Abstract

1. BACKGROUND

The resolution achieved in ground-based space-object imaging is usually limited by turbulence-induced aberrations. Although adaptive-optics systems designed to eliminate phase aberrations introduced by atmospheric turbulence correct a large portion of these aberrations, the correction is never perfect. There are several sources of residual aberrations that degrade the imagery: imperfect wavefront sensing (particularly in low light level situations), the time lag between sensing and correction (which allows for evolution of the atmosphere and is a particular problem when slewing to track an earth-orbiting space object), and deformable-mirror fitting errors. There are also scenarios in which adaptive-optics compensation is intermittent, degraded, or simply unavailable. For instance, when tracking an artificial satellite at a sufficiently high slew rate, the performance of the adaptive optics loop can degrade and fluctuate to a degree which severely limits the resolution in the images. Furthermore, a pure post-detection capability insures the continuing availability of fine-resolution images, even during adaptive-optics down time owing to routine maintenance or temporary system failure. Therefore, post-detection reconstruction methods provide an important complement to and backup for pre-detection correction.

© 1996 Optical Society of America