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Time Series Correlated Error's Simulation Scheme with the Application to Simulate the Ephemerides Error of CHAMP

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测绘学报 2002年第Z1期31卷 27-30页

作者： SHEN Yun zhong 1 , HSU Hou tse 2.(1. Department of Surveying and Geo informatics,Tongji University,Shanghai 2.0092.{3. 2. Institute of geodesy and {2., CAS, Wuhan 43.077,{3.) Department of Surveying and Geo-informatics Tongji University 上海 200092 Wuhan 430077

Computer simulation experiment is very important in the phase of project design, the availability of simulated result highly depends on the scheme of error simulation. Time series observations are normally correlated. This paper first discusses the formula of correlated error propagation, then derives the formula of simulating time series correlated errors. This formula is then used to simulate correlated ephemerides errors of CHAMP, then the ephemerides are used to recover the gravity vector at satellite altitude with finite differential formula. The formulae derived in this paper are verified with the difference between the recovered gravity vectors and the `true values’ which are directly computed with the same gravity model as that generating the ephemerides.

关键词： time series observation simulation of correlated errors CHAMP ephemerides

A numerical study on nonlinear propagation and short-term variability of the migrating diurnal and semidiurnal tides

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chinese Science Bulletin 2005年第17期50卷 1940-1948页

作者： HUANG Chunming1,2. ZHANG Shaodong1,2.& YI Fan1,2.1. School of Electronic Information, Wuhan Universiy, Wuhan 43.079, {3. 2. Key Laboratory of Geospace Environment and geodesy, Ministry of Education, Wuhan University, Wuhan 43.079, {3. School of Electronic Information Wuhan University Wuhan 430079 China Key Laboratory of Geospace Environment and geodesy Ministry of Education Wuhan University Wuhan 430079 China

By using a three-dimensional fully nonlinear numerical model in spherical coordinates and taking the linear steady solutions of the migrating diurnal and semidi-urnal tides in January from the Global-Scale Wave Model (GSWM) as the initial values, we simulate the linear and nonlinear propagations of the migrating diurnal and semidi-urnal tides in the atmosphere from the ground to the lower thermosphere. A comparison of our simulations with the results of GSWM is also presented. The simulation results show that affected by the nonlinearity, the migrating diurnal and semidiurnal tides propagating in the middle and upper atmosphere exhibit evident short-term variability. The nonlinear interactions between the migrating tides and the background atmosphere can obviously alter the background wind and temperature fields, which suggests that the nonlin-ear propagations of the migrating diurnal and semidiurnal tides impact significantly on the transient dynamical and thermal structures of the background middle and upper at-mosphere and the nonlinear effect is an important cause of the difference between the results of GSWM and observa-tions.

关键词：大气非线性传播数学模型可变性温度场

Separation of systematic errors in processing high precision GPS baselines

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中国有色金属学会会刊：英文版 2005年第S1期15卷 139-141页

作者： WANG Zhen-jie~(1, 2., QU Guo-qing~2.(1. Institute of Architectural Engineering, Shangdong University of Technology, Zibo 2.5012. china 2. Institute of geodesy and {2., chinese Academy of Sciences, Wuhan 43.077,china) Shandong Univ Technol Inst Architectural Engn Zibo 255012 Peoples R China chinese Acad Sci Inst Geodesy & Geophys Wuhan 430077 Peoples R China

The research is based on the double difference observations and semi-parametric model. Systematic errors are considered as the parameters to be estimated, and brought into the GPS observation equations. High precision baselines are obtained after separating systematic errors. The crucial steps are choosing regularizer and regularization parameters in processing GPS systematic errors by using the semi-parametric model. We propose a new regularizer and apply it to dealing with systematic errors. Also, we compare it with one proposed by other researchers. This comparison is done when all the regularization parameters equal to one. The computation result of the example shows that two regularizers correspond well and they can separate systematic errors successfully. Thus, we can get high precision baselines. Compared with R=QK-1Q′, our regularizer R=GTG is simple, so, the process of resolving the high precision baselines is relatively simple.

关键词： GPS systematic errors semi-parametric model regularizer

Method of multi-level recursive and application to nonlinear dynamic deformation forecasting

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中国有色金属学会会刊：英文版 2005年第S1期15卷 172-175页

作者： LIU Guo-lin~(1, 2., ZHANG Lian-peng~2. OU Ji-kun~1 (1. Institute of geodesy and {3., {2. Academy of Science, Wuhan, 43.077,china 2. Shandong University of Science and Technology, Tai’an 2.1019, china) chinese Acad Sci Inst Geodesy & Geophys Wuhan 430077 Peoples R China Shandong Univ Sci & Technol Tai An 271019 Peoples R China

The time-dependence bilinear mixed-regression deformation model and time-dependence bilinear dynamic system deformation model are established for deformation observation series. According to the multi- level recursive method, the time-dependence parameters are first traced and predicted, and then the dynamic system states. Due to the method considering time-dependence of deformation and having stronger adaptability to time-dependence system, it can improve forecast’s precision. It is very effective for data processing of nonlinear dynamic deformation monitoring to make multi-step forecasting.

关键词： multi-level recursive dynamic monitoring timedependence parameters

Solving ill-conditioning observation equations via truncated SVD

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中国有色金属学会会刊：英文版 2005年第S1期15卷 142-144页

作者： GUI Qing-ming~1, GUO Jian-feng~(1, 2. (1. Institute of Science, Information Engineering University, Zhengzhou 450001, china 2. Institute of {3. and {2., chinese Academy of Science, Wuhan 43.077, china ) Informat Engn Univ Inst Sci Zhengzhou 450001 Peoples R China chinese Acad Sci Inst Geodesy & Geophys Wuhan 430077 Peoples R China

To mitigate the ill effects and obtain more accurate and stable solution of the observation equations, the so-called truncated singular-value decomposition (TSVD) method is introduced by modifying the small (nonzero) singular values of the coefficients matrix. The proposed method directly disposed the ill-conditioning observation equations, which differs considerably from the traditional normal equation method. An application explains that TSVD can mitigate the ill conditioning.

关键词： ill conditioning condition number truncated SVD

Wetland vegetation biomass estimation and mapping from Landsat ETM data: a case study of Poyang Lake

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Journal of Geographical Sciences 2002年第1期12卷 35-41页

作者： LI Ren-dong1, 2. LIU Ji-yuan2.(1. Institute of geodesy and {3., CAS, Wuhan {2., china 2. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101 china) Institute of geodesy and geophysics CAS Wuhan China Institute of Geographic Sciences and Natural Resources Research CAS Beijing China

Poyang Lake is the largest freshwater lake in china. This paper conducted a digital and rapid investigation of the lake’s wetland vegetation biomass using Landsat ETM data acquired on April 16, 2.00. First, utilizing the false color composite derived from the ETM data as one of the main references, the authors designed a reasonable sampling route for field measurement of the biomass, and carried it out on April 18–2., 2.00. Then after both the sampling data and the ETM data were geometrically corrected to an equal-area projection of Albers, linear relationships among the sampling data and some transformed data derived from the ETM data and the ETM 4 were calculated. The results show that the sampling data is best relative to the band 4 data with a high correlation coefficient of 0.86, followed by the DVI and NDVI data with 0.83.and 0.80 respectively. Therefore, a linear regression model, which was based on the field data and band 4 data, was used to estimate the total biomass of entire Poyang Lake, and then the map of the biomass distribution was compiled.

关键词： Poyang Lake biomass wetland vegetation Landsat ETM data

The gravitational gradient tensor’s invariants and the related boundary conditions

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Science china Earth Sciences 2010年第5期53卷 781-790页

作者： YU JinHai1,2.3.& ZHAO DongMing4 1 College of Earth Science, Graduate University of chinese Academy of Sciences, Beijing 100049, china 2.Institute of {2. and geophysics, chinese Academy of Sciences, Wuhan 43.077, china 3.State Key Laboratory of Astronautic Dynamics, Xi’an 710043. china 4 Zhengzhou Institute of Surveying and Mapping, Zhengzhou 450052. china 1. College of Earth Science Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China3. State Key Laboratory of Astronautic Dynamics Xi’an 710043 China4. Zhengzhou Institute of Surveying and Mapping Zhengzhou 450052 China

Here we report new approaches of recovering the Earth gravitational field from GOCE (Gravity field and steady-state Ocean Circulation Explorer) gradiometric data with the help of the gradient tensor’s invariants. Our results only depend on GOCE satellite’s position and gradiometry, in other words, they are completely independent of the satellite attitude. First, starting from the invariants, linearization models are established, which can be referred as the general boundary conditions on the satellite’s orbit. Then, the spherical approximation expressions for the models are derived, and the corresponding solving methods for them are discussed. Furthermore, considering effects of J2.term, the spherical approximation models are improved so that the accuracies of the boundary conditions can be theoretically raised to O ( J 2.2.T), which is approximately equivalent to O(T2.. Finally, some arithmetic examples are constructed from EGM96 model based on the derived theories, and the computational results illustrate that the spherical models have accuracies of 10-7 and the order recovering the gravitational field can reach up to 2.0, and the models with regard to effect of J2.term have accuracies of 10-8 and the order can reach up to 2.0.

关键词： the Earth’s gravitational field gravitational gravidiometry tensor’s invariant

Triaxial ellipsoid models of the Moon based on the laser altimetry data of Chang'E-1

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Science china Earth Sciences 2010年第11期53卷 1594-1601页

作者： WANG WenRui1,2.3. LI Fei1, LIU JianJun1, REN Xin2. ZOU XiaoDuan2.3. MU LingLi2. YAN JianGuo1, ZOU YongLiao2. ZHANG HongBo2. Lü Chang2. LIU JianZhong2. ZUO Wei2. SU Yan2. WEN WeiBin2. BIAN Wei2. WANG Min2. LI ChunLai2.& OUYANG ZiYuan2.1 School of geodesy and Geomatics, Wuhan University, Wuhan 43.079, china 2.National Astronomical Observatory of {2. Academy of Sciences, Beijing 100012. china 3.Graduate School of {2. Academy of Sciences, Beijing 100049, china 1. School of geodesy and Geomatics Wuhan University Wuhan 430079 China2. National Astronomical Observatory of Chinese Academy of Sciences Beijing 100012 China3. Graduate School of Chinese Academy of Sciences Beijing 100049 China

Lunar geodetic parameters, which play an important role in lunar exploration, can be calculated from the gravity and topography data. With the CE-1 altimetry data and LP gravity model, we calculate such geodetic parameters as the principle moment of inertia, the principle inertia axes, equatorial radius, polar radius, mean radius, flattening and offset between center of mass and center of figure (DCOM-COF). According to the CE-1 altimetry data and the above geodetic parameters, a tri-axial ellipsoid (CE-1-LAM-GEO) and a tri-axial level ellipsoid (CE-1-LAM-LEVEL) are calculated individually, providing mass center and figure center offset (DCOM-COF) and parameters more reliable in direction and magnitude.

关键词： Chang’E-1 laser altimetry data lunar ellipsoid lunar gravity

A new method of ionospheric-free hybrid differential positioning based on a double-antenna CAPS receiver

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Science china(Physics,Mechanics & Astronomy) 2009年第3期52卷 368-375页

作者： GUO JinYun1,2. HAN YanBen1 & CHANG XiaoTao3.1 National Astronomical Observatories, chinese Academy of Sciences, Beijing 100012. {3. 2.College of {2. and Geomatics, Shandong University of Science and Technology, Qingdao 2.6510, {3. 3.chinese Academy of Surveying and Mapping, Beijing 10003., {3. 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China 2. College of geodesy and Geomatics Shandong University of Science and Technology Qingdao 266510 China 3. chinese Academy of Surveying and Mapping Beijing 100039 China

chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the chinese Academy of Sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPS receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). So it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPS navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPS GEO and IGSO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor changes in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPS satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.

关键词： chinese Area Positioning System (CAPS) ionospheric-free linear combination double-antenna receiver hybrid differential positioning method