GPS资料分析中大气折射水平梯度的估计

THE ESTIMATION OF ATMOSPHERIC HORIZONTAL REFRACTIVITY GMDIENTS IN THE ANALYSIS OF GPS DATA

应用参数估计方法，由GPS实测资料估计了大气折射的水平梯度，得到了我国7个GPS站的大气折射水平梯度的初步结果。结果表明，上海和武汉两个站的水平梯度呈现快速时间变化特性。当卫星的截止高度角取为15°时，水平梯度对7个站的对流层天顶延迟的影响均小于1cm。同时也讨论了大气折射水平梯度对GPS相对定位的影响，当在平差中增加水平梯度作为待估参数时，各基线及其分量的重复率有一定程度的提高。

Using the pararneter estimaion methods, the atmospheric horizontal rehativity gradients at 7 GPS stations in China are estimaed. The results show that the horizontal gradients in Shanghai and Wuhan stations present rapid time-varying characteristic.When the cut-off elevation angle of satellites are taken as 15°, the effects of horizontal gradients on tropospheric zenith delay of 7 stations are all less than 1cm.The effects of horizontal guadients on GPS relative positioning are also discussed. The daily repeatabilihes of baseline compoents and length are improved when atmospheric horizontal gradients are estimaed simultaneously with other parametrs in data analysis.