title: Optimization of star-oriented and layer-oriented wavefront sensing concepts for ground layer adaptive optics.
abstract: Multiconjugate adaptive optics is one of the major challenges in adaptive optics. It requires the measurement of the volumic distribution of the turbulence. Two wavefront sensing (WFS) concepts have been proposed to perform the wavefront analysis for such systems: the star-oriented and layer-oriented approaches. We give a performance analysis and a comparison of these two concepts in the framework of the simplest of the multi-guide-star adaptive optics systems, that is, ground layer adaptive optics. A phase-related criterion is proposed to assess analytically the performance of both concepts. This study highlights the main advantages and drawbacks of each WFS concept and shows how it is possible to optimize the concepts with respect to the signal to noise ratio on the phase measurement. A comparison of their optimized versions is provided and shows that one can expect very similar performance with the two optimized concepts.
authors.affiliation: Office National d'Etudes et de Recherches Aérospatiales, BP 72, 92322 Châtillon, France. magalie.nicolle@onera.fr
authors.forename: Magalie
authors.initials: M
authors.lastname: Nicolle
authors.forename: Thierry
authors.initials: T
authors.lastname: Fusco
authors.forename: Vincent
authors.initials: V
authors.lastname: Michau
authors.forename: Gérard
authors.initials: G
authors.lastname: Rousset
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Beuzit