Modeling the VLBI delay for Earth satellites
Modeling the VLBI delay for Earth satellites
复制标题
模拟地球卫星的 VLBI 延迟
DOI：
10.1007/s00190-018-1217-0
复制
发表时间：
2018
影响因子：
4.4
通讯作者：
Nothnagel A
中科院分区：
文献类型：
--
作者：
Jaron F;Nothnagel A
对围绕地球运行并发射人造无线电信号的卫星的甚长基线干涉测量(VLBI)观测有可能成为改善天地参考系之间的框架联系的一项重要技术。对基线上一个站相对于另一个站的信号接收时延进行建模是相关和参数估计的基本步骤。到目前为止开发的近场VLBI延迟模型包括数值计算，这可能会在计算时间方面变得昂贵。这尤其适用于要计算偏导数的情况，这是最小二乘平差的正常情况。此外，所有的模型都是在质心天文参考系中建立的，需要大量的数据。在这里，我们给出了地面射电望远镜观测到的卫星绕地球运行的特殊情况下的VLBI延迟的解析表达式。在对卫星轨道线性化的简化下，我们解析地求解了从源到接收器一和到接收器二的每条信号传播路径的光时间方程。通过在短信号传播时间内将地球的运动近似为均匀的，我们能够在地心天文参考系中工作。我们通过模拟地球卫星的VLBI观测来研究数值解和解析解之间的差异。这些测试表明，在VLBI检测水平以下，用解析公式计算的时延与用数值解计算的时延是一致的，但计算量更小。
Very-long-baseline interferometry (VLBI) observations of satellites orbiting the Earth and emitting an artificial radio signal have the potential of becoming an important technique for improving the frame ties between celestial and terrestrial reference frames. Modeling the delay of the signal reception at one station with respect to the other station of a baseline is a fundamental step for correlation and parameter estimation. The near-field VLBI delay models developed so far include numerical computation, which may become expensive in terms of computation time. This applies especially when partial derivatives are to be computed, which is the normal case for least squares adjustments. Furthermore, all the models are formulated in the barycentric celestial reference system requiring large numbers. Here we present an analytical expression for the VLBI delay for the special case of satellites orbiting the Earth, observed by ground-based radio telescopes. We analytically solve the light time equation for each signal propagation path from the source to receiver one and to receiver two under the simplification of linearizing the trajectory of the satellite. By approximating the motion of the Earth as uniform during the short signal travel times we are able to work in the geocentric celestial reference system. We investigate differences between numerical and analytical solutions by simulating VLBI observations of Earth satellites. These tests reveal that delays computed with the analytical formula are consistent with those computed with the numerical solution below the detection level of VLBI but at less computational cost.
影响因子：
4.4
作者：
Plank L;Hellerschmied A;McCallum J;Böhm J;Lovell J
通讯作者：
Lovell J
影响因子：
6.5
作者：
Duev, D. A.;Molera Calves, G.;Bahamon, T. Bocanegra
通讯作者：
Bahamon, T. Bocanegra
太空大地测量参考天线 (GRASP) 任务概念
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
Y. Bar;B. Haines;S. Wu
通讯作者：
S. Wu