摘要
ＧＰＳ系统是现阶段功能最全、精度最高的卫星导航系统，大气层对ＧＰＳ系统定位和定时的影响已成为一个不可忽略的重要因素．本文从广州地区两天各两个时刻的气象探空资料中分析了各个时刻高空中几个已知高度点的折射指数，然后用线性处理的办法得到了１７ｋｍ范围左右高空中折射指数的模型，大气指数模型与此模型相比较，几个点折射指数的均方差很小，最后用这两种模型分别计算两天各两个时刻大气层对ＧＰＳ信号在垂直传播时所引起的附加时间延迟，二者之差最大不大于０．３ｎｓ，用指数模型可基本反映广州地区大气层对ＧＰＳ信号传播时间延迟的影响。
Global Positioning System (GPS) is the satellite navigation system which is the most advanced at present. Atmosphere is one important factor which can' t be ignored in affecting GPS positioning and timing accuracy. According to the data obtained from radiosondes four times in two successive days,the refractivities of atmosphere have been obtained for some points of known altitude. Then,the model of refractivity have been obtained fromthese values of refrativity with linear treatment. From the Comparison of this model withthe exponential model, we discover that the mean square errors for the refractivities ofthese two models at known points are small. Finally, we calculate the delay caused by atmosphere with each model for the case that the GPS signal propagates perpendicularly,and the results show that the difference of time delay is not larger than 0. 3ns. There, forwe conclude that generally the atmospheric exponential modle can be adopted to treat theeffect of atmosphere on GPS signal propagation time delay in Guangzhou region.
出处
《陕西天文台台刊》
CSCD
1994年第A00期16-19,共4页
Publications of The Shaanxi Astronomical Observatiory
