The steps in integrating HOMER

• April 2007: Definition of the definitive architecture of the test bench

• July - August 2007: Calibration of DM1 and the WFS and imaging cameras. For the cameras, the tests were run without water cooling.
  

• September 2007: First AO loop closure with DM1. The optics of the test bench not yet having arrived, they were replaced with optics having characteristics as close as possible to reality.

• October 2007: Closure of the AO loop with the definitive optics. DM2 is then replaced by a flat mirror with the same diameter.

• November - December 2007: Closure of the AO loop in the presence of turbulence:

- Turbulence applied by DM1 with additive voltages and correction by DM1
- Turbulence applied by DM2 with additive voltages (DM2 controlled by the PC) and correction by DM1

• January 2008: Control of DM2 by the RTC. AO loop closed with DM2.


• April - May 2008: Closure of the GLAO [1] (Ground Layer Adaptive Optics) loop, correction with 1 mirror, and in MCAO [2], correction with 2 mirrors and analysis in 3 directions. First experimental results on the test bench.
  


• June 2008: Presentation of the results obtained with HOMER at the SPIE conference in Marseille, 23rd to 28th June 2008. Paper 7015-152 "Optimization of MCAO performance: experimental results on the ONERA laboratory MCAO bench".

• August 2008: Implementation of the Linear Quadratic Gaussian [3] (LQG) control law on HOMER

- Closure of the conventional AO loop with a direction of analysis at the center and a correction mirror in the pupil plane. Turbulence on one layer in the pupil plane,
- Closure of the off-axis AO loop with a direction of analysis at the center of the field and mirror correction in the pupil plane in another direction. Turbulence on a layer situated at altitude,
- Closure of the TAO [4] loop with 3 directions of analysis, correction at the center of the field with the mirror in the pupil plane. Turbulence on two layers, one in the pupil plane, the other at altitude. 

• Septembre 2009 : Implementation of the turbulent module, son which 3 turbulent layers are installed, one in the pupil, the 2 other ones are conjugated with altitude.  In these realistic conditions of turbulence, closure of the conventional AO loop and TAO with LQG control law with 3 directions of analysis, correction at the center of the field with the mirror in the pupil plane.

_______________________________________________________

[1] GLAO: Ground Layer Adaptive Optics: Wide field AO system comprising several WFS and a pupil conjugate deformable mirror. It is used to correct the average turbulence in a wide field. The performance of such a system is not very high but is homogeneous in the field.

[2] MCAO:Multi-Conjugate Adaptive Optics: Wide field AO system comprising several WFSs to analyze the volume of turbulence and several DMs to correct the turbulence in a wide field.

[4] TAO:Tomography Adaptive Optics: AO system used to analyze and reconstruct the turbulent volume in different directions of the field then to correct the turbulence in a single direction of the field with a DM in the pupil plane.