AOB-1 is an Adaptive Optics (AO) facility currently designed to feed the Gemini infrared Multi Object Spectro-
graph (GIRMOS) on the GEMINI North 8m class telescope located in Hawaii. This AO system will be made of two
AO modes. A laser tomography AO (LTAO) mode using 4 LGS (laser guide stars) and [1-3] NGS (natural guide
stars) for high performance over a narrow field of view (a few arcsec). The LTAO reconstruction will benefit from
the most recent developments in the field, such as the super-resolution concept for the multi-LGS tomographic
system, the calibration and optimization of the system on the sky, etc. The system will also operate in Ground
Layer Adaptive Optics (GLAO) mode providing a robust solution for homogeneous partial AO correction over a
wide 2' FOV. This last mode will also be used as a first step of a MOAO (Multi-object adaptive optics) mode
integrated in the GIRMOS instrument. Both GLAO and LTAO modes are optimized to provide the best possible
sky coverage, up to 60% at the North Galactic Pole. Finally, the project has been designed from day one as a
fast-track, cost effective project, aiming to provide a first scientific light on the telescope by 2027 at the latest,
with a good balance of innovative and creative concepts combined with standard and well controlled components
and solutions. In this paper, we will present the innovative Phase A concepts, design and performance analysis of
the two AO modes (LTAO and GLAO) of the AOB-1 project.