LaserCom in UAS missions: benefits and operational aspects

Free Space Optical Communications (FSOC) is progressing continuously. With the successful in-orbit verification of a Laser Communication Terminal (LCT), the coherent homodyne BPSK scheme advanced to a standard for Free-Space Optical Communication (FSOC) which now prevails more and more. The LCT is located not only on satellites in Low Earth Orbit (LEO), with spacecrafts like ALPHASAT-TDP and the European Data Relay Satellite (EDRS) the LCT will also exist in Geosynchronous Orbit (GEO) in the near future. In other words, the LCT has reached its practical application. With existence of such space assets the time has come for other utilizations beyond that of establishing optical Inter-Satellite Links (ISL). Aeronautical applications, as for instance High Altitude Long Endurance (HALE) or Medium Altitude Long Endurance (MALE) Unmanned Aerial Systems (UAS) have to be addressed. Driving factors and advantages of FSOC in HALE/MALE UAS missions are highlighted. Numerous practice-related issues are described concerning the space segment, the aeronautical segment as well as the ground segment. The advantages for UAS missions are described resulting from the utilization of FSOC exclusively for wideband transmission of sensor data whereas vehicle Command and Control can be maintained as before via RF communication. Moreover, the paper discusses FSOC as enabler for the integration of air and space-based wideband Intelligence, Surveillance and Reconnaissance (ISR) systems into existent military command and control systems.