Flying blind seems safeUnmanned aircraft could soon go it alone.
19 March 2002
TOM CLARKE
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NASA, US Navy and academic scientists met test pilots at a desert airfield in New Mexico last week to fly planes at one another. Their tests should help fledgling robotic vehicles fly the nest within a few years to safely share crowded skies with other aircraft.
Uninhabited aerial vehicles (UAVs) such as the US military's Predator , have served as reconnaissance and attack aircraft in war zones, including Kosovo and Afghanistan. Flying autonomously or piloted remotely from the ground, they could, in theory, survey weather patterns, monitor forest fires or road traffic, or even relay telephone calls over long distances.
But to be allowed into civilian airspace, UAVs must be trusted not to fly into other aircraft. "We need to replace pilots with other sensory systems," explains Steve Hottman of New Mexico State University, who convened last week's trial - the first test of such 'see-and-avoid' systems on an UAV.
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The UAV, called Proteus, was kitted out with Skywatch, a radio-based device that scans skies 20 miles around for other aircraft. Test aircraft, including a high-speed F-18 jet, also equipped with Skywatch, were flown at Proteus.
Skywatch is cooperative. It communicates with other similarly equipped aircraft, exchanging information on course and speed and figuring out how to avoid collisions. In the test, all the Skywatch software was tweaked to make the vehicles 'think' that they were on collision courses. But for safety, the piloted aircraft in fact passed about 300 m from Proteus.
It seemed to work, says Hottman: "We're very excited with the results so far." He hopes that the US Federal Aviation Administration (FAA) will allow UAVs to take to the skies within five years.
"We can recommend certification and regulatory procedures to the FAA based on actual flight verification," agrees Jeff Bauer, director of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) programme.
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Next week, Bauer's team plans to demonstrate the remote sensing capabilities of a NASA UAV called Helios. They have equipped the high-altitude, solar-powered craft with an infrared camera. They hope to predict the ripeness of coffee berries in Hawaiian plantations and to advise growers on the best time to harvest.
To meet the required safety levels, non-cooperative see-and-avoid systems are also being tested. One is a camera-based device that calculates the course and trajectory of other aircraft to avoid them without input from them or the ground.
© Nature News Service / Macmillan Magazines Ltd 2002