SCaN Optical Link Assessment Tool Version 3(LEW-19463-1)

A calculation procedure has been designed and implemented in software that enables the specification and design of a space-based optical communications system. The resulting optical link budget essentially accounts for the communication power flow through the entire optical communications channel from the transmitter to the receiver and yields design specifications for the optical system necessary to assure reliable data transmission with desired operational metrics such as data rate, link margin, etc. The link assessment tool takes into account all the sources of deleterious noise that enters into the communications process such as electronically generated noise in the optical detector and stray optical irradiance from external sources. The link budget has the capability of being interfaced with the orbital element calculations of the Satellite Tool Kit (STK) to allow the dynamic description and evolution of optical link operation from any space-borne satellite within the solar system to and from the earth. The current version implements PPM and DPSK modulation types that can use PIN, APD, or nanowire optical detectors in the presence of atmospheric turbulence. Coded and un-coded link power margins are provided. This version of the tool also has the ability 1) to solve for prevailing potential data rates given a desired optical power link margin and 2) treat the spatial separations of optical link transmitter and receiver within thefirst Fresnel zone.