SBIR-STTR Award

Communication with miniature satellites presents a significant challenge, since their small size and limited power generation conflict with the need for long-distance communication links. Today’s advanced sensors have driven the bar even higher by requiring increased bandwidths that can only be satisfied by optical communication. Conventional free-space optical (FSO) communication, however, typically requires some form of mechanical beam steering, which is expensive, heavy and bulky, and can also upset the position of an orbiting satellite. We propose to develop a passive optical communication system that eliminates the need for tracking systems on the satellite. To accomplish this, we will make use of our Smart Retroreflector[TM], which can provide passive communication over an extremely wide field of regard. We will examine both conventional and MOEMS versions of this technology and will also investigate the use of optical gain media to amplify the communication signals. Hardware experiments will be performed to evaluate each technique’s feasibility, and the most effective technique will be chosen for further development and flight testing in Phase II. Our considerable laboratory experience and proven expertise in FSO communication place us in a unique position to address all relevant issues for this program, from link performance to marketing strategies.

Benefits:
In addition to the benefits of enabling low-cost satellites to be flown in great numbers, thereby advancing the state of science for space platforms, low-cost passive communication systems and components can be applied to a great number of applications. Just a few of the more prominent commercial, government, and operational military applications that could benefit from this and subsequent programs include truly high-speed, last-mile internet connectivity, Search and Rescue (SAR), robotic control, automated aircraft landing guidance, and auto-alignment of optical systems. The use of a low-power optical communicator will also enable accurate, covert combat identification to prevent 'friendly fire' incidents. It can also be used as a transponder ID system for ships, vehicles, cargo and aircraft that does not contribute to the increasingly problematic 'RF clutter' that is present in many areas. Farming and land maintenance will become more automated and self-coordinating. Homeland, harbor and military base security will be improved through enhanced surveillance data transmission capabilities by permitting large numbers of low-power/low-maintenance sensors to be deployed as needed.

Keywords:
free-space optics, satellite, communication, security, identification friend or foe, wireless, network, eye-safe

There are many uses for miniature satellites, from Intelligence, Surveillance and Reconnaissance (ISR) to communications relays and platforms for scientific experiments. The small size and inexpensive nature of these platforms permits a larger number of satellites to be launched from one vehicle, and also increases the total functionality of our space assets by encouraging earlier launches of leading edge technologies and devices. Communication with miniature satellites remains a challenge, however, since their small size and limited power generation conflict with their need for long-distance communication links. We propose to design, fabricate and test an Amplified Retroreflecting Optical Communication (AROC) system that 1) eliminates the need for a precision tracking system on the satellite, 2) eliminates the need for a satellite-mounted, high-power laser transmitter, 3) significantly reduces the pointing accuracy requirements of the satellite attitude control system, and 4) reduces the optical power requirements from the ground station. The AROC comprises a first-ever bi-directional, Mbps communication technique that amplifies the optical signal so that it has sufficient strength to be received by a ground station, while simultaneously permitting full-duplex high-data-rate communication with satellites in low-earth orbit (LEO).

Keywords:
FREE-SPACE OPTICS, COMMUNICATION, SATELLITE, LEO, SPACE, COVERT, RETROREFLECTOR, LASER