薄板加权残值法用于近景摄影测量

着重介绍了一种数值力学方法薄板加权残值法用于处理近景摄影测量问题。通过实验证实这种方法在减少已知点数、改正近景像片的系统误差及提高解算精度方面的有效性。实验中采用了各种标准图型的模拟数据 ,并结合生产实例 ,从各个方面进行了探讨 ,得出了可靠的结果     

Characterization of the D beneath the Galapagos Islands using SKKS and SKS waveforms

SKS and SKKS waveforms from 16 events occurring between 2003 and 2005 in the Tonga Trench that were recorded by the BOLIVAR array are analyzed to determine the structure of the D layer beneath the Galapagos Islands.248 differential travel-time residuals of SKKS-SKS are measured and reveal a region of positive residuals of differential travel times in the northeast portion of the sampled region.Analyzing correlation statistics between the measured SKKS-SKS residuals and the observed absolute travel time dela...     

汶川8.0级地震序列联合定位研究

使用联合定位方法对2008年5月12日至7月7日M<,L>≥3.0的1 028次地震进行重新定位.针对EVT格式的波形数据,重新求取视出射角参数和到时参数,建立地震波到时与视出射角联合定位方法.视出射角参数对深度较敏感,其联合定位结果能保证经度和纬度方向上的定位精度,特别是能提高对深度的分辨能力.联合定位结果表明,地震...     

Discussion on the influence of truncation of ground motion residual distribution on probabilistic seismic hazard assessment

Recent studies on assessment of a very low annual probability of exceeding (APE) ground motions, 10-4 or less, have highlighted the importance of the upper bound of ground motions when very low probability results are acquired. The truncation level adopted in probabilistic seismic hazard analysis (PSHA) should be determined by an aleatory uncertainty model (i.e., distribution model) of ground motions and the possible maximum and minimum ground motion values of a specific earthquake. However, at the present ...     

基于EGM2008分析我国沿海陆地和岛礁高程异常

利用EGM2008地球重力场模型计算我国沿海13个省市的高程异常,结合实际的GNSS水准观测数据进行了比较分析,得出了GNSS水准实测的高程异常与EGM2008模型的高程异常之差的标准差是11 cm。     

顾及星间单差残差的GPS斜路径水汽含量估计

基于精密单点定位(precise point positioning,PPP)技术,对海上动态GPS斜路径水汽含量(SWV)估计进行研究。在现有计算方法的基础上,提出了顾及星间单差残差的SWV提取方法。利用渤海湾船载动态GPS测量数据和同步气象观测数据,对新方法的有效性进行了验证。结果表明,相对于MM5模式积分水汽结果,采用新方法计算的SWV值的RMS为1.2mm,比传统"非差残差法"减小了1mm。     

Co-Phased Median Filters, Some Peculiarities of Sweep Signal Processing

Median filters are nonlinear and a theoretical analysis of their behavior is very difficult and so are rarely used for the processing of seismic data. However, they are able to preserve steps, sharp discontinuities and edges that are lost using most other standard filters. As seismic data are mostly harmonic or frequency modulated signals in the frequency range 1 to 10 Hz, the median filter must be adapted so as to suppress noise but not unduly distort the signal. This can be accomplished by using a median filter whose length is n times that of signal period where n is even. By use of weighted-order statistics, samples of the signals closest in phase can be obtained. To illustrate the method, a signal from a frequency band of 6.3–7.5 Hz was processed and the quality of the signal enhanced two fold over the quality of the signal without processing.     

联邦滤波的改进算法

分析并综述了联邦滤波算法,以及该算法存在的问题。针对观测信息不足的情况下,结合抗差估计和自适应估计理论对联邦滤波算法进行了改进,给出了联邦滤波在局部传感器观测信息不足情况下的改进算法。由模拟计算结果可知,在局部传感器观测信息不足的情况下,改进的联邦滤波器能较好地抑制载体观测异常和状态扰动异常对动态系统参数估值的影响,具有很强的的抗差性和自适应性。     

残差绝对值和最小法在单线阵CCD卫星影像后方交会粗差探测中的应用

利用残差绝对值和最小法进行单线阵CCD卫星影像的后方交会，一般来说，不仅可以克服外方位元素之间的强相关性，而且可以有效地剔除粗差。实验证明该方法简便、稳健、有效。     

从天文观测提取地震前兆信息

天文时间和纬度观测的残差值在仪器周围地区发生中强地震前夕出现短期异常的现象已被初步证实．本文进一步讨论时纬残差异常与地震三要素的关系，并认为布设观测网点获得多架仪器的资料，将可为地震三要素，尤其对震中位置的判定提供有意义的信息．多架仪器的资料对垂线变化和垂线偏差研究也将是有价值的．建议在地震高发地区组建观测网，并研制主要用于地学研究的小型、高精度天文时纬观测仪器．