测绘学报

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约束条件对GPS水汽层析解算的影响分析

于胜杰,柳林涛,梁星辉   

  1. 中国科学院测量与地球物理研究所
  • 收稿日期:2009-12-21 修回日期:2010-03-09 出版日期:2010-10-25 发布日期:2010-10-25
  • 通讯作者: 于胜杰

Influence Analysis of Constraint Conditions on GPS Water Vapor Tomography

  1. 1.
    2. Institute of Geodesy and Geophysics, CAS
  • Received:2009-12-21 Revised:2010-03-09 Online:2010-10-25 Published:2010-10-25

摘要: 附加约束条件的层析解算是解决GPS水汽层析观测方程不适定性的主要方法之一。本文对水汽层析中用到的各种约束条件进行了详细阐述,并利用模拟的两个GPS网分析了约束条件对层析解算的影响。结果表明,当水汽在水平方向变化较为平缓时,水平约束方程的权阵对层析结果具有较大的影响。另外,当GPS网测站间的相对高差较小时,仅利用GPS技术很难实现对水汽的准确监测,且层析结果的可靠性在很大程度上依赖于先验信息的精度。但是,对于测站间相对高差较大的GPS网来说,层析结果对先验信息的依赖性明显减弱,即使不采用其它观测手段获取的先验信息,也能得到可靠的层析解。

Abstract: Adding reasonable constraint conditions to the observation equation is one of the main methods to solve the ill-posed problem in the GPS water vapor tomography. Various constraint conditions used in the tomography are presented in detail firstly. Then, its effect on the result of the tomography is analyzed based on two simulated GPS networks with different altitude. As the results shown, with the water vapor changing gently in horizontal direction, the weight matrix of horizontal constraints have a large effect on the result of the tomography. In addition, with small altitude differences between stations in the GPS network it will be difficult to detect the water vapor only using the GPS technique, and the solution of the tomography relies highly on the accuracy of a priori information from other water vapor detectors. However, with large altitude difference between stations, the dependence of the tomography solution on a priori information is decreased obviously, and we thus can get a reliable result even without a priori information.