中文摘要：

精密单点定位（PPP）精度因子分析对于坐标和对流层估计精度预测具有重要意义。本文利用IGS提供的精密星历文件计算并分析了不同对流层映射函数对精密单点定位中对流层天顶方向湿延迟估计的精度因子的影响以及当对流层延迟能够精确用模型改正时精密单点定位精度因子的大小。采用Chao映射函数模型估计出的对流层天顶方向湿延迟的精度最高而使用Ifadis映射函数模型估计出的对流层天顶方向湿延迟的精度最低。当对流层延迟能用模型改正（四参数）时,精密单点定位的位置精度因子和钟差精度因子将显著减小,其中接收机钟差精度因子减小最明显,Y方向精度因子次之。

英文摘要：

The dilution of precision analysis of precise point position is significant for prediction of coordinate and troposphere estimation.In this paper,the effect of different tropospheric mapping function to the PPP dilution of precision is investigated and the magnitude of the PPP dilution of precision is analyzed if the tropospheric delay can be accurately modeled.When the zenith tropospheric wet delay is estimated,the most precise model is Chao mapping function and the Ifadis mapping function is the most imprecise.If the tropospheric delay can be modeled,the dilution of precision about position and receiver clock error would significantly reduce,and the precision of receiver clock error is improved the most obviously.