“The sky could become increasingly crowded as personal and commercial uses of unmanned aircraft systems (UAS) become more popular,” said Parimal Kopardekar, manager of NASA’s Safe Autonomous Systems Operations project, as innovators constantly conceive new beneficial civilian applications for these aircraft, including goods delivery, infrastructure inspection, search and rescue, and agricultural monitoring.

Last year, NASA’s Ames Research Center in Moffett Field, CA, released an open call to invite government, industry, and academic partners to collaborate with NASA to conduct and identify research needs, and to accelerate the development of a UAS management system. Around the same time, several major technology companies, such as Amazon and Google, announced plans to launch their own UAS applications. However, before these and any other commercial efforts took flight, a safety system had to be in place to make sure the new unmanned aircraft didn’t collide into buildings, airplanes, or each other.

By leveraging the valuable byproducts of NASA’s aeronautics research, and its decades of experience with air traffic management, NASA is helping to define a new era of aviation. Using the power of collaborative innovation to work alongside many committed government, industry, and academic partners, NASA is benefitting from commercial sector investment in UAS technology, enabling the agency to lead research and development into a cloud-based unmanned aircraft traffic management (UTM) system.

“NASA wants to create a system that would keep track of and deliver important information to operators of UAS, such as which areas they should avoid, whether any other vehicles are trying to operate in the same airspace, and what the weather will be like in a given area,” said Kopardekar.

The NASA team researched and tested ways to communicate this data to UAS while they’re in flight, such as dynamic geo-fences, or virtual barriers, giving UAS operators the most updated information in real time.

NASA will use UTM as a tool to bring more people together and bridge the gap between commercial innovation and NASA’s air traffic management research. By working with partners who provide their own vehicles, low-altitude radar, radio frequencies, or cellphone towers, NASA will gain access to more technology for UTM applications to demonstrate that unmanned aircraft systems can be safely operated at low altitudes.

The UTM is designed to enable safe, low-altitude (~500 ft. and below) UAS operations that predict and manage congestion, avoid terrain and manmade objects, maintain safe separation and spacing, and allow only authorized operation. (NASA)
While NASA and the UAS industry face steep challenges, a number of companies are already addressing some of these issues. One collaborator has developed systems that automatically check a UAS’s battery life and surrounding terrain, while another is building a database to keep UAS away from private residences. Other companies have launched prototypes for low-altitude tracking and avoidance systems, and are using tools that manage fleet operations related to commercial UAS operations. These technologies must meet federal requirements to begin operations as a testbed for a UTM system.

One of the biggest challenges to integrating UAS into the national airspace beyond line-of-sight is developing a system that enables the aircraft to see and be seen by other aircraft. At low altitude, one solution may exist in cellphone tower technology to track and monitor both commercial and civilian aircraft. NASA is in the initial stages of exploring this concept with telecommunication providers such as Verizon. Any system developed would not require tracking, receiving, or interfering with information from any personal mobile devices.

“While these are only examples of the innovative commercial technologies being developed by companies that are working with NASA, the secret to effective collaboration is individuality,” said Kopardekar. “You want everyone to feel free to contribute ideas to a project as a means of increasing engagement.”

Traffic Management

Late last year, NASA successfully demonstrated rural operations of the UTM concept, integrating operator platforms, vehicle performance, and ground infrastructure. The next steps involve further validation through FAA test sites.

“UTM is designed to enable safe, low-altitude civilian UAS operations by providing pilots information needed to maintain separation from other aircraft by reserving areas for specific routes, with consideration of restricted airspace and adverse weather conditions,” explained Kopardekar.

Ames engineers are developing UTM cloud-based software tools in four segments of progressively more capable levels. Level one focuses on a rural environment with applications in agriculture, firefighting, and infrastructure monitoring. With continued development, the system would enable UAS operators to file flight plans reserving airspace for their operations, and provide situational awareness about other operations planned in the area.

A test pilot operates a virtual large UAS, with simulated air traffic, at a NASA research ground control station. The pilot uses the main traffic display for situational awareness. The pilot is connected with a communication headset where he interacts with air traffic control similar to present-day operations. (NASA)
Level two will focus on applications that operate beyond visual line-of-sight of the operator in sparsely populated areas. The system will provide flight procedures and traffic rules for longer-range applications, and is planned for October 2016.

Level three will include cooperative and uncooperative UAS tracking capabilities to ensure collective safety of manned and unmanned operations over moderately populated areas. It’s planned for January 2018.

Level four is planned for 2019, and is designed for higher-density urban areas for autonomous vehicles used for news-gathering and package delivery.

Drone Control Systems

Engineers at NASA’s Langley Research Center in Hampton, VA, have been operating UAS for years to help better integrate drones safely into the skies, develop new uses for UAS, and improve their safety.

“Whenever we operate unmanned aircraft, we use pilots who are trained and certified for those specific kinds of flights and aircraft,” said Tommy Jordan, head of NASA Langley’s Operations Branch. “We review and approve all flights and inspect aircraft beforehand to make sure operations are carried out in a safe manner. In addition to pilots, we usually have visual observers, range safety officers, and communications personnel on hand.”

One of the functions of a cloud-based UTM would be to provide dynamic and static geo-fences that would keep UAS from entering into designated “no-fly” zones. (NASA)
All NASA UAS are registered with an official FAA N-number, just in case one goes astray. That is now an FAA requirement for all drones. Starting December 21, 2015, owners 13 years and older must register small UAS weighing between half a pound and 55 pounds on an FAA Web site (see "FAA and Drone Control").

While the FAA has been working to come up with regulations to allow for wider drone use in the U.S., NASA researchers are working to develop technologies to help improve the drones themselves and the airspace system in which they fly. One place at Langley where engineers are tackling that challenge is the Langley Autonomy and Robotic Center (LARC), formerly known as the Autonomy Incubator.

“What we’re doing at NASA Langley is bringing decades of experience and knowledge in building safe, reliable, robust, highly automated systems, whether those are cockpit-based in an airplane or satellite-based in low-earth or geosynchronous orbit,” said Danette Allen, who heads up the LARC. “We’re trying to bring that same sort of rigor — same corporate knowledge — to these small UAS, and make them as robust and as safe as they can possibly be.”

Among the technologies Allen’s group has looked at are package delivery concepts, obstacle avoidance software, and hand and gesture control systems. Other NASA aeronautics engineers are focusing on improving small drones for other real-world uses such as wildfire spotting, algae monitoring, infrastructure oversight, search and rescue, and weather forecasting.


Another group at Langley, working as part of the Safe Autonomous Systems Operations and UAS in the National Airspace System projects, is developing Safeguard, a safety-net-in-a-box prototype that is small and light enough to be mounted on small UAS at work and play. It’s a new and improved version of geo-fencing technology — software intended to keep unmanned aircraft from entering into designated “no-fly zones” — that is already available on some commercial drones.

“What makes the technology different from existing geo-fencing systems is the built-in safety approach,” said Evan Dill, one of the developers. “NASA engineers, with years of aviation safety research experience, have developed processes and a system design to provide reliability, dependability, and integrity.”

And still other Langley engineers are creating technologies to better integrate larger drones safely into the air transportation system. “There is much research needed to realize the potential of unmanned aircraft, but once it’s done, the sky is literally the limit,” said Guy Kemmerly, Langley’s deputy associate director for unmanned aircraft systems research.

Said Kemmerly, “Our goal is to help speed up technology development and public acceptance of unmanned aircraft so that UAS are so safe that people will demand to be cargo themselves.”

Sensors and Software

Crews inspect a research drone before its test flight at NASA Langley Research Center to make sure it is fit to fly. (David C. Bowman/NASA Langley)
We may be on the cusp of an era in which large UAS will mingle in the nation’s skies with human-flown, passenger- carrying jets. But before a single UAS can join the flying byways, FAA regulations require that it be able to safely and reliably detect and avoid other aircraft. It’s a tricky issue that a team at NASA Langley is working on.

“In particular, the most difficult problem we are trying to solve is how we replace the eyes of the pilot in the cockpit,” said Maria Consiglio, who leads the NASA Langley Sense and Avoid/Separation Assurance Interoperability (SSI) team. “We have developed, and are currently testing, detect-and-avoid algorithms,” she said. “We’re also running multiple research experiments to support the validation of this technology.”

The SSI team’s Detect and Avoid Alerting for Unmanned Systems (DAIDALUS) algorithm could provide the FAA with the framework for keeping unmanned aircraft “well clear” of other aircraft in the National Airspace System (NAS). That’s important because while a large UAS is equipped with several sensors that collect data about its surroundings, there is no pilot in the cockpit to piece that information together.

That’s where DAIDALUS comes in. It works by processing the incoming traffic surveillance sensor data. “What it actually spits out is maneuver guidance for the pilot on the ground to remain ‘well clear’ of other traffic,” said Michael Vincent, a human factors research engineer with the SSI team.

DAIDALUS doesn’t just relay passive alerts, though. It also “sees” safe paths out of potentially dicey situations. “As you progress into an encounter,” said Vincent, “DAIDALUS will provide information on where you should go to avoid other aircraft.”

The SSI team developed and tested DAIDALUS in simulations, including two human-in-the-loop studies that assessed air traffic controllers’ comfort level with the system’s definitions of well clear. For vertical clearance, that definition is about 500 feet. For horizontal, it’s about 1.5 nautical miles.

The SSI team provided data from those simulations to the FAA. According to Keith Arthur, a co-project engineer on the Langley team, that data has significantly contributed to the FAA’s efforts to develop Minimum Operational Performance Standards for UAS.

“NASA has taken a nebulous concept — well clear — and come up with an elegant mathematical solution for it that can be implemented in software,” said Arthur. “So those who are interested now can take that and run with it. They can make avionics software that will keep people safe.”

And the testing continues. In simulations at Langley’s Air Traffic Operations Lab (ATOL), researchers are looking at how well air traffic controllers can manage traffic in simulated airspace that contains both UAS equipped with detect-and-avoid systems and traditional manned aircraft operations. The work at Langley is part of a much broader effort at NASA to integrate UAS into the NAS. Researchers from NASA Armstrong, Glenn, and Ames are also participating in the project.

Ed Waggoner, director of NASA’s Integrated Aviation Systems Program Office, which oversees the UAS Integration in the NAS project, recently visited Langley to witness a live demo of the SSI team’s ATOL simulations. “I was blown away,” he said, “because what they showed me was something that provides the pilot precise decision support information and I truly believe this technology can work in our National Airspace.”

Waggoner believes NASA’s efforts to integrate UAS into the NAS will help open American skies in such a way that large unmanned aircraft will be used for everything from search-and-rescue missions to precision agriculture to airborne photography.

“NASA is so excited to be part of the FAA’s rule-making cadre of information,” said Waggoner. “We’re providing the research for them, the regulators, to make the rules that are going to make the skies safe for the commercial application of UAS. It is what’s happening in aviation right now.”





NASA Tech Briefs Magazine

This article first appeared in the February, 2016 issue of NASA Tech Briefs Magazine.

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