A model of geometric delay in Space VLBI

A model which includes the relativistic effect is derived that can be applied to space very long baseline interferometry （SVLBI） while taking observations of sources at infinite distance. In SVLBI, where one station is on a spacecraft, the length of the baseline and the orbiting station＇s maximum sp...

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Bibliographic Details
Published inResearch in astronomy and astrophysics Vol. 14; no. 8; pp. 1029 - 1036
Main Authors Liao, Shi-Long, Tang, Zheng-Hong, Qi, Zhao-Xiang
Format Journal Article
LanguageEnglish
Published 01.08.2014
Subjects
Astronomy
Correlators
Delay
Interferometers
Intervals
Polynomials
Spacecraft
Stations
几何
多项式拟合
延迟模型
时间间隔
椭圆轨道
甚长基线干涉测量
相对论效应
空间VLBI
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Summary:A model which includes the relativistic effect is derived that can be applied to space very long baseline interferometry （SVLBI） while taking observations of sources at infinite distance. In SVLBI, where one station is on a spacecraft, the length of the baseline and the orbiting station＇s maximum speed in an elliptical orbit around the Earth is much larger than the ground-based VLBI, which leads to a larger delay and higher delay rate. The delay models inside VLBI correlators are usually expressed as fifth-order polynomials during a limited time interval, which are evaluated by firmware in the correlator and track delays in the interferometer over the limited time interval. The higher SVLBI delay rate requires more accurate polynomial fitting and evaluation, as well as more frequent model updates.
Bibliography:A model which includes the relativistic effect is derived that can be applied to space very long baseline interferometry （SVLBI） while taking observations of sources at infinite distance. In SVLBI, where one station is on a spacecraft, the length of the baseline and the orbiting station＇s maximum speed in an elliptical orbit around the Earth is much larger than the ground-based VLBI, which leads to a larger delay and higher delay rate. The delay models inside VLBI correlators are usually expressed as fifth-order polynomials during a limited time interval, which are evaluated by firmware in the correlator and track delays in the interferometer over the limited time interval. The higher SVLBI delay rate requires more accurate polynomial fitting and evaluation, as well as more frequent model updates.
astrometry -- interferometric -- analytical
11-5721/P
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1674-4527
2397-6209
DOI:10.1088/1674-4527/14/8/013