基于我国全球连续监测与评估系统的ERP测定的精度分析

利用GPS观测资料解算地球自转参数,用全球均匀分布的22个IGS跟踪站（IGS05）的连续观测资料估计地球自转参数（ERP）,并与IERSC04（UTC0时）的结果相比较,二者相差很小,均在IERS的ERP估计精度范围之内。基于即将建成的COMPASS全球连续监测与评估系统跟踪站,选择其网的8个IGS跟踪站的资料进行了解算并进行了分析和比对。     

方差-协方差分量估计公式等价性的进一步证明

通过附有条件的间接平差模型进一步证明各类方差-协方差分量估计公式之间的等价性。     

重力场的内蕴特性

根据从微分几何引入的重力场的5参量以及重力场的度量和联络系数,研究了力线、等位面、经线、纬线、子午线、平行圈的特性,并以5个定理的形式给出。     

GPS网与地面网的坐标连接

本文对坐标系统的转换以及坐标的拟合推估进行了论述。     

精密补偿器水准仪受地球磁场影响的检测统计分析

根据精密补偿器水准仪受地球磁场影响的检测统计,证实了磁场对不同型号的补偿器水准仪有不同程度的影响。分析了受磁影响的主要原因,并提出防磁措施及应注意的一些问题。     

联系参数函数不独立扩建网极大验后估计的方差分量估计公式

扩建网极大验后估计模型蕴含联系参数X2和扩建网观测量L2两个方差分量。将联系参数分解成函数不独立部分和函数独立部分,根据限制条件求出函数不独立部分代入扩建网观测方程消去不独立部分联系参数,推导了联系参数函数不独立扩建网极大验后估计的Helmert型、Welsch型和Forstner型方差分量估计。     

Progressive Transformation of a Flux Rope to an ICME

The solar wind conditions at one astronomical unit (AU) can be strongly disturbed by interplanetary coronal mass ejections (ICMEs). A subset, called magnetic clouds (MCs), is formed by twisted flux ropes that transport an important amount of magnetic flux and helicity, which is released in CMEs. At 1 AU from the Sun, the magnetic structure of MCs is generally modeled by neglecting their expansion during the spacecraft crossing. However, in some cases, MCs present a significant expansion. We present here an analysis of the huge and significantly expanding MC observed by the Wind spacecraft during 9 – 10 November 2004. This MC was embedded in an ICME. After determining an approximate orientation for the flux rope using the minimum variance method, we obtain a precise orientation of the cloud axis by relating its front and rear magnetic discontinuities using a direct method. This method takes into account the conservation of the azimuthal magnetic flux between the inbound and outbound branches and is valid for a finite impact parameter (i.e., not necessarily a small distance between the spacecraft trajectory and the cloud axis). The MC is also studied using dynamic models with isotropic expansion. We have found (6.2±1.5)×10²⁰ Mx for the axial flux and (78±18)×10²⁰ Mx for the azimuthal flux. Moreover, using the direct method, we find that the ICME is formed by a flux rope (MC) followed by an extended coherent magnetic region. These observations are interpreted by considering the existence of a previously larger flux rope, which partially reconnected with its environment in the front. We estimate that the reconnection process started close to the Sun. These findings imply that the ejected flux rope is progressively peeled by reconnection and transformed to the observed ICME (with a remnant flux rope in the front part).     

平面四参数法坐标转换在圆形基坑变形监测中的应用

由于基坑工程的监测工作往往会受到开挖深度、设计形状等各方面因素的影响和制约,导致监测方法和手段也不能一成不变.基于虚拟断面法仅适用于比较规则的多边形基坑,本文结合珠海市横琴新区基坑工程实例,提出使用平面四参数坐标转换法在圆形基坑中对基坑立柱水平位移计算的应用.结果表明:使用平面四参数坐标转换法计算基坑水平位移时,既不受...     

盾构机全站仪激光导向模式误差灵敏度分析

通过对盾构机全站仪激光导向系统的测量原理研究,并对盾构坐标与施工坐标系的旋转模型转换原理分析,建立盾构姿态参数与坐标旋转模型的关系.然后通过全站仪测量激光标靶棱镜和切口坐标与激光标靶相对位置的误差分析得到相关结论.