【摘要】 针对GPS对中性大气折射延迟改正精度的要求,论述大气折射延迟模型应随测站和方向而异的必要性.在尚不能直接测定大气折射率的情况下,指出现有的各种改正模型不能达到预期精度要求的原因以及改正值对大气分布模型的依赖性.提出提高大气折射延迟改正精度的新方法:利用不同方位的天文大气折射值的测定数据,求解折射率差和映射函数的参数,建立随观测站和随方位而异的大气折射延迟改正模型.该方法的实施能在避免采用大气分布模型的情况下,把天顶延迟的改正精度提高到1mm以内,低地平高度角的折射延迟改正精度提高到厘米级,并且把截止高度角压缩到5°或更小.更多还原

【Abstract】 Aim at the requirement of GPS on correction precision of neutral atmospheric refraction delay,the paper expatiated the necessity that the refraction delay correction value should be different with the station and azimuth.In the instance of astronomic atmospheric refraction value can’t be directly determined,we point out that the current correction models depend on atmosphere distributing model,can’t arrive at the prospective precision and reduce cut-off angle in observation.The paper gave a new method for advancing the correction precision of refraction delay.It’s principle is: using the actual surveying datum of astronomical atmospheric refraction value which is from zenith to lower elevation angles along certain the azimuth in the station,and then,make certain the refractivity and parameters in the mapping function.In this way,correction model of atmospheric refraction delay can be constituted,which is different with the station and azimuth.In circumstances of non-adopting any atmospheric distributing model,the method may improve observational precision of lower elevation angles to centimeter’s magnitude,zenith delay’s precision to 1mm,and reduce cut-off angle to 5 degree or less.更多还原