Stanford lab developing small UAS traffic management solution

By Patrick C. Miller | January 07, 2016

Mykel Kochenderfer, director of the Stanford Intelligent Systems Laboratory (SISL), describes solving the problem of traffic management for small unmanned aerial systems (sUAS) below 400 feet as “tricky business.”

Software for automated conflict avoidance being developed by a team at SISL might provide the answer to how Amazon, Google, Walmart, Best Buy and thousands of other commercial operators will be able to safely integrate sUAS into the national airspace.

“Critical to the system is conflict avoidance; you just have to have this,” Kochenderfer said. “What we have implemented so far has been found to be a very promising approach. I believe this is a major stepping stone for enabling more flexible airspace access.”

As an assistant professor of aeronautics and astronautics at Stanford University in California, Kochenderfer and Hao Yi Ong—a mechanical engineering graduate student—are working with NASA’s UAS Traffic Management (UTM) program at the nearby Ames Research Center for a solution that will enable multiple sUAS to operate simultaneously in a confined airspace such as an urban area.

According to Kochenderfer, there are three primary challenges in making such a system work. The first is imperfect information about the relative positions and velocities of all the sUAS operating in a given area. The second is not knowing where the drones will be in the future.

“The third challenge is that you need to be really safe without alerting too often or producing too many unnecessary maneuvers,” Kochenderfer explained. “If you produce too many unnecessary maneuvers, the operator will stop paying attention to the system. Or if they do follow it, it’s a major disruption to the mission they’re trying to accomplish—like package delivery or agricultural monitoring.”

The solution he and Ong arrived at is partially based on technology Kochenderfer developed while working at the Massachusetts Institute of Technology (MIT) known as Airborne Collision Avoidance System X (ACAS X). Designed for large UAS operating above 400 feet in the same airspace as manned aircraft, a version known as ACAS Xu is being tested by the U.S. Federal Aviation Administration (FAA), NASA, General Atomics and Honeywell at the NASA Armstrong Fight Center in California.

The difference is that while ACAS X is a collision avoidance system, the UTM solution SISL is developing for sUAS is a conflict avoidance system. It’s designed to automatically prevent conflicts long before they become potential collisions, Kochenderfer said.

Rather than having a human operator attempt to determine how to avoid a possible conflict, a computer uses specially developed algorithms to quickly and safely de-conflict sUAS.

“The computer can do it faster and take into account many more different scenarios than a human,” he said.

Starting last year, NASA began rolling out the first of four builds of UTM, a process expected to continue through 2019. Kochenderfer called the timeline aggressive, realistic and technically achievable.

“Much of the timeline involves the validation of these algorithms and technology validations through flight tests and demonstrations,” he said. “There isn’t really a good way to speed that up.”

However, he noted that it’s not necessary to have the entire UTM system completed and in place before UAS integration into the national airspace can begin.

“We didn’t wait until we had the Boeing 747 to start flying people around,” Kochenderfer explained. “We made gradual steps in pretty much all aspects of aviation technology. And because of these systems are safety critical in nature, it’s really important to incrementally validate the system.”

He believes that development of the UTM system shouldn’t be rushed.

“From my perspective, we really need to take baby steps to where we want to go and build up our confidence in the system along the way,” Kochenderfer said.

 

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