D. Ponchak, F. Templin, R. Jain, G. Sheffield and P. Taboso, "UAS CNS Architectures for Uncontrolled Airspace," Presentation at 2018 Integrated Communications, Navigation, Surveillance Conference (ICNS), Herndon, VA, 2018, pp. 1-35, INSPEC: 17843298, ISBN: 9781538656808, doi: 10.1109/ICNSURV.2018.8384921


This study introduces new Communications, Navigation and Surveillance (CNS) architectural concepts for the safe operation of Unmanned Air Systems (UAS) in the uncontrolled airspace. Uncontrolled airspace (Class G) constitutes those regions that do not overlap with controlled airspace domains (Class A-E), and are not monitored by Air Traffic Controllers (ATCs) and Airline Operation Controllers (AOCs) in the global Air Traffic Management (ATM) service. Small UAS (sUAS) that operate in this domain may be engaged in the services of law enforcement, parcel delivery, agricultural monitoring and any of the other multitudes of use cases envisioned for the coming age of autonomous vehicles. Each sUAS consists of zero or more remote pilots, one or more small Unmanned Aircraft (sUA) and any communications data link equipment needed to support safe operations. Operations of sUAS must support the principles and operating concepts articulated in the NASA Unmanned Air Traffic Management (UTM) vision.

sUAS are already entering into service in the National Airspace (NAS) through certification in the FAA Small Unmanned Aircraft Regulations for sUAs less than 55lbs, known as "Part 107". The maximum allowable altitude for the operation of Part 107-compliant sUAs is 400 feet above the ground, and higher if the sUA remains within 400 feet of a structure; the maximum velocity is 100mph. Part 107-compliant sUAS currently must be operated by remote pilots within visual line of sight (VLOS), but the UTM vision calls for both Beyond Visual Line of Sight (BVLOS) in the near future and eventually fully-autonomous sUAs. Clearly, therefore, regulations will need to continue to evolve in conjunction with technological advancements.

With the massive numbers of sUAs expected in the NAS in the coming years, the scale of the operational paradigm will be on the order of magnitude of the numbers of cars on the road, rather than on the order of the numbers of airplanes in controlled airspace. We, therefore, envision a UTM service that is designed with scale as the primary design point. At the same time, UTM ATCs should be able to monitor the worldwide map of sUAs to gain situational awareness and issue high-level ATC directives if necessary. For this, a large-scale communications network connecting each sUA to the UTM service will be necessary. Due to the opportunistic radio access connectivity expected for sUASs (e.g., connecting via any available 4G/5G cellular Internet service within range), we envision a worldwide service network layered over the global public Internet itself.

In this paper, we discuss the communication networks, communication data links, navigation and surveillance (CNS) considerations for sUASs operating within the UTM. We envision the UTM as providing a service for sUAS in very similar fashion as Internetworking services like "Waze" provide traffic congestion, navigation and surveillance situational awareness to ground domain vehicles. Also as part of the service, the UTM will provide each sUAS with an Internet Protocol version 6 (IPv6) address so that UTM ATCs can locate and communicate with the sUAS wherever it happens to be operating worldwide. For UTM datalinks, we first describe the datalink currently in use, including cellular. We then describe some upcoming standards that may be useful for sUAS. We also show how DSRC and its cellular extension C-V2X have a good potential for adoption in the uncontrolled airspace. In terms of surveillance, we have analyzed what the market is currently offering for both cooperative and non-cooperative systems, and present a series of potential systems to complement those currently available that would facilitate the implementation of an autonomous UTM.

This study builds on our earlier publications on UAS CNS considerations and requirements, as well as a UAS CNS architecture concept for large UAS operating in controlled airspace. We observe that the same requirements and architectures derived in those works have applicability within the UTM framework. We, therefore, consider the UAS CNS architecture concept for uncontrolled airspace according to the requirements for communications networks, communications data links, navigation and surveillance. The resultant CNS architecture concept provides guidance for the safe integration of sUAS in the NAS.

This work was only a presentation with an extended abstract (above).

Complete Presentation (36 slides) in Adobe Acrobat format.

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