UAS Integration into National Airspace System

Introduction
The Next Generation Air Transportation System (NextGen) is considered a comprehensive overhaul of the National Airspace System (NAS) across U.S. that the Federal Aviation Administration (FAA), in collaboration with other agencies, are undertaking (Paczan, Cooper, & Zakrzewski, 2012). There are three main goals of what NextGen strives to achieve. Firstly, it aims to enhance navigation so that air traffic routing can be more efficient and allow more air traffic in the same airspace while reducing fuel consumption and carbon emissions. Secondly, it allows enhanced collision avoidance mechanisms such that every aircraft knows the location of each other in space to be able to avoid colliding into each other. Finally, there will be better digital data communications between aircraft and ATC systems (Goyer, 2015). Initiated in 2004, NextGen program will cost an estimated $40b and is expected to take years of air traffic system modernization that will extend at least 25 years into the future (Houston, 2016).

Foundation of NextGen
Forming the foundation of NextGen is the Automatic Dependent Surveillance Broadcast (ADS-B) technology that is made compulsory for all air traffic users in controlled airspace starting 2020 according to 14 CFR 91.225 and 14 CFR 91.227 (AOPA, 2015). The main purpose of ADS-B is to provide better aircraft location information than traditional radar systems to air traffic controllers. The system will enable continuous and almost real-time broadcasting of aircraft position information through the use of GPS satellite signals. An ADS-B enabled aircraft will be able to retrieve GPS data and other avionics data from its sensors to create a precise location, speed, altitude, etc. to ATC and other participating aircraft, thereby enhancing situational awareness of airspace users. ADS-B has two functions namely ADS-B Out, and ADS-B In. ADS-B Out will be the function that is mandatory for all aircraft in most controlled airspace. Airborne systems equipped with ADS-B Out will transmit its own identification, altitude, airspeed and direction to ATC and surrounding aircraft. ADS-B In, on the other hand, will receive information from other aircraft ADS-B Out and display the information.

How will NextGen affect UAS
The increasing role of UAS in applications such as search and rescue, weather monitoring, agricultural applications, military training, etc. has led to the proliferation of UAS today. However, because there is a lack of common understanding of the requirements to operate UAS safely in NAS, the continued expansion of commercial UAS operations has been inhibited (JPDO, 2012). The planning and architecture of NextGen did not clearly define the introduction of UAS. However, in the roadmap to integrate civil UAS into NAS by DOT (2013), its long term activities are consistent with Joint Planning and Development Office (JPDO) concept and vision of NextGen. The roadmap specifically states the requirement for UAS operations to continue evolving based on NextGen requirements.
Due to the nature of current UAS technology, such as the sensory limitations, it will continue to remain a human factor challenge to provide intuitive traffic information to enhance situational awareness of UAS pilots. Nevertheless, UAS operations can still benefit from ADS-B Out when installed. The technology will allow UAS to be visible to ATC and other suitably equipped airspace user. UAS that are equipped with transponders and traffic collision and avoidance system (TCAS) will also be visible to other users so that they can receive warnings and perform any necessary collision avoidance maneuvers. Therefore, in any inadvertent scenarios of problematic command and control links between ground control stations (GCS) and UAS, the ADS-B communication link, which runs on a different frequency, can still be used as a backup to send instructions to the UAS (Contarino, Young & Contarino, 2015). At the same time, ADS-B can allow the broadcast of an unmanned aircraft (UA) that has encountered datalink problems to transmit its intent to ATC and other surrounding aircraft using this medium (Valavanis & Vachtsevanos, 2015).

Regarding the need to have comprehensive sense and avoid (SAA) capabilities, current cooperative SAA technologies such as TCAS and ADS-B, when installed on UAS, allows the broadcast of UAS information to other aircraft. However, according to Valavanis & Vachtsevanos (2015), ADS-B does not work on non-cooperative traffic over remote areas such as farmlands, where typical airborne systems use optical sensors, radar or laser scanners. Therefore, it will be a technical challenge ahead for such non-ADS-B equipped airborne systems where SAA is concerned to allow their utilization to be prevalent.

Conclusion
NextGen system will have to accommodate a wider range of aircraft systems such as UAS. It is well anticipated that UAS will be one of the main drivers of NAS demand growth. Therefore, promulgating technically sound UAS integration policies with related human factors considerations in the process is necessary. ADS-B equipage delays are also expected for NAS users with the current high costs of ADS-B equipment, particularly for those owners with low-value aircraft that see little benefits for ADS-B when they do low level flights for farming and other low altitude applications (AOPA, 2015). At the same time, it is still uncertain whether UAS operators are required to have their UA equipped with ADS-B Out. It will still be a long while before UAS can be fully integrated into NAS along with NextGen initiatives.

References
AOPA (2015). Air traffic services brief: Automatic dependent surveillance-broadcast (ADS-B). Retrieved from https://www.aopa.org/advocacy/advocacy-briefs/air-traffic-services-brief-automatic-dependent-surveillance-broadcast-ads-b

Contarino, V.M., Young, S.O., & Contarino, M.R. (2015). Economical safe operation of UAS using ADS-B and RADAR. Retrieved from http://www.auvsishow.org/auvsi2015/Custom/Handout/Speaker9515_Session1011_1.pdf

DOT (2013). Integration of civil unmanned aircraft systems (UAS) in the National Airspace System (NAS) roadmap. Retrieved from https://www.faa.gov/uas/media/uas_roadmap_2013.pdf

Goyer, R. (2015). What is nextgen? Why does it matter?. New York: Bonnier Corporation.

Housten, S. (2016). NextGen in a nutshell. This history and the highlights of the next generation air traffic system. Retrieved from http://aviation.about.com/od/ATC-Technology/p/What-Is-Nextgen.htm

JPDO (2012). NextGen research, development and demonstration roadmap. Retrieved from http://www.dtic.mil/get-tr-doc/pdf?AD=ADA561097

Paczan, N.M., Cooper, J., & Zakrzewski, E. (2012). Integrating unmanned aircraft into NextGen automation systems. Paper presented at the 8C3-1-8C3-9. doi:10.1109/DASC.2012.6382440

Valavanis, K.P., & Vachtsevanos, G.J. (2015). Handbook of unmanned aerial vehicles. New York: Springer

UAS GCS Human Factors Issue

Introduction
The General Atomics MQ-1 Predator is a medium-altitude long endurance (MALE) unmanned aircraft (UA) that is commonly used to carry out a wide range of missions such as surveillance, reconnaissance, close air support and target strikes given its capability to carry multiple sensors and precision weapons when armed (USAF, 2015). A complete set of Predator UAS comes with four unmanned aircraft (UA), one ground control station (GCS), UHF and VHF radio data links for line of sight (LOS) operations, as well as a satellite link for beyond line of sight (BLOS) operations.

Ground Control Station (GCS)
According to Blickensderfer et al. (2012), the purpose of an UAS GCS is to control and monitor the aircraft status, perform navigation and communication, avoid obstacles as well as manage contingencies. Confined in a mobile trailer with an uninterrupted power supply, the Predator GCS comes with air conditioning system, pilot and payload operator stations (PPO), and several other workstations for communications and radar control (Defence Industry Daily, 2011). Due to the long endurance capability of the Predator, a typical mission lasting 12 hours can consist of up to five crew members. A monitor crew to monitor the entire mission; a pilot to fly the UA using a joystick; a sensor operator to operate the cameras, radar and targeting systems; an intelligence officer to analyze the imagery and a flight engineer to monitor the serviceability status of the systems. Each of the workstations will be equipped with two or more screens. All communications are done from the HF/VHF/UHF and the satellite links established by the communications terminals in the trailer.

Associated GCS Human Factors
According to GAO (2008), there are several human factors issues that arise from modern UAS GCS. There is no clear resolution of how many UAS can a single GCS crew operate. For BLOS operations, there is also unresolved issues of communication lag and lost links with UAS. Of the many human factors that are associated with operating MALE UAS such as the Predator, fatigue and loss of situational awareness are two of the most common issues.
 
Fatigue
As a single Predator UAS GCS can be used to control up to four UA, an operator managing multiple UA by monitoring multiple screens over long periods of time with high vigilance is almost an impossible task. The amount of information presented on the screens from multiple UA can be too much for a single operator to handle effectively. It has been reported that UAS pilots are subjected to high levels of stress and fatigue, especially those in the war zone (Tritten, 2015). It has also been reported that UAS pilots suffers from mental fatigue as they often switch back and forth between family and war, thereby creating feelings of being perpetually deployed (Drew & Phillips, 2015). Similar to manned aircraft pilots who fly long haul, UAS operators can also develop back problems due to the extended periods of sitting during UAS long missions.

Lack of situational awareness
According to Valdes (2004), the pilots who flew the Predator described their experience like “flying an airplane while looking through a straw”. Pilots have to rely on the limited sensors on-board the Predator to know what is going on around the aircraft. Unlike a manned aircraft pilot, an UA pilot is not able to get any vestibular or kinesthetic feedback from the UAS operation such as vibrations and sound. This can lead to problems when there is turbulence encountered by the UAS. Even when the pilot has knowledge of the turbulence, as his or her life is not at risk in case of any miscalculation, the pilot may decide to take higher risks and operate the UAS in situations inappropriate for the UA.

Solution
The way to mitigate such human factor problems is to design better ground control stations for the Predator UAS. According to Tvaryanas (2006), one solution is to transfer control of one or more UA to other operators with lower workload. Another is to have screens and windows configurations that can be customizable to suit individual operators’ preferences which will lead to an increased efficiency of operators (Mchale, 2010). General Atomics (2016) have recently launched an advance cockpit GCS that features bigger screens, ergonomic seats and enhanced situational awareness by decluttering through data fusing and integration. Some other solutions include having stereo images to improve depth perception, 3D audio cues and virtual reality googles (Freedberg, 2012).



References
Blickensderfer, B., Buker, T. J., Luxion, S. P., Lyall, B., Neville, K., & Williams, K. W. (2012). The design of the UAS ground control station: Challenges and solutions for ensuring safe flight in civilian skies. Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 56(1), 51-55.

Defense Industry Daily (2011, Oct 3). It’s better to share: Breaking down UAV GCS barriers. Retrieved from http://www.defenseindustrydaily.com/uav-ground-control-solutions-06175/

Drew, C., & Phillips, D. (2015, June 15). As stress drives off drone operators, Air Force must cut flights. The New York Times. Retrieved from http://www.nytimes.com/2015/06/17/us/as-stress-drives-off-drone-operators-air-force-must-cut-flights.html?emc=edit_th_20150617&nl=todaysheadlines&nlid=58656522&_r=2

Freedberg, S.J. (2012, August 7). Too many screens: Why drones are so hard to fly, so easy to crash. Breaking Defense. Retrieved from http://breakingdefense.com/2012/08/too-many-screens-why-drones-are-so-hard-to-fly-and-so-easy/
General Atomics (2016). Advanced cockpit GCS. Retrieved from http://www.ga-asi.com/advanced-cockpit-gcs

Mchale, J. (2010, June 18). Ground control stations for unmanned aerial vehicles (UAVs) are becoming networking-hub cockpits on the ground for U.S. unmanned forces. Military and Aerospace Electronics. Retrieved from http://www.militaryaerospace.com/articles/2010/06/ground-control-stations.html

Tritten, T.J. (2015, June 25). Mccaskill: Drone pilot stress is unprecedented. Stars and Stripes. Retrieved from http://www.stripes.com/mccaskill-drone-pilot-stress-is-unprecedented-1.354681

Tvaryanas, A. P. (2006). Human factors considerations in migration of unmanned aircraft system (UAS) operator control. Retrieved from http://www.wpafb.af.mil/shared/media/document/AFD-090121-046.pdf

USAF (2015, September 23). MQ-1B Predator. Retrieved from     http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104469/mq-1b-predator.aspx
Valdes, R. (2004, April 1). How the Predator UAV works. HowStuffWorks. Retrieved from http://science.howstuffworks.com/predator.htm

The Future of the UAS

The use of unmanned aircraft systems (UAS) may soon become a status quo for many industries in the world. UAS technology comes in a variety of platforms with different shapes, sizes and capabilities. One of the technology that will be receiving substantial attention is how these UAS systems are being powered up. Currently, most of the consumer based UAS are vertical take-off and landing (VTOL) systems in the form of multicopters. However, these VTOL UAS systems lack the endurance of a typical fixed wing UAS because of the enormous thrust required to move them vertically and they are usually powered by lithium polymer batteries, limiting their effective use. Those using combustion engines use non-renewable fossil fuel that is not sustainable in the long run due to the limited supply, and the carbon emission concerns leading to global warming. 

The article I am sharing relates to the UK-Singapore collaboration to come up with a hydrogen fuel cell that is capable of providing power for an unmanned aircraft (UA) for a 300km non-stop flight. Hydrogen fuel cells from Horizon Energy Systems (HES) of UK is recognized as the world’s longest endurance energy storage systems for electrical UAS (Horizon energy systems; UK-singapore collaboration prepares for record 300km hydrogen fuel cell UAV flight, 2015). Fuel cells from HES contributed to the previous world record of a 128km flight by a 5kg Pterosoar UAS system in 2007. The latest fuel cell from HES that is described in the article, with collaboration from a consortium of Singaporean organizations and HES, achieved the 300km flight in 6 hours with a Skyblade 360 UAS built by ST Aerospace. This was considered a significant milestone as it was the first time that a fuel cell went beyond prototype stage into a standard product list of an UAS manufacturer (Press, 2016). 

The introduction of fuel cells into UAS platforms enhances their versatility and allows other mission possibilities for small low altitude UA previously only realisable by larger and more expensive UAS that flies at higher altitudes.  According to Gonzalez-Espasandin, Leo and Navarro-Arevalo (2014), fuel cells have major advantages in terms of endurance, efficiency, emissions, and stealth “, making them ideal for UAS applications in both military and civilian applications. Fuel cell technology will be a feasible implementation as a clean, efficient, reliable, emission free power source that can be asserted in UAS platforms to make longer flights with the growing magnitude of applications today and in the future.

Reference

Horizon energy systems; UK-singapore collaboration prepares for record 300km hydrogen fuel cell UAV flight. (2015). Energy Weekly News, , 114. Retrieved from http://search.proquest.com.ezproxy.libproxy.db.erau.edu/docview/1710690697?accountid=27203

González-Espasandín, Ó., Leo, T. J., & Navarro-Arévalo, E. (2014). Fuel cells: A real option for unmanned aerial vehicles propulsion. The Scientific World Journal, doi:http://dx.doi.org.ezproxy.libproxy.db.erau.edu/10.1155/2014/497642

Press (2016, February 17). New solid hydrogen-on-demand fuel cell from HES Energy Systems flies ST Aerospace UAV for record 6 hours. sUAS News. Retrieved from http://www.suasnews.com/2016/02/new-solid-hydrogen-on-demand-fuel-cell-from-hes-energy-systems-flies-st-aerospace-uav-for-record-6-hours/

UAS use

The rapidly growing popularity of UAS is taking the world by storm. Although UAS are not yet ubiquitous, it is beginning to change the way how movies and TV shows are produced today. The technology of UAS is forging a new frontier in cinematography. The only reason why UAS are not widely used in this industry is not because film makers are not aware of it, but that the aviation authorities have not fully liberalized the use of UAS yet (Burgess, 2015). For many years, the making of movies is done with aerial shots from manned aircraft or from cranes. These methods are both expensive and risky. According to Verrier (2015), an UAS with a camera and crew costs as little as $5,000 a day, compared with at least $25,000 for a manned helicopter shoot. The logistic process involved in a manned flight to take aerial footage can be a laborious. In addition, accident fatalities are not unknown on movie sets, and the use of UAS can take away some of this risks. Verrier reported that in 2013, people were killed when the helicopters crashed during filming of several shows (Verrier, 2015).

Several movie and TV film companies have already gotten approval from FAA to use UAS for filming in the US through section 333 exemptions (FAA, 2014). In fact, movies have already been made using UAS in the past, but mostly outside of US where there are less stringent regulations of such usage. Many scenes in numerous movies such as “The Wolf of Wall Street”, Mission Impossible”, etc. have been produced by UAS (Gamerman, 2015). In Singapore, local film maker Jack Neo has used UAS for several of his movies as well (Lee, 2015).

There are also limitations with using UAS for cinematography. Image quality and stabilization is still not as good as ground setups, and UAS flight endurance using vertical take-off and landing (VTOL) aircraft still remain challenging for any requirement for long aerial shoots. Nevertheless, as UAS assume a growing role in cinematography, movies will continue to be made to provide new perspectives at a low cost.

Reference

Burgess, J. (2015). The five best movie scenes shot using drones. Retrieved from http://www.techradar.com/sg/news/photography-video-capture/the-best-5-movie-scenes-shot-using-drones-1302565

FAA (2014). Six companies can now fly small UAS following FAA approved safety procedures. Retrieved from http://www.faa.gov/news/press_releases/news_story.cfm?cid=TW251&newsId=17194

Gamerman, E. (2015, March 25). Drones invade Hollywood. The Wall Street Journal. Retrieved from http://www.wsj.com/articles/drones-invade-hollywood-1427410534

Lee, M.K. (2015, May 14). Singapore to introduce drone law: 5 things about these flying machines. Straits Times. Retrieved from http://www.straitstimes.com/singapore/singapore-to-introduce-drone-law-5-things-about-these-flying-machines

Verrier, R. (2015). Drones are providing film and TV viewers a new perspective on the action. Los Angeles Times. Retrieved from http://www.latimes.com/entertainment/envelope/cotown/la-et-ct-drones-hollywood-20151008-story.html

Watercutter, A. (2015). Drones are about to change how directors make movies. Retrieved from http://www.wired.com/2015/03/drone-filmmaking/

Unmanned Aerial Systems - Integrating UAS into National Airspace System

The Federal Aviation Administration (FAA) has been very careful about setting the legislation for commercial use of unmanned aerial system (UAS) for a long time, despite the fact that many other countries have already established their regulations to allow UAS operations (GAO, 2015, p.29). The main reason is that of all the safety issues concerning the operation of UAS, the ability to safely maintain proper separation from other traffic in the National Airspace System (NAS) is the most difficult to overcome (DOT, 2013). To FAA, any unmanned aerial vehicle (UAV) has to be able to demonstrate a high level of robustness in terms of its ability to “sense and avoid” other air traffic. As required by Section 332(a) of the FAA Modernization and Reform Act, US. Department of Transportation has released a UAS comprehensive plan to ensure that all commercial airborne UAS are equipment with “Sense and avoid” capabilities (FAA, 2013). “Sense and Avoid” is necessary to achieve autonomy (Yu & Zhang, 2015) and can be achieved via two methods, airborne sensing and ground sensing (Zeitlin, 2010). Airborne sensing will make use of sensors on board the UAV to detect and avoid obstacles, whereas ground sensing makes use of ground radar and other sensors to relay air traffic to the UAV for it to maintain separation from other air traffic. However, airborne sensing requires expensive on-board sensors which can be heavy and consume significant energy. Ground sensing on the other hand, has to be present in the entire operating area of the UAV, making it impractical for long distance flights. 

According to Fasano et al. (2015), the two functions to have separation assurance and to be able to make extreme manoeuvres are key to good “sense and avoid”. Having airborne surveillance for separation assurance and collision avoidance is the ultimate goal of a UAS system and can be achieved using cooperative instruments such as transponders to broadcast and interrogate, and non-cooperative sensors such as Traffic Collision and Avoidance System (TCAS), which has an advantage in case of an air-to-air radio link loss. FAA (2016) states that there are three types of UAS operations: public; civil; and model aircraft. For civil use, special airworthiness certificate can be applied under experimental category; type and airworthiness certificate under Restricted category; and certificate of wavier or authorization under commercial category (FAA, 2016).

Accelerating the use of UAS in commercial applications will provide economic and social benefits. The future of UAS integration into NAS depends upon the pace of FAA development of a comprehensive regulatory framework, which has some urgent need to catch up with the fast developing UAS technologies.

Reference

DOT (2013). Unmanned Aircraft System (UAS) Service Demand 2015-2035: Literature Review & Projections of Future Usage. Retrieved from https://fas.org/irp/program/collect/service.pdf

Fasano, G., Accardo, D., Tirri, A. E., Moccia, A., & De Lellis, E. (2015). Radar/electro-optical data fusion for non-cooperative UAS sense and avoid. Aerospace Science and Technology, doi:10.1016/j.ast.2015.08.010

FAA (2013). UAS comprehensive plan: A report and the Nation’s UAS path forward. Retrieved from http://www.faa.gov/about/office_org/headquarters_offices/agi/reports/media/UAS_Comprehensive_Plan.pdf

FAA (2016). Unmanned aircraft systems: Frequently asked questions. Retrieved March 30, 2016 from https://www.faa.gov/uas/faq/#qn4

GAO (2015). Unmanned aerial systems: FAA continues progress toward integration into the National airspace. Retrieved from https://fas.org/irp/program/collect/gao-15-610.pdf

Yu, X., & Zhang, Y. (2015). Sense and avoid technologies with applications to unmanned aircraft systems: Review and prospects. Progress in Aerospace Sciences, 74, 152-166. doi:10.1016/j.paerosci.2015.01.001

Zeitlin, A. D. (2010). Sense & avoid capability development challenges. IEEE Aerospace and Electronic Systems Magazine, 25(10), 27-32. doi:10.1109/MAES.2010.5631723