Characteristics of horizontal crustal deformation in Japan as deduced from frequency distribution of maximum shear strain rate

In order to study characteristics of horizontal crustal strains, we divide the Japanese Islands into 14 tectonic provinces consistent with the suggestion given byMatsuda (1990). We calculate frequency distribution of strain rates using the results of the Precise Control Survey initiated by the Geographical Survey Institute in 1973. This survey is a revision of old first- and second-order triangulation networks by trilateration. The principal axes and principal strains inside all the geodetic triangles are deduced from the comparison of the old triangulation and the new trilateration networks. The maximum shear strain rates are calculated by dividing the accumulated strains with the time intervals. The frequency distribution of strain rates is counted for each tectonic province and for the entire Japanese Islands. It is proved that the maximum shear strain rate with highest frequency ranges from 0.10–0.15 microstrain/a for 4409 data in the Japanese Islands. The mean value of the strain rates throughout the Japanese Islands is deduced to be 0.18 microstrain/a. We also calculated a mean value of strain rates for each tectonic province. Comparison is made between mean geodetic strain rates in the provinces and Quaternary strain rates estimated by geomorphic data. It is found that 0.3–0.4 microstrain/a of the highest order strain rate is now prevailing in the Izu province, the south Fossa-Magna collision zone, and some special provinces along the eastern part of the Japan Sea coast.     

利用精密星历进行单点定位的数学模型和初步分析

精密单点定位(Precise Point Positioning,简称PPP),是相对于一般的单点定位而言的,它是利用GPS的精密星历和钟差文件,以载波相位和伪距为观测资料,进行独立的单点精密定位.它的特点在于各站的解算相互独立,计算量远远小于一般的相对定位.尝试以伪距为观测值,利用JPL给出的精密星历(*.sp3)和钟差(*.clk),进行精密单点定位的试验,取得了初步的结果.     

峨嵋山地区块体图的计算机绘制

本文介绍了用计算机辅助设计软件AUTOCAD与三维动画软件3DMAX来绘制峨嵋山地区块体图的方法，以此为例子讲述了将地形图改画面三维图的具体操作步骤，并进一步论述了用计算机绘制块体图的方法有着广泛的应用及其实用价值。     

铀矿地质档案计算机管理的安全与技术分析

通过对铀矿地质档案现状与技术安全分析，以及考虑经济因素，铀矿地质档案计算机管理应以磁存储技术和光盘存储技术相结合，采用档案修复和转化技术完成档案的介质转化存储，实现了电子档案管理。     

一种新的二进制地图矢量文件格式设计

比较了二制文件与文本文件的优点,以线状数据为例设计了便于文档序列化,易于面向对象ＧＩＳ进行了的二进矢量地图文件格式。     

GPS广播星历参数拟合算法的探讨

介绍了全球定位系统(GPS)的广播星历参数拟合算法,在推导卫星位置对GPS广播星历参数偏导数的基础上,导出了调和项对偏导数的影响函数。计算结果表明,考虑调和项并不能提高GPS广播星历参数拟合的精度和效率,实际应用时应忽略调和项的影响。     

基于二维矢量数字地图的水印算法研究

通过分析MQUAD算法的一些缺陷，提出通过点坐标漂移重置在二维矢量地图中嵌入水印的方法，并通过DXF格式地图予以实现。     

Matlab对基于HDF格式的MODIS 1B数据的提取方法与实现

基于HDF文件格式的MODIS数据的应用越来越广泛,MODIS数据开发应用的前提是对MODIS 1B数据的提取。本文详细介绍了利用Matlab对HDF文件进行读写操作的过程,在此基础上给出了提取MODIS 1B数据的流程图,实现了对MODIS 1B数据的提取,为MODIS二级产品的开发打下了基础。     

Precise orbit determination for the GRACE mission using only GPS data

The GRACE (gravity recovery and climate experiment) satellites, launched in March 2002, are each equipped with a BlackJack GPS onboard receiver for precise orbit determination and gravity field recovery. Since launch, there have been significant improvements in the background force models used for satellite orbit determination, most notably the model for the geopotential. This has resulted in significant improvements to orbit accuracy for very low altitude satellites. The purpose of this paper is to investigate how well the orbits of the GRACE satellites (about 470 km in altitude) can currently be determined using only GPS data and based on the current models and methods. The orbit accuracy is assessed using a number of tests, which include analysis of orbit fits, orbit overlaps, orbit connecting points, satellite Laser ranging residuals and K-band ranging (KBR) residuals. We show that 1-cm radial orbit accuracy for the GRACE satellites has probably been achieved. These precise GRACE orbits can be used for such purposes as improving gravity recovery from the GRACE KBR data and for atmospheric profiling, and they demonstrate the quality of the background force models being used.