Open AccessEstimability analysis of geodetic, astrometric and geodynamical quantities in very long baseline interferometry
Author(s) -
Dermanis A.,
Grafarend E.
Publication year - 1981
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1981.tb02657.x
Subject(s) - geodetic datum , geodesy , interferometry , baseline (sea) , astrometry , geology , very long baseline interferometry , remote sensing , computer science , astronomy , physics , computer vision , stars , oceanography
Summary. Within the framework of Newtonian kinematics VLBI observations are analysed with respect to estimability of geodetic and astrometric quantities. An Earth model of either rigid or deformable type is designed; instrumental clock offsets and clock drifts are included. Observational patterns are studied in all detail reviewed in seven tables. Appendix A is an introduction to the set‐up of the observational model for a deformable Earth both in terms of coordinate‐free and coordinate‐related geometry. Appendix B is a study of the invariance characteristics of VLBI observations. Interrelations of three fundamental quantities, length unit, time unit and velocity of light are discussed. An overall result of an Earth model of deformable type is the need of simultaneous observations to more than one source; VLBI time delay observations cannot distinguish between secular changes of network size (expansion or shrinking) and a common secular drift (deceleration or acceleration) of clocks used.