Hyper-Spectral Communications, Networking & ATM as Foundation for Safe and Efficient Future Flight: Transcending Aviation Operational Limitations with Diverse and Secure Multi-Band, Multi-Mode, mmWave (HSCNA)

The HSCNA project goals were to contribute to the NASA Aeronautics Research Mission Directorate's Strategic Thrust 1—Safe, Efficient Growth in Global Operations—by investigating techniques and developing technologies that will significantly improve aviation link communication and networking performance, for air-ground and airport applications. The HSCNA project closed out in December 2021 after successfully demonstrating multiple technologies. Some of the project’s major achievements are:

1. Produced a thorough draft Concept of Operations for future (~2035) ATM. This document assimilated material from multiple key organizations, including NASA and the FAA. The Concept of Operations focuses on communications, navigation, and surveillance (CNS) for Air Traffic Management (ATM) and helped form a foundation for all remaining project tasks.
2. Extended the foundation via compilation of a comprehensive review of existing and planned CNS systems. This included current and planned aviation systems such as Very High Frequency (VHF) digital link, Aeronautical Mobile Airport Communication System, and L-band Digital Aeronautical Communications System (LDACS), commercial (e.g., cellular, Wi-Fi) wireless systems, satellite systems, and other potential technologies. This review identified gaps, some of which were directly addressed by the project. The project also identified “far future” technologies whose deployment would yield ample benefits (e.g., free-space optical).
3. Designed two new air interface waveforms for air-to-ground (AG) communications: non-linear chirps and filter bank multicarrier (FBMC). FBMC offers better spectral efficiency, and better robustness to high-power adjacent channel interference (from distance measurement equipment, DME). The project developed FBMC prototype radios and have tested in the laboratory and in terrestrial mobile settings, and flight tests to come later with the South Carolina Civil Air patrol. The project presented the FBMC designs to the ICAO standards committee working on LDACS.
4. Worked on mmWave systems for mostly short-range applications offering extremely large data rates via the wide bandwidths available in these frequency ranges. The propagation channel presents significant challenges; hence much of the work was conducted in measuring and modeling wireless channel path loss, multipath distortion and fading, obstruction and material attenuation, and channel dynamics. The aim was indoor and outdoor links for airport applications. The combined efforts covered a frequency range from 5 GHz to 140 GHz—a larger band than any other existing team. The project also developed more accurate models for the significant tropospheric attenuation that can occur in these bands, as well as multiple novel mmWave antenna designs, mmWave networking, resource allocation, and investigated machine learning techniques for future dense networks.
5. Developed schemes for the accurate detection of small unmanned aerial vehicles (UAVs) – in this work the project investigated use of radio emissions from small UAVs themselves and how these could be used to accurately identify (classify) specific UAV models at a distance. The project also investigated the use of radars for this purpose, studying and testing with 15 GHz systems, and quantifying the radar cross sections of over a dozen popular drones. Networks of sensors were also studied for their superior ability to aggregate information from multiple locations to increase drone detection probability. Part of this work also studied tracking algorithms for small UAVs where applied machine learning was utilized successfully.
6. Development of advanced ATM simulations, laying the groundwork to incorporate all the findings and techniques of the project tasks. This simulation considers multiple aircraft types as well as multiple air traffic services and phases of flight.

With approximately 150 refereed publications, 7 or more patent applications, multiple presentations, book chapters, work with industry and standards organizations, and over two dozen graduated students, this project has been a great success.