附加虚拟信号精化水汽层析模型的方法

在全球导航卫星系统（global navigation satellite system，GNSS）水汽层析中，受卫星星座和接收机几何分布的影响，穿过层析区域的射线条数有限。针对该问题，设计并实现了一种附加虚拟倾斜路径信号精化水汽层析模型的方法，该方法能够增加穿过研究区域的射线条数和射线穿过的网格数，使层析结果更加逼近真值。利用香港卫星定位参考站网2015年5月共31 d的GPS网实测数据和气象数据进行实验，并结合无线电探空数据验证该方法的可行性及精度。结果表明，该方法能够提高层析结果的精度，与传统层析方法相比，该方法在均方根（root mean square，RMS）、水汽密度廓线和误差分布上均优于传统方法。

An Approach of Imposing Virtual Signals to Sophisticate Water Vapor Tomographic Model

The number of signal rays passing through a research area are often limited due to the geometric distribution of satellite constellations and receivers. To solve this issue, an approach is proposed that imposes virtual slant signals on the tomographic model. This approach increases the number of signal rays passing through a research area and. improves accuracy. An experiment tested the feasibility and accuracy of proposed approach by comparing with the results using Global Positioning System and meteorological data for 31 days in May, 2013, provided by Hong Kong Satellite Positioning Reference Station Network and those derived from radiosonde data. The Root Mean Square water vapor profile and error statistics for proposed method are all superior to that of traditional method. The experiment shows that the proposed approach can improve the accuracy of tomographic results.