Adaptive Optics for Space Situational Awareness
We are developing and will commission a space debris and satellite imaging system in New Zealand to improve image resolution of Earth orbiting objects. Our simplified, low-cost approach is based on restricting possible regions where orbiting satellites and large space debris objects pass through the Galactic plane, where they can be detected within a background of natural stars. We will use a modular, wide-field adaptive optics (AO) system to estimate the spatially variant point spread function (SVPSF) using multiple natural guide stars (NGSs) to compensate for atmospheric turbulence over a wide field-of-view (FoV). To achieve this, our custom designed geometric wavefront sensor will provide estimates of phase perturbations from three or more isoplanatic patches. A combination of closed- and open-loop adaptive optics is employed. The closed-loop system will use a bright NGS for low-order aberration reduction using a Shack Hartmann wavefront sensor for correcting the optical path using a tip/tilt mirror system in real-time. Our open-loop system will estimate wavefronts from three of more natural stars and use atmospheric tomography to determine the SVPSF, off-line. From the SVPSF estimate, deconvolution from wavefront sensing is used to remove high-order aberrations fast moving target objects that will be imaged using a separate detector, synchronised with our AO cameras. A model for this hybrid AO system is described in this talk and its implementation will provide a platform to test novel methods for system refinement.
About the talk
Univ. de Canterbury, New Zealand