Unmanned aerial vehicles: Communications challenges and future aerial networking

The use of unmanned aerial vehicles (UAVs) will grow rapidly in the next decade. These remotely piloted or preprogrammed aircraft are envisioned for applications in numerous civil settings, including industrial monitoring, scientific data gathering, agriculture, public safety, and search and rescue. Many other applications - presently unforeseen - will inevitably also arise. These vehicles, also known as unmanned aerial systems (UAS), and by the unfortunate misnomer of "drones," must be integrated into the national airspace system in the United States, and into the airspace worldwide. A natural concern in the use of UAS is safety, and this has direct implications for the control and non-payload communication (CNPC) systems that must be used to operate UAS. Similarly, navigation and surveillance functions must be made more reliable and more accurate. Because of these factors, many UAS research, development, testing, and standardization efforts are underway by governments, industries, and academia. Despite the fact that piloted civil aircraft have been flying safely for decades, UAS CNPC presents distinct new challenges in the form of different flight profiles, e.g., low-elevation flights and more high-dynamic maneuvers; wider required bandwidths, e.g., for video; and different ground site characteristics such as locations in cluttered areas and lower elevation antennas. In this paper we first review our work for NASA on the characterization of the UAS air-ground channel, and our ongoing efforts in evaluation of radio technologies and UAS networking performance. We highlight related significant work in the area and identify the newest challenges in UAS communications and networking. The final part of the paper presents information on trends and opportunities in the vibrant field of UAS communications and networking.