Optimization trades for a multi-aperture laser communications ground terminal

Abstract

The most important single attribute of a Laser Communications Ground Station is the receiver aperture area to maximize the received signal and hence signal-to-noise ratio (SNR). However, the larger the aperture, the greater the negative effects imparted by the atmosphere on the signal, thus causing signal fading and negatively effecting SNR. To mitigate the atmospheric effects of a large aperture, adaptive optics are needed. It has been previously proposed to use a number of smaller telescopes with only simpler tip/tilt correction with non-coherent power combining as a lower cost way to achieve the benefits of a large signal energy capture area without the significantly higher cost of a single large telescope with adaptive optics. This paper will investigate optimal trades of the number and size of individual telescopes to achieve a desired signal capture area of a single large telescope with adaptive optics. The cost of the telescopes, extra beam combining, and especially the atmospheric effects as a function of the size of a telescope with only tip/tilt correction will be addressed.