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Search Results: 1 - 10 of 3467 matches for " Institute of Geodesy "
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Wavelets in airborne gravimetry
航空重力测量数据的小波滤波处理
LIU Lin Tao XU Hou Ze Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan,China,
柳林涛,许厚泽
地球物理学报 , 2004,
Abstract: Three sets of continuous wavelets are constructed for the filtering processing of airborne gravimetry data. The continuous wavelet filters are used to perform the low passing, first order derivative and second order derivative filterings at expected space (or time) scales for the airborne gravimetry data. Here we focus on how to construct the continuous wavelet filters and show their working principle. Particularly the technical parameters (window width parameter and scale parameter) of the filters are tested. The advantages of the continuous wavelet filters over the conventional digital filters are also discussed. We make some filtering tests, which show the feasibility and effectiveness of applying the continuous wavelet filters to airborne gravimetry.
COMBINED RIDGE WITH SHRUNKEN ESTIMATOR AND ITS APPLICATIONS IN GEODETIC ADJUSTMENT
岭—压缩组合估计及其在测量平差中的应用
Gui Qingming,{,},Li Guozhong,{},Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan Institute of Surveying,Mapping,Information Engineering University,Zhengzhou,
归庆明,李国重
大地测量与地球动力学 , 2002,
Abstract: On the basis of analyzing ordinary ridge estimator's and Stein estimator's properties, a new biased estimator of unknown parameters, which is called combined ridge with shrunken(CRS)estimator, is generated for Gauss-Markov model by combining the ordinary ridge estimator and Stein shrunken estimator.The CRS estimator can overcome the defects of the ordinary ridge estimator and the Stein shrunken estimator.Its properties in the mean squared error and under the Pitman's measure of closeness are investigated.In the sense of the mean squared error comparisons between these biased estimators are explored.The determination of biased parameter of the CRS estimator is discussed and some important conclusions are drawn.The theoretical and computational results demonstrate that the CRS estimator is a potentail estimtor in surveying adjustment.
THE INTEGRAL SOLUTION OF THE DIRICHLET''''S BOUNDARY VALUE PROBLEM ON THE ELLIPSOID INTERFACE WITH THE ACCURACY OF O(T2)
O(T2)精度下椭球界面Dirichlet边值问题的积分解
YU Jin Hai Wuhan Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan,China Zhengzhou Institute of Surveying,Mapping,Zhengzhou,China,
于锦海
地球物理学报 , 2004,
Abstract: 研究了边界是参考椭球面的Laplace方程Dirichlet边值问题的求解 ,在O(ε4 ·T)精度下给出了参考椭球界面上扰动重力位Dirichlet外问题的积分解式 .该结果理论上优于目前常用的球近似下的积分解式 ,从而为研究物理大地测量中边值问题的求解提供了新的依据 .
Variational Approach to Free Motion in the Earth''''s Fluid Outer Core
液核自由运动的变分方法
XU Jian Qiao,SUN He Ping FU Rong Shan College of Earth,Space Sciences,University of Science,Technology of China,Hefei,China Key Laboratory of Dynamic Geodesy,Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan,China,
徐建桥,孙和平,傅容珊
地球物理学报 , 2004,
Abstract: 从流体静力平衡地球的弹性-引力运动动量方程出发，以角动量方程控制弹性地幔、液态外核和弹性内核之间的相对转动，在球对称近似下考虑了地幔和内核对液核边界扰动的形变响应，并以此作为液核边界运动的约束条件．根据地球简正模对称性的一般特征，建立了自转、非黏性、椭球分层流体外核自由振荡运动的变分原理并给出了相应的泛函．
Resolution estimation of Earth gravity field recovery through the low_low satellite to satellite technology by numerical simulation
数值模拟估算低低卫-卫跟踪观测技术反演地球重力场的空间分辨率
ZHOU Xu-Hua,WU Bin,XU Hou-Ze,PENG Bi-Bo Key Laboratory of Dynamic Geodesy,Institute of Geodesy & Geophysics,Chinese Academy of Sciences,Wuhan,China,
周旭华,吴斌,许厚泽,彭碧波
地球物理学报 , 2005,
Abstract: 从两个方面模拟研究了低低卫-卫跟踪观测技术恢复地球重力场的空间分辨率.利用重力位系数作为扰动量,积分30天的轨道,研究重力位系数变化引起低低卫-卫跟踪星间距离和速率变化,结果表明,对于地球重力场模型EGM96的前12 0阶,99 8%和97%的位系数扰动引起星间距离和速率变化的均方差大于1×10 - 5m和1×10 - 7m s ,并且星间距离观测值对地球重力场的反应更为敏感.不考虑非保守力误差的影响,用随机误差为1×10 - 5m和1×10 - 6 m s的星间距离和速率变化作模拟观测量,恢复了78阶地球重力场位系数,结果表明,采用随机误差为1×10 - 5m的星间距离恢复地球重力场的精度明显高于1×10 - 6 m s的星间速率结果,但是如果考虑非保守力误差影响,则星间测速的优越性大大增强.
Theoretical computation of the barometric pressure effects on deformation, gravity and tilt
大气变化对位移、重力和倾斜观测影响的理论计算
LUO Shao-Cong,SUN He-Ping,XU Jian-Qiao Key Laboratory of the Dynamic Geodesy,Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan,China,
罗少聪,孙和平,徐建桥
地球物理学报 , 2005,
Abstract: Based on the loading theory of an elastic earth,and the distributions of dry air and its vertical gradients of temperature under hydrostatic equilibrium,we have theoretically modeled the effects of barometric pressure on the observations of deformation,gravity and tilt.The influences of many factors,such as the adopted earth models,station height,topography around station,surface temperature and water vapor in atmosphere,on the final results are taken into account and discussed in detail.The numerical results show that the elastic effects mainly come from the atmosphere in the area far away from the station.The direct effects on gravity come from the contribution of the air in the area near the station,while those on tilt from the contribution of the air in the area far away from the station.The influences of all these factors on the atmospheric gravity and tilt Green's functions mainly occur in the range of the angular distance less than 0.1 and 1 degrees,respectively,but their comprehensive influence is extremely complicated.
vDetermination of geoid by GPS/Gravity data
应用GPS/重力数据确定（似）大地水准面
LI Fei,YUE Jian-Li,ZHANG Li-Ming,School of Geodesy,Geomatics of Wuhan University,Wuhan,China Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan,China Graduate School of the Chinese Academy of Sciences,Beijing,China,
李斐,岳建利,张利明
地球物理学报 , 2005,
Abstract: As an application and test of GPS/Gravity boundary value problem, a local geoid located on N area is determined, by using 702 GPS/Gravity data for calculation and 52 GPS/Leveling for matching and checking. The accuracy analyses by matching with GPS/Leveling data and by direct correction to system difference show that the determination of local geoid computed by GPS/Gravity data and method of GPS/Gravity BVP achieved centimeter accuracy.
DETECTION OF LONG-PERIOD CORE MODES BY USING THE DATA FROM GLOBAL SUPERCONDUCTING GRAVIMETERS
利用全球超导重力仪数据检测长周期核模
XU Jian-Qiao,SUN He-Ping,FU Rong-Shan Key Laboratory of Dynamic Geodesy,Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan,China College of Earth,Space Sciences,University of Science,Technology of China,Hefei,China,
徐建桥,孙和平,傅容珊
地球物理学报 , 2005,
Abstract: Possibility of detection of the long-period core modes is discussed by using the long-term gravity observations recorded with 13 superconducting gravimeters (SGs) in a worldwide network of the Global Geodynamics Projects. Identical techniques are used to remove the luni-solar gravity tides, the long-term trends of instrument drift, and the effects of atmospheric pressure from all 13 SG data sets. The power spectral density of each data set, as well as the product spectral density of all the data sets, is evaluated. The background noise levels in various non-tidal bands are estimated and analyzed. The results indicate that the background noise level of the global SG observations is 0 0649 nm/s2 in the inter-tidal band from 0 047 to 0 075cph, 0 0350 nm/s2 in another inter-tidal band from 0 089 to 0 117cph, and 0 0138 nm/s2 in the sub-tidal band from 0 172 to 0 333cph. The magnitude thresholds of any global harmonic signals, which may be detected by the global SGs, in these three non-tidal bands are 0 0416, 0 0231and 0 0098 nm/s2, respectively. It implies that the signals, related to the long-period core modes, may be identified in the global SG observations, if they exist. The spectral peaks of the global harmonic signals with periods of 16 55, 15 79, 11 00 and 10 09h are detected in the two inter-tidal bands of the global SG records; and they may come from the long-period oscillations in the fluid outer core of the Earth. In the sub-tidal band, there is no obvious peak relating to the Slichter triplet claimed by Smylie in 1992 Instead, 8 spectral peaks of global harmonic signatures significantly emerge from the background noise. Comparing their periods with those of the Slichter triplet predicted theoretically, it may be concluded that the Slichter triplet is one of the possible resources of three peaks of them.
KINEMATIC ORBIT DETERMINATION OF GEO SATELLITE BASED ON KALMAN FILTERING
基于Kalman滤波的GEO卫星运动学定轨
He Kaifei,Xu Tianhe,School of Geology Engineering,Geomatics,Chang'an University,Xi'an School of Geodesy,Geomatics,Wuhan University,Wuhan Xi'an Research Institute of Surveying,Mapping,Xi'an,
贺凯飞,徐天河
大地测量与地球动力学 , 2009,
Abstract: Considering the features of the motion of GEO(Geostationary Earth Orbit) satellite,Kalman filtering by using constant velocity model as state equation is proposed.When there exists systematic errors,forward and backward filtering is used,and when not,forward filtering.And the idea behind forward and backward filtering is that,firstly,using forward filtering estimates systematic error parameters,then the values obtained are used to do backward filtering.The simulation results show when there exists only rand...
Gravity change detected by repeated absolute gravity measurements in the western Yunnan and Lhasa, China and its implication
重复绝对重力测量观测的滇西地区和拉萨点的重力变化及其意义
WANG Yong ZHANG Wei Min ZHAN Jin Gang HAO Xing Hua WANG Hu Biao XU Hou Ze Institute of Geodesy,Geophysics,Chinese Academy of Sciences,Wuhan,China,
王勇,张为民,詹金刚,郝兴华,王虎彪,许厚泽
地球物理学报 , 2004,
Abstract: 根据近年来在滇西地区和西藏拉萨绝对重力点上的一些新的绝对重力重复观测结果 ,对 1990年以来在这些点上绝对重力重复观测结果进行了分析 .滇西地区的 5个绝对重力观测点的近 10年的重复观测结果表明 ,大部分观测时段没有出现与地球动力学事件有关的重力变化 ,只有丽江和洱源 2个绝对重力观测点的观测结果显示丽江地震前后有变化 .为了研究该重力变化的原因 ,本文正演模拟了出现重力变化期间丽江地震同震位错引起的重力变化 ,模拟结果与实际观测结果有较好的一致性 .西藏拉萨近 10年以来的重复观测结果给出了拉萨点的绝对重力值以 - 1.82± 0 .9× 10 - 8m·s- 2 ·a- 1 速率下降 ,这从重力学的角度反映出青藏高原的隆升 .对拉萨点的重力变化机制进行了探讨 ,根据印度板块与欧亚大陆俯冲模型计算的拉萨点重力变化速率与观测到的重力变化速率较一致 ,表明现今拉萨地区重力变化是由于印度板块与欧亚大陆俯冲所引起 .根据印度板块向欧亚大陆俯冲的位错模型计算的拉萨点的重力变化与地表垂直位移的关系 ,将重力变化转换为拉萨点的隆升速率为 8.7mm a .
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