约束条件对GPS水汽层析解算的影响分析

Influence Analysis of Constraint Conditions on GPS Water Vapor Tomography

对水汽层析中用到的各种约束条件进行详细阐述,并利用模拟的两个GPS网分析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。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,即使不采用其他观测手段获取的先验信息,也能得到可靠的层析解。

Various constraint conditions used in the tomography are presented in detail firstly.Then,their effects on the results of the tomography are analyzed based on two simulated GPS networks with different altitudes.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 prior information from other water vapor detectors.However,with great altitude difference between stations,the dependence of the tomography solution on a prior information is decreased obviously,and thus it can be got a reliable result even without a prior information.