地基GPS可降水量反演的测站相关性研究

Research on correlation of observation station in inverting of precipitable water vapor based on ground-based GPS

地基GPS反演可降水量的基本原理是通过监测观测站上空天顶方向水汽总量,将观测中的“观测噪声”转变为需要的大气参数,而地基GPS局域网中相近测站的卫星高度角几乎相同,受到的大气延迟量则几近相同,因此局域网中的相邻测站上空的天顶延迟量有很强的相关性,而利用GAMIT等软件解算出的大气可降水量虽能消除相关性,却会呈现一定的系统偏差,为了获得测站上空的绝对大气可降水量,通过引入网外长基线IGS参考站的方法消除系统偏差,并得出结论只要引入2～3个网外IGS参考站就可确保测站的绝对可降水量精度.

The basic principle of inverting precipitalbe water vapor using ground-based GPS data is to transform＂observation noise＂into atmospheric parameters needed by monitoring the total amount of water vapor in zenith direction above the observatory,but the elevation angles of satellites are almost the same in the adjacent observation station in LAN of groundbased GPS and its atmospheric delay is nearly the same, so the delay over adjacent observation station of LAN has a strong correlation, we can eliminate the correlation by using software GAMIT, but it brings in system error. In order to get absolute atmospheric precipitation over the station,this paper brings in 2-3 IGS reference stations which is longbase line outside of the network to eliminate the system error, finally it concludes that we can ensure the accuracy of absolute precipitation over adjacent observation station by bringing in 2-3 IGS reference stations.