Session
Session 8: Frank J. Redd Student Competition
Abstract
Free space optical communication systems typically require receiving telescopes on the ground to be a co-located, high power, unmodulated laser transmitter to serve as a beacon for locating the ground station. Unfortunately, these lasers may be costly and subject to regulations on optical power and frequency of use, which would not apply to a non-coherent light source. A directed LED optical beacon for use with free-space laser communication downlink systems is designed, constructed, and tested. The beacon, consisting of an array of 80 green LEDs, produced 15.9 Watts of optical power at a peak wavelength of 528 nanometres with a beamwidth of 8.12 degrees FWHM. The beacon was tested at the Wallace Astrophysical Observatory in Westford, Massachusetts. On-orbit imaging was accomplished by an on-orbit Cubesat in collaboration with the Aerospace Corporation using a camera with a silicon CMOS detector and a 7.9 mm optical aperture. The LED beacon is easily identified in a series of 5 images taken by the CubeSat, demonstrating the viability of the use of a non-coherent LED arrays as optical communication uplink beacons.
Non-coherent LED Arrays as Ground Beacons for Small Satellite Optical Communications Systems
Free space optical communication systems typically require receiving telescopes on the ground to be a co-located, high power, unmodulated laser transmitter to serve as a beacon for locating the ground station. Unfortunately, these lasers may be costly and subject to regulations on optical power and frequency of use, which would not apply to a non-coherent light source. A directed LED optical beacon for use with free-space laser communication downlink systems is designed, constructed, and tested. The beacon, consisting of an array of 80 green LEDs, produced 15.9 Watts of optical power at a peak wavelength of 528 nanometres with a beamwidth of 8.12 degrees FWHM. The beacon was tested at the Wallace Astrophysical Observatory in Westford, Massachusetts. On-orbit imaging was accomplished by an on-orbit Cubesat in collaboration with the Aerospace Corporation using a camera with a silicon CMOS detector and a 7.9 mm optical aperture. The LED beacon is easily identified in a series of 5 images taken by the CubeSat, demonstrating the viability of the use of a non-coherent LED arrays as optical communication uplink beacons.
