Technologies to Help Aircraft Avoid Mid-Air Collisions

October 2009

By Grace Jean

Recent flight tests of newly developed technologies are proving that it is possible to fly manned and unmanned aircraft safely in the same airspace.

“We’re attacking the three or four real key enabling technologies,” says Reece Clothier, project manager of the Smart Skies Project, a three-year research and development project in Australia that is focused on integrating unmanned systems into civilian airspace. It is being funded in part by the Queensland State Government Smart State Funding Program.

His team, in collaboration with Boeing Research and Technology in the United States and Australia and the Australian Research Center for Aerospace Automation (ARCAA) — a joint venture between the Commonwealth Scientific and Industrial Research Organization and the Queensland University of Technology, is helping to develop and test technologies in three areas: global aircraft separation management, aircraft tracking and onboard detection systems for collision avoidance of dynamic and static obstacles.

Boeing’s airspace separation management system concept, called the automated dynamic aerospace controller, or ADAC, employs algorithms to track aircraft and resolve potential conflict situations. It can be located anywhere on the planet to provide four-dimensional separation assurance service to aircraft flying around the world.

The mobile aircraft tracking system, a portable air traffic control radar under development by Boeing Research and Technology Australia, is capable of detecting and tracking aircraft in a five- to 10-nautical mile range. It can transmit traffic information to the ADAC, to local air traffic control and to other airspace monitors.

Finally, the detect, sense and act system is seeking to help unmanned systems perceive and avoid moving and stationary obstacles.

The team completed a full month of flight-testing of the automated dynamic airspace controller (ADAC) in July in Kingaroy, Australia, at a remote test range about four hours northwest of Brisbane. The trials were conducted with up to seven aircraft — three live aircraft including two unmanned systems, and four simulated aircraft including one flown at Sheffield University in the United Kingdom. The aircraft were linked via Iridium satellite and Telstra NextG communications networks to the ADAC separation system, located in Palmdale, Calif.

“We wanted to demonstrate that it could be anywhere,” Clothier says at the Association for Unmanned Vehicle Systems International symposium in Washington, D.C.

In one scenario, a fixed-wing unmanned system and a drone helicopter were put on a collision course. For safety reasons, their actual flight paths were separated by altitude. The ADAC system altered their flight paths to keep them flying safely. In another scenario, the ARCAA airborne systems laboratory — a modified Cessna 172R aircraft — was flown in a range of conflict scenarios with a varying number of simulated aircraft, says Clothier. Pilots in the Cessna flew “hands-off” and monitored onboard displays as the ADAC transmitted separation commands directly into the autopilot system.

The team in December 2010 intends to demonstrate all the technologies in trials that will separate 30 manned and unmanned aircraft, simulated and real, flying within a 10 nautical mile area of the range.

“In the final flight trial campaign, we hope to fly a real conflict scenario between two of the UAS platforms,” Clothier says in an email to National Defense. “We would remove the altitude safety buffer and actually fly the two aircraft at each other relying on the automated airspace separation management system to detect and resolve the conflict.”


http://www.nationaldefensemagazine.org/archive/2009/October/Pages/TechnologiestoHelpAircraftAvoidMid-AirCollisions.aspx