Collision avoidance technology for unmanned aircraft years away.

• Author: Tadjdeh, Yasmin

Experts have said that the integration of small unmanned aerial systems into the national airspace will open up a slew of new applications and pump millions of dollars into the economy.

However, a key enabler of unlocking that promise has so far remained elusive for federal regulators and industry.

Sense-and-avoid technology is a conundrum for unmanned aerial vehicle engineers and researchers. Ideally, such a system--which could be airborne, ground-based or a combination of the two--could autonomously alert a drone that it is about to collide into another aircraft, manned or unmanned, a building or even a bird.

Much research has been devoted to finding a viable solution, but experts say at best the technology is still years away from implementation.

"We're going to be looking at this issue for a long time," said retired Air Force Maj. Gen. James O. Poss, who leads the Alliance for System Safety of UAS through the Research Excellence (ASSURE) coalition.

ASSURE comprises 21 research universities and more than 100 industry and government partners.

UAS integration into the national airspace will have to be done in baby steps, Poss said. It is the "first wave" of autonomy to really affect the public, he noted.

One major milestone occurred earlier this year when the Federal Aviation Administration--the agency tasked with regulating drones in the national airspace--released a proposed rule for small UAS. The document, which was up for public comment through April, stipulated that operators must fly during the daytime and within a user's line of sight.

While the FAA is moving cautiously, those rules--particularly requiring line-of-sight operations--could severely hamper the commercial UAS industry, Poss said. "Most industry partners require beyond visual line-of-sight authority to make money," he said.

For instance, while precision agriculture has been touted as one application for drones, only select farmers will be able to take advantage of the technology as the rule stands now, he noted.

"If you're doing walnut farming or ... [growing grapes for] wine in California you can maybe get away with an unmanned vehicle that can only fly five to seven miles from its operators because they're relatively compact crops," he said. But for many farmers whose land spans hundreds of acres, a drone will have to go beyond line of sight to be effective.

However, even if the rule were revised, "it's very difficult to go beyond visual line of sight without some...