Citation
Abstract
Deep space optical communications is an important component of the NASA roadmap, with the potential for greater data-rates and greater reach for both robotic and human missions in the future. The baselined signaling format for optical deep space communications is pulse-position modulation (PPM), detected directly with a large aperture ground-based optical receiver. While this design is perfectly adequate for low background reception, as encountered during nighttime operation, photon-counting receiver performance degrades significantly during the day when turbulence distorts the optical phase-front causing the receiver to open up its field-of-view (FOV) to collect the available signal energy, thus letting in more background photons that interfere with photon-counting detection. A plausible approach to improving daytime optical reception is to use Adaptive Optics (AO) to reconstruct the optical fields, enabling operation with much narrower FOV and thus reducing background interference. A key component of the AO system is the Shack-Hartmann Wavefront Sensor, initially developed for astronomical imaging applications, which however is very sensitive to daytime background interference. Here we propose and evaluate a Coherent Wavefront Sensor concept that virtually eliminates background interference, and in addition improves detection performance in high background environments, thus enabling efficient daytime optical communications over the photon-starved deep-space optical channel.
Details
- Volume
- 42-218
- Published
- August 15, 2019
- Pages
- 1–19
- File Size
- 989 KB