Summary: The task First Look Preprocessing provides a daily check of the functioning of Gaia on the basis of the scientific measurements of the satellite. Within this task, the Ring Solution is a special algorithm with some resemblances to the Great-Circle Reduction of ESA's astrometry satellite HIPPARCOS. The observed stars are connected by their astrometric, attitude and calibration parameters so they form a ring on the celestial sphere. Here, the special interest of the Ring Solution is the estimability and the accuracy of an appropriate set of parameters describing all quantities in question.
 

Bibtex entry for this abstract:

@UNPUBLISHED{LL:GAIA-ARI-BST-001,
author = {C.~Bernstein and U.~Bastian and S.~Hirte},
title={{F}irst look - description of the ring solution},
institution={Astronomisches Rechen-Institut, Heidelberg (part of ZAH, Zentrum fuer Astronomie, Heidelberg)},
year={2005},
month={November},
url={http://www.rssd.esa.int/doc_fetch.php?id=381198},
note={GAIA-ARI_BST-001},
type={Technical note}
}