yangtze River. The evolution of the lakes during Holocene can be divided into three periods. Since Ming Dynasty, owing to natural factors and human activity, the lakes have accelerated the shrinking process. This has resulted in a series of rural and urban environmental problems, such as the disasters of flooding, inundation, and water\|logging; declination of aquatic resources; increase of diseases; swamping of lake districts; and deterioration of urban environment (taking wuhan City into consideration). In order to realize sustainable development in this area, several corresponding countermeasures should be taken.

关键词： Jianghan Lakes evolution of lakes environmental problems regional sustainable development.

Architecture and application of integrated spatial information service platform for digital mine

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中国有色金属学会会刊：英文版 2011年第S3期21卷 706-711页

作者： ZHANG Jin1, XIAO Jie2 1. College of Mining, Taiyuan University of Technology, Taiyuan 030024, china 2. institute of geodesy and geophysics, Chinese Academy of Sciences, wuhan 4.0077, china College of Mining Taiyuan University of Technology Taiyuan 030024 China institute of geodesy and geophysics Chinese Academy of Sciences Wuhan 430077 China

Using enterprise GIS platform, spatial databases and modern information technology, building geo-spatial information service platform of digital mine which has the features of the data exchange service, enterprise GIS services, directory services, logging services, is key technology and application infrastructure for digital mine. Based on the support of geospatial information service platform of digital mine, the professional GIS application service adapter can be developed and the application supports related to mining application system can be realized. Using high-resolution satellite remote sensing data, the mine functional partition map and geographic grids can be divided, and the geographic grid parts, status and events of important features of the surface object were investigated and defined. The system architecture and technical characteristics of integrated spatial information service platform were analyzed firstly, which guarantee service ability of digital mine. The methods and applications of functional partition map for integrated management service platform were discussed which are the services scheme of digital mine. The application results indicated that digital mine upgrades and enhances the capability and range of mine surveying and mapping, and is of great significance for guarantee of efficient, green and intensive exploitation of mine.

关键词： platform architecture web services application services digital mine