ERP精度对“嫦娥一号”差分VLBI定位精度的影响

推导了差分VLBI（ΔDOR）用于月球探测器定位的数学模型,利用嫦娥一号实测数据对探测器的位置和地球自转参数（ERP）同时进行了解算,并分析了ERP先验精度对定位精度的影响。     

Strain rate of the South American lithospheric plate by SIRGAS-CON geodetic observations

A multiyear solution of the SIRGAS-CON network was used to estimate the strain rates of the earth surface from the changing directions of the velocity vectors of 140 geodetic points located in the South American plate. The strain rate was determined by the finite element method using Delaunay triangulation points that formed sub-networks; each sub-network was considered a solid and homogeneous body. The results showed that strain rates vary along the South American plate and are more significant on the western portion of the plate, as expected, since this region is close to the subduction zone of the Nazca plate beneath the South American plate. After using Euler vectors to infer Nazca plate movement and to orient the velocity vectors of the South American plate, it was possible to estimate the convergence and accommodation rates of the Nazca and South American plates, respectively. Strain rate estimates permitted determination of predominant contraction and/or extension regions and to establish that contraction regions coincide with locations with most of the high magnitude seismic events. Some areas with extension and contraction strains were found to the east within the stable South American plate, which may result from different stresses associated with different geological characteristics. These results suggest that major movements detected on the surface near the Nazca plate occur in regions with more heterogeneous geological structures and multiple rupture events. Most seismic events in the South American plate are concentrated in areas with predominant contraction strain rates oriented northeast-southwest; significant amounts of elastic strain can be accumulated on geological structures away from the plate boundary faults; and, behavior of contractions and extensions is similar to what has been found in seismological studies.     

GPS,VLBI和SLR确定地心坐标的精度分析

为评价ＧＰＳ、ＶＬＢＩ和ＳＬＲ这３种空间技术确定地心坐标的真正实现精度,我们把３种技术在并置站上的地心坐标进行了相互比较。经过偏心改正和７个参数的转换后,可获得任意２种技术地心坐标不符值的加权中误差,以此作为外符精度。可以看出,ＶＬＢＩ与ＧＰＳ地心坐标三分量的外符精度在１ｃｍ之内,ＳＬＲ与ＶＬＢＩ和ＧＰＳ地心坐标三分量的外符精度在１～３ｃｍ之间。表明ＶＬＢＩ和ＧＰＳ实现的地心坐标精度比ＳＬＲ高一些     

1979-1999全球天测与测地VLBI观测资料处理结果与讨论

采用国际地民服务（ＩＥＲＳ）１９９６年规范和上海天文台甚长基线干涉测量（ＶＬＢＩ）资料分析软件,对自１９７９年８月以来全球约２９００次天测与测地ＶＩＢＬ实验进行了综合归算,得到６０１颗河外射电源在Ｊ２０００．０的坐标、１０１台站在Ｊ１９９７．０的坐标和运动速度、以及约２０年地地球定向参数序列。与国际相关结果的比较表明,归算结果不存在显著系统差。通过对归算结果的分析,指出目前国际上评估天球参考架局部     

陆地卫星五号TM图像系统纠正产品的几何精度分析

为了鉴定陆地卫星5号系统纠正TM图像产品的精度,我们以1:5万地形图为基准,对四景TM图像作了精度分析。结果表明,系统纠正后的TM图像产品,内部几何精度相当好,有较小的旋转、比例误差。采用一阶多项式即可建立TM图像和地形图之间的几何关系,其误差为1个像元左右。TM图像的大地绝对误差,可通过将整个TM图像沿x,y方向平移的方法来加以校正。     

类星体3C286的核位置──模型剖析

本文绘出类星体3C286在波长18cm的MERLIN图象和VLBI图象；对该源的射电结构提出了解释模型，也提供了进一步研究的方案．     

VLBI、SLR与时频

叙述VLBI、SLR对时频的要求,上海天文台VLBI、SLR的时频系统,并在此基础上重点介绍上海天文台有关方面的研究.     

自由波核章动的光学和新技术检测

本文应用当今最高精度的经典仪器光学观测资料、新技术的综合观测资料和单一的ＶＬＢＩ观测资料检测了自由液核章动，得到其周期为４１５—４１８天，分析了其运动形态为逆向的圆周运动，并计算了其振幅为亚毫秒级．     

南天区20个河外射电源的VLBI研究

本文报道南天区5GHzVLBI普查式观测结果．首次观测是在1992年11月期间进行的，共观测了23个河外射电源，获得了20个河外射电源的VLBI高分辨率的射电图象．有15个射电源呈现核喷流结构，1个有双向喷流，3个未分解，末发现有致密观源．在16个核喷流（包括一个双向喷流源）源中有11个呈现弯曲喷流现象．此外还首次发现有3个源中可能有超光速运动现象．     

以基线长度变化率为约束估算VLBI站的垂直形变率

基于NNR-NUVEL-1A地球板块运动模型和ITRF2000地球参考架的三维VLBI站速度矢量,采用实测的VLBI基线长度变化率作为约束,重新估计了部分国际VLBI站的局部或区域性地壳的垂直形变,并与国际地球参考架ITRFs解和VLBI全球解GLB2003,VTRF2003和VTRF2005的结果进行了比较。结果表明,欧亚板块的URUMQI站和太平洋板块的KWAJAL26站,南极OHIGGINS站的垂直形变率、ITRFs解和VLBI全球解存在6-15mm/a的差异,北美YUMA站可能有15-31mm/a 的垂直形变率,而美国西部太平洋板块的San Francisco(PRESIDIO)站的垂直形变率还有待进一步的研究。此外,SC-VLBA,CRIMEA和EFLSBERG站的垂直形变率、ITRFs解和VLBI全球解的差约为1-6mm/a。用不同方法得到的VLBI站的水平形变率解有较好的一致性。