深空干涉测量对流层经典模型改进

Improvement of classical tropospheric model for deep space interferometry

对流层延迟修正误差是深空干涉测量的重要误差源之一。通过修正对流层经典天顶延迟模型和Niell映射函数NMF(Niell Mapping Function)构建了一种高精度区域对流层延迟模型。首先,结合我国深空网喀什深空站对流层延迟实测数据,对Saastamoinen模型的适用性进行分析,通过线性最小二乘拟合修正天顶干延迟参数,模型精度相对改善29.6%;然后,针对NMF低仰角情况下映射偏差较大的问题,构建偏差函数模型,显著改善了低仰角下的映射性能,经实测数据验证:仰角在0°~30°时,对流层延迟模型偏差相对改善约30%。改进后的对流层区域模型估计精度高,可为我国深空干涉测量对流层延迟修正提供参考。

Tropospheric delay correction error is one of the important error sources of deep space interferometry.In this paper,a high-precision regional tropospheric delay model is constructed by modifying the classical tropospheric zenith delay model and Niell Mapping Function(NMF).Firstly,the applicability of Saastamoinen model was analyzed based on the tropospheric delay data measured at Kashi Deep Space Station of China's Deep Space Network.The zenith stem delay parameters were modified by linear least square fitting,and the model accuracy was improved by 29.6%.Then,aiming at the problem of large mapping deviation of NMF at low elevation angle,a deviation function model was constructed,which significantly improved the mapping performance at low elevation angle.The measured data verified that the tropospheric delay model deviation was relatively improved by about 30%when elevation angle was 0°~30°.The tropospheric regional model proposed in this paper has high estimation accuracy and can provide reference for tropospheric delay correction in deep space interferometry in China.