Developing an Effective Optical Satellite Communications Architecture

Abstract

The recent emergence of optical satellite communications (SATCOM) offers several advantages over traditional radio frequency (RF) SATCOM capabilities. These include achieving higher bandwidths, minimizing the effects of jamming, providing low probabilities of detection and intercept (LPD/LPI), and requiring lower satellite size, weight, and power (SWaP). However, optical SATCOM capabilities have limitations that can make it undependable for certain uses such as in establishing satellite-to-ground links due to the effects of cloud cover. Clouds can completely absorb or refract optical signals and have the most detrimental effects on optical links passing through the Earth’s atmosphere. RF SATCOM offers a variety of advantages that optical SATCOM does not, including the ability to operate reliably through the atmosphere and broadcast over large regions, though the RF spectrum is becoming a scarce resource that is increasingly difficult to manage and share among competing users. As a disadvantage, optical satellite links are also difficult to acquire and maintain because of their narrow beam widths. This paper proposes four optical SATCOM architectures that can mitigate the cloud cover problem using Geostationary Earth Orbit (GEO) satellites, along with intermittent Medium Earth Orbit (MEO) or Low Earth Orbit (LEO) satellites, to improve link availability.