导航系统中的对流层延迟效应分析

Analysis of the Troposphere Delay Effect in Navigation System

提高卫星导航系统的定位精度一直是该领域科研人员的努力方向之一,其中作为影响卫星系统定位精度误差源的对流层延迟改正也一直是研究的重点。瞄准我国自主研制的北斗卫星系统中的对流层延迟问题,首先根据引起对流层折射误差的两种电波传播效应,即大气引起电波传播速度的减慢和引起电波射线的弯曲,分析了这两种效应在卫星定位中产生的折射误差情况。其次通过典型的实测探空数据和射线描迹法计算折射误差,得到了两种效应对对流层折射误差的贡献。证明了在卫星高度角大于5°时可以忽略电波射线弯曲引起的折射误差,在进行对流层延迟改正中只需考虑大气折射率引起电波速度减慢效应即可。但是在卫星高度角小于5°时必须考虑两种电波传播效应引起的折射误差。

Improving the positioning accuracy of satellite navigation system has always been one of the efforts of researchers in the field,and the tropospheric delay correction as the error source of satellite system positioning accuracy has always been the focus of the study.Aiming at the problem of tropospheric delay in the BeiDou satellite system developed by our country,firstly,according to the two kinds of radio propagation effects caused by the tropospheric refraction error,that is,the slowdown of the wave propagation velocity caused by the atmosphere and the bending of the radio waves,The error of refraction caused by satellite positioning.Secondly,the refractive error is calculated by the typical measured sounding data and ray tracing method,and the contribution of the two effects to the tropospheric refraction error is obtained.It is proved that the refraction error caused by the bending of the radio wave can be neglected when the satellite height angle is greater than 5 degrees,and the effect of the wave velocity slowing effect can be avoided only by considering the atmospheric refractive index in the tropospheric delay correction.However,when the satellite elevation angle is less than 5 degrees,two kinds of radio propagation effects must be considered to avoid the refraction error.