The City Beat has finally gotten a handle on UND stories that don’t involve the Fighting Sioux nickname or any administrative stuff, which is what I’ve been trying to do for the past several months. As I’ve said before, I really think the heart of university coverage — or at least one part of it — is the intellectual endeavors that its faculty and staff embark on. That’s what makes a university town different from other towns: There’s a lot of really smart people studying a lot of really interesting things.
This weekend, I got a story in about the new ScanEagle unmanned aircraft at UND, which would be used to test a new concept for opening up civilian airspace to unmanned aircraft. While the aircraft itself looks pretty awesome, and, for something that you can haul around on your shoulders, it has some neat abilities, I resisted the gadget-geek impulse and focused on the airspace concept.
(Plus that ScanEagle is pretty tiny, even if it does look like a baby missile.)
Ben Trapnell, the guy responsible for developing the unmanned aircraft degree program at UND, came up with the idea of using three inward-looking radars to form a triangular column of airspace where something as small as a goose would not escape unnoticed. He wrote a paper about it a while back and now, with the ScanEagle, he’ll be able to test the concept.
As you’ve read here before, the problem with mixing unmanned aircraft with manned aircraft is the fear that some unmanned aircraft operator on the ground won’t see a manned aircraft nearby and would accidentally hit it and cause people to die. There are two ways to reduce the risks of that happening.
One is to have technology that allows an unmanned aircraft to automatically avoid other aircraft. Unfortunately, that technology is still in the lab, including one at UND.
The other is to fly the unmanned aircraft within visual range of the operator, just like an RC plane. Obviously, that’s a pretty limited block of airspace. Ben’s innovation is to extend the visual range with radar.
Now, radar’s been extending visual range since World War II, so this is nothing new. But radars, even modern ones, have their limitations.
What radars do is bounce radio waves at objects and wait for the reflection. The longer it takes for the reflection to come back, the farther away the object is. The problem with radio waves is that they don’t bounce real well off things that aren’t metal, such flesh or nylon — that is, a man on a parachute — or wood and canvas — a biplane, say. And, like lightwaves, more of the radio waves bounce back when there’s more surface area to reflect off of. So a plane seen from the side by radar will be easier to see than head-on.
To satisfy the FAA’s safety requirement, Ben thinks that those limitations have to be minimized so that no matter what the object is made of or how it turns, it’s going to show up. His idea was to point the radars inward, take their signals and fuse it into one radar screen. So you’ve got three times as many radio waves in a given volume and they’re coming from different directions so wherever an object turns, it’ll still be at an optimal angle to at least one radar.
Another advantage of a trio of radars is redundancy. All three would have to fail before the unmanned aircraft operator goes blind.
On thing I didn’t mention in my story is that these radars would be phased-array radars. These are radars made up of hundreds or thousands of tiny transmitters and receivers whose beams of radio waves are electronically steered. That is, instead of having a radar dish that turns around and around, slowly, you’ve got beams of radars scanning the sky hundreds of times a second. To the radar operator, it means that he can see the entire sky at once without having one part disappear because the dish had turned away.
If I remember right, phased arrays can also focus their beams on certain areas, which would help to see nonmetalic objects better.
The ScanEagle is the guinea pig in all this. It’s the first unmanned aircraft UND’s got that can fly over many, many miles. The university has less than five now and all the others are just big RC planes so they don’t have quite the range.
UND will fly ScanEagle around in the triangular column along with other kinds of aircraft to see if the radars work as Ben expects. The university will also test the system in different weather conditions, because rain and clouds can mess with radar. Ben said he hopes he’ll be able to spot flocks of geese with the radar system. I wonder how he’ll get the geese to cooperate!