摘要
太阳引力场效应对高精度VLBI时延测量有较大影响。本文比较了两种改正太阳引力场效应的计算方法——基于太阳引力偏折的方法和较差光行时方法,并由此得到结论:引力偏折与较差光行时是两个不同的概念;它们两者对VLBI时延测量的影响的量级相同,但相差一个主项,即引力场中电磁波速度大小的变化引起的附加时延;另外二者还相差一些小项。
In the solar gravitational field, both of the propagation direction and velocity of radio signal from a radio source could be changed, also both of the variations will cause the extra-delay in VLBI observation. In astrometry/geometry VLBI software, the evaluations of the solar gravitational effects were based on the variation of apparent position or on the differential 'light-time.'After comparison it must be pointed out that the gravitational deflection and differential'light-time'are basically different concepts. Any way, for computing gravitational effects in processing VLBI data, the principal difference between the deflection method and differential 'light-time' method is caused only by the variation of the velocity of radio signal passing through the solar gravitational field. The values of τgr, τgn and Δτgrav have same order of magnitude.
出处
《中国科学院上海天文台年刊》
1993年第14期222-226,共5页
Annals Shanghai Astronomical Observatory Chinese Academy of Sciences
关键词
太阳引力场
甚长基线干涉测量
电磁波
时延
Gravitational field-Solar gravitational field-Very Long Baseline Inte-r ferometry (VLBI)
