Compute Time for Single Conjugate AO Simulations
Compute time for single conjugate adaptive optics simulations on a 2.4
GHz Pentium 4. These simulations were performed using a six layer
Cerro Pachon atmospheric turbulence model. A fixed subaperture size
of 35.7 cm was used, and the number of subapertures across the pupil
ranged 10 to 84 for aperture diameters from 3.6 to 30 meters.
Monochromatic radiation at .5 microns was used for wavefront sensing,
and at 2.2 microns to simulate the science image. The science image
was calculated over a 4 arcsecond field of view and was oversampled by
a factor of 8 relative to Nyquist. The left panel shows the total
time required per iteration of the control loop. In these
simulations, wavefronts and atmospheric screens were sampled at a
pixel scale of 2 cm and were propagated through the atmosphere using a
geometric propagator. Also shown are the largest three computational
components: propagation through the lenslet array, propagation through
the atmosphere, and propagation to the far field. With the field size
in arcseconds and the sampling defined relative to Nyquist, the last
component is increasing with aperture diameter as the diffraction
limit decreases. The central panel shows the total simulation time
per iteration of the control loop for pixel scales between 1 and 4 cm.
Two curves are plotted for each pixel scale, corresponding to
geometric and diffractive propagation through the atmosphere. The
right panel shows the time required to compute the least squares
reconstructor and the space required for its storage.