Monday, March 1, 2004
UAVs: Out of Uniform
There is no shortage of civil missions that unmanned air vehicles can perform, as is determined by NASA and the manufacturers of UAVs.
When Greg Holland began working on commercial applications for unmanned air vehicles (UAVs) in 1993, "there was absolutely no one–and now there is quite a growing field of people with various systems, and an even more quickly growing realization that there are real applications for these vehicles," says the president of Aerosonde North America Inc.
In 1993, except for some NASA experiments, there was little interest in UAVs outside of the military. Today, however, companies are exploring a myriad of scientific and reconnaissance activities, including critical post-9-11, homeland security applications, for these relatively low-cost, high-endurance vehicles.
A study by Forecast International projects a UAV market, both military and civil, as high as $7.5 billion in the next 10 years. Such a bullish prediction reflects, in part, the successful military operations in Afghanistan and Iraq. But while the accomplishments of military UAVs, such as Global Hawk and Predator, have been duly reported, word of their commercial applications is just now being heard.
Would you imagine that the vineyards and plantations providing wine and coffee for your dinner table could be protected and harvested with the aid of UAVs? Or that UAVs could help protect against natural disasters, such as wild fires, hurricanes, thunderstorms and even volcanoes?
NASA has tested, or is about to test these applications. The agency is taking the lead in proving that UAVs, equipped with sensor packages, can accomplish such missions better and at a lower cost than the manned aircraft or satellites currently used.
UAV manufacturers—including aerospace giants Boeing, Northop Grumman and Lockheed Martin–along with a number of smaller firms, have teamed with NASA in a long-range program intended to allow UAVs to operate safely, along with manned aircraft, in the National Airspace System (NAS). For an up-to-date picture of these emerging applications and issues, Avionics Magazine talked to scientists, federal agencies and UAV manufacturers throughout the United States.
Northrop Grumman's Global Hawk (shown above), tested in military operations in Afghanistan and Iraq, is considered a major player in the large, high-altitude, long-range UAV market. Roughly the size of a Boeing 737, the RQ-4A model has a 116-foot (35-meter) wingspan. It provides 36-hour endurance without refueling and has been modified to carry a 3,000-pound (1,360-kg) payload to 60,000 feet. The newer-version RQ-4B, with wingspan extended to 130 feet (40 meters), is in its early stages of production and features an open architecture, allowing rapid changes to its sensor package.
"We're making transition to a new payload much easier," says Ed Walby, Northrop's Global Hawk business development manager. "This is important in the dual use of the system–as a DoD [U.S. DefenseDepartment] asset and also for use in support of civil authorities," he says. A veteran of the U.S. Air Force's U-2 spy plane operations, Walby sees civil applications as a natural for Global Hawk. (The U-2 provided peacetime reconnaissance data in support of disaster relief, including the 1993 Mississippi River floods.)
"Now, with Global Hawk, which comes close to matching [the U-2's] capabilities, we can support those civil disasters and make predictive flights." Whereas 26 U2 sorties were flown to film the 1993 flood disaster, the Global Hawk could provide the same coverage in two flights and provide real-time imagery to ground managers.
Northrop Grumman has held recent discussions with the National Oceanic and Atmospheric Administration (NOAA) in a quest to "determine real numbers about global warming," Walby says. The company described a role for the Global Hawk in which the high-altitude, long-endurance platform would drop small temperature- measuring devices from 60,000 feet above cardinal locations around the oceans. The temperature is measured at various times of the day and year–both at the surface and on the ocean floor–and from these changes, an actual global warning rate can be calculated.
"You need something that travels at a fairly high speed, like 350 knots at altitude, and stays airborne for 30 hours, so you can do a series of drops over a large geographical area–6,000 miles of flying, dropping sonabuoys and measuring temperatures," Walby explains. An experiment that demonstrates this technology is tentatively slated for next year.
In addition to three earlier development models that were used in recent conflicts, Northrop Grumman has delivered two low-rate production vehicles to the Air Force. The service plans to purchase 51 Global Hawks, some of which could be used for civil applications, including Homeland Security missions.
Ways to Use Global Hawk
Global Hawk, which is powered by a Rolls Royce Allison turbojet engine, could be used for maritime surveillance, where surface vessels are detected and monitored far off the U.S. coast. Carrying appropriate sensors and transmitting data in real time to command centers, UAVs could be operated out of bases in Alaska, Hawaii, Florida, Mississippi and Virginia, providing round-the-clock surveillance of all open ocean approaches to the United States.
Global Hawks also could aid the U.S. Coast Guard in search and rescue, and in nabbing fish poachers off Alaska's Aleutian Islands. For the latter mission, systems on the UAV would "read the names of hulls from 60,000 feet, check those against records, and allow the Coast Guard to intercept them," says Walby. In disaster relief after, say, an earthquake, Global Hawks could be used for communications relays.
"We put together a package for a [possible electrical] blackout of the East Coast," he adds. "We could have a cell phone relay system on board a Global Hawk and supply emergency communications over the Tri-State complex. Two Global Hawks could do it indefinitely." In Hawaii, when a hurricane knocked out power on the "Big Island," the UAVs could have provided immediate communications, says Walby.
Border patrol is another application being studied. UAVs could provide a broad area sweep, and then narrow the field of view to focus on activities that authorities need to intercept along U.S. borders. This tactic could also be used for the similar counter-drug mission.
All types of sensor packages work on the Global Hawk, Walby asserts. In Iraq radar was used to search and identify potential targets, which were verified or further identified with an electro-optical system or an infrared system, if at night.
Global Hawk can operate autonomously or be controlled from the ground. "You can completely pre-program it, launch it with the click of a mouse, and the computer flies it," says Walby. "It can look at pre-loaded targets and then come back without [personal] interaction." GPS is used for navigation.
In controlled flight, the "pilot" gives the UAV its heading and altitude through inputs on the keyboard or mouse. However, the pilot does not physically maneuver the aircraft through the control surfaces. That chore is left to a computer, so the pilot can concentrate on the mission, Walby explains.
On military missions a sensor operator would join the pilot in a control center that could be located a continent away from the operation. "For homeland security it doesn't matter where the cockpit is. Because of the satellite link to the vehicle, you can have ‘mission control' at the launch base or in an office, if you want." Global Hawk uses both direct, line-of-site links and commercial satcom, including Inmarsat, for over-the-horizon communications. �������
Boeing offers ScanEagle in the commercial arena. A derivative of Insitu Group's SeaScan miniature robotic aircraft–originally developed for commercial fishing fleets to spot tuna–ScanEagle is a low-cost, long-endurance vehicle that uses Boeing's systems integration, communications and payload technologies. Boeing and Insitu are partners; the UAV is produced at Insitu's facilities in southeastern Washington.
ScanEagle takes off autonomously from a catapult launcher and flies pre-programmed missions, using GPS navigation. It is retrieved using a "sky hook" system, in which a rope, hanging from a 50-foot- (15-meter)-high pole, snags the UAV. It can operate from small sea vessels, forward fields or mobile vehicles. ScanEagle measures 4 feet (1.2 meters) in length, has a 10-foot (3-meter) wingspan, weighs 33 pounds (15 kg), reaches a maximum speed of 70 knots (it cruises at 50 knots with a service ceiling of 16,000 feet), and boasts an endurance range of 25 to more than 40 hours. To date, its longest flight has been 15.2 hours.
"Most small UAVs of this class fly for about two to six hours," says Al Awani, ScanEagle program manager in Boeing's Integrated Defense Sysems. He explains that the current two-stroke reciprocating engine, with fuel injection, will be replaced by a four-stroke engine for longer range.
Another touted advantage is ScanEagle's low cost. The air vehicle itself carries a price tag of $72,000, but the cost of the complete system, including launcher, sky hook vehicle, and ground support package, rises to $420,000. Since its first flight in April 2002, three prototypes have completed more than 70 sorties, and the first production model flew last August.
When launched, the UAV operates autonomously, and its inertially stabilized turret can lock onto a target, using a video camera's or sensor's full functionality. And when it returns, it can recover itself. "Using differential GPS, it flies into the sky-hook system," Awani says. "If it's not functioning the way we want, we can overide and take over," he adds. "We can give it a new mission, change the route or select an alternative site to land."
Boeing and Insitu foresee roles for ScanEagle in the homeland security and commercial, as well as military areas. These include search and rescue, border patrol and pipeline monitoring–with sensors able to detect small natural gas leaks. Surveying high-voltage electrical power lines and monitoring nuclear power plants for sabotage are other potential uses.
"An advantage is its very small footprint," says Awani. "It can take off and be recovered from a small sea vessel anywhere in the world. That means I can extend my range substantially." A removable avionics bay allows for the integration of unique mission sensors.
In January 2003 ScanEagle took part in the U.S. Navy's Giant Shadow exercise in the Bahamas. During five flights, it showed its ability to serve as a multi-path data link between ships, aircraft and submarines, while also providing real-time video to exercise participants. This capability could also be useful in homeland security, including maritime surveillance, says Awani.
At the same time Insitu's SeaScan program is moving into the test and integration phase for use in the commercial fishing market. The product derived from Insitu's Aerosonde, which in 1998 was the first UAV to cross the Atlantic, in 27 hours on 1.5 gallons (5.7 liters) of fuel. (Insitu licenses technology to Aerosonde in Australia.)
Commercial fishing operators have traditionally relied on helicopters for fish reconnaissance. Large operations "like tuna fishing fleets use aerial reconnaissance with manned vehicles," says Steve Nordlund, business development vice president for Insitu in Bingen, Wash. "But with helicopters, there is only two hours of endurance and a high accident rate, so a lot of these fleets have discontinued this activity," Use of a long-endurance UAV for this mission seemed a natural.
AeroVironment Inc., the largest supplier of small UAVs to the military, has formed a subsidiary, SkyTower, to pursue UAVs for wireless communications. Its high-altitude platform station (HAPS) could serve as a 12-mile-high (60,000-foot) tower, 1,000 times closer to the Earth than a geostationary satellite, says Stuart Hindle, vice president of strategy and business development.
HAPS is based on AeroVironment's Helios, an unmanned solar/hydrogen-powered airplane. With a 247-foot (75.2-meter) wingspan, Helios is, essentially, a flying wing. The first commercial telecom operations with the UAV were demonstrated in 2002 from 12.4 miles (20 km), providing high-definition TV and IMT-2000 (third-generation mobile phone) service.
HAPS is designed to operate continuously for up to months at over 60,000 feet in the stratosphere, above weather and commercial air traffic. It could provide low-cost broadband, narrowband/voice, and direct broadcast video/audio services. Broadcast capacity per platform is projected to be 5 gigabits/s for the first-generation system. Service providers, including Internet service providers (ISPs), will be able to purchase the system either to enhance existing infrastructure or to develop new infrastructure.
The new service, currently in development and testing, "will provide broadband services at a fraction of the cost of a satellite or even cable DSL [digital subscriber line]," Hindle claims. "Using a fixed dish antenna, like a satellite TV antenna, a person can communicate with our aircraft, connecting him to a fiber optic backbone. It would replace hundreds of cell sites or hub sites."
The first production systems will use liquid-hydrogen-powered fuel cell systems and give the advanced version of Helios seven to 10 days' endurance, he adds.�
Aurora Flight Sciences
Aurora Flight Sciences Corp., which worked with NASA on the Environmental Research Aircraft and Sensor Technology (ERAST) program, has produced several aircraft, including the Perseus and Theseus. Aurora sees UAVs replacing manned air vehicles in law enforcement, homeland security and emergency operations.
"We estimate that almost 250,000 manned flight hours for U.S. law enforcement surveillance annually, at an estimated cost of more than $150 million, could be accomplished with UAVs," says Greg Slabodkin, Aurora's communications manager. Aurora foresees applications in agriculture, oil and gas, and maritime.
For the very small UAV market, Aurora is developing its Golden Eye-50, a vertical takeoff and landing (VTOL) aircraft that weighs 16 pounds (7.3 kg), cruises at 100 knots, and flies at 5,000 feet. It is being designed for ship-based missions, as well as operations in remote areas in both civil and military markets. It requires no launch equipment. Aurora foresees Golden Eye carrying surveillance and hazardous agent detection sensors to restricted, difficult-to-reach or dangerous locations.
Aerosonde, produced at Aerosonde Ltd.'s facility in Melbourne, Australia, is offered in the United States by partner company, Aerosonde North America. Some 70 of the small, relatively low-cost UAVs have been produced, and the U.S. affiliate, which modifies and integrates sensor packages, has 20 in its fleet. The UAV has a 10-foot (3-meter) wingspan and weighs under 30 pounds (13.6 kg). It has an endurance of more than 30 hours at a speed of 50 to 100 mph and flies up to 21,000 feet.�
The firm is teaming with NASA to provide scientific services. Its UAV will cover a range of activities, from monitoring ocean conditions to tropical cyclones and other types of weather to volcanic eruptions.
Another NASA mission is to study waves, a requirement for real-time weather and ocean forecasting.
NASA Backs Civil UAVs
NASA is conducting unmanned air vehicle (UAV) flights to demonstrate commercial and research applications under the auspices of its new UAV Applications Center. "We plan to transfer technology to the marketplace," says Stan Herwitz, center director. A goal is to change public attitudes about UAVs, stressing their useful role in the civil sector.
A demonstration planned for April will use a small UAV built by R&R Technologies. The craft will fly as low as 3,000 feet to detect temperature variations in a 3,000-acre wine vineyard–the largest in California–to monitor potential freezing. The UAV will fly an overnight mission, sending thermal sensor data down to a ground server station.
"As a result, the vineyard owner can mitigate potential frost problems by applying water to prevent freezing," says Vince Ambrosia, senior research scientist at NASA-Ames.
The Herwitz team also conducted a demonstration in Hawaii in 2002. On that mission, the UAV supplied images of a large coffee plantation on the island of Kaui, sensing which areas were ripe and needed harvesting and relaying that information to the harvest manager.
Working with the U.S. Forest Service, NASA Ames will continue research into wildfires and forest fires. "They are interested in looking at the utility of UAVs and sensor technology–uplinking and downlinking data sets from UAV platforms–for potential use in the future, either by their purchasing UAVs or contracting them," Ambrosia says. Last fall, during the Southern California wildfires, NASA took a manned platform it uses as a surrogate UAV and tested the same sensor package over the fires.
For the fire mission, NASA uses a thermal sensor, "a scanning mirror assembly that has four channels–two channels in the thermal infrared [IR], one channel in the middle IR [reflected, near-IR], and one channel in the red portion of the spectrum the human eye can see. By looking at various combinations of channels, we can discriminate temperatures down to less than half a degree–all the way up to 700 degree C," Ambrosia explains.
Ambrosia and colleagues at Ames developed the sensor package, called AIRDAS (airborne infrared disaster assessment system). One demonstration mission, using AIRDAS on an Altus UAV, was flown in September 2001. For the next phase, this summer, they hope to demonstrate AIRDAS over a "real fire" in the Sierra Nevada mountains.
"The image data is sent down from the aircraft fully geo-rectified, so it can be integrated into a map base right away," says Ambrosia. "No work will be required on the ground."
Another demonstration, called the Western States Mission, is planned for 2005. It will use Altair and the AIRDAS, and fly a 24-hour mission over the continental western United States to observe fires "from Mexico to Canada and from the Pacific Ocean to Denver, a 4,200 mile range." A 24-hour mission is something that hasn't been done outside the military.
The UAVs in these missions will be controlled from the ground with the control center probably located in southern California, near the Dryden Center, the UAVs' home base.
A factor inhibiting even faster growth of commercial UAVs is their ability to operate in the National Airspace System (NAS). Current rules require a lengthy lead time in filing flight plans and in obtaining Federal Aviation Administration (FAA) approval, which limits the UAVs' ability to respond to national disasters. An exception is the Air Force's Global Hawk, which is allowed to operate above 40,000 feet if a flight plan is filed five days in advance.
To address this problem, NASA has launched Access 5, a project to develop the procedures and technologies that will enable UAVs to fly with the same level of safety as a manned aircraft in a mix of manned and unmanned aircraft. The goal is to open the NAS safely and seamlessly for routine high-altitude, long-endurance (HALE) UAV operations.
�A government and industry consortium is involved in the project, based at NASA's Dryden Research Center. The Defense Department is a player, and FAA participates in an advisory role, joined by major UAV producers. "It's not going to happen overnight," says NASA spokesman Alan Brown. Access 5 will concentrate initially on HALE missions operating above 40,000 feet. Subsequent steps will deal with UAVs operating above 18,000 feet.
UAVs would have to have onboard systems to detect, see and avoid (DSA) other aircraft. In March 2002, NASA Dryden in cooperation with New Mexico State University and FAA, conducted the first flight demonstrations of an active DSA system.
In April 2003, a second series of flight demonstrations, focusing on "non-cooperative" aircraft–without operating transponders–was conducted in restricted airspace near Mojave, Calif. A Scaled Composites Proteus UAV was equipped with an Amphitech OASys 35-GHz primary radar system to detect a mix of seven intruder aircraft ranging from a sailplane to a jet. Radar data was telemetered directly to the ground station, as well as via an Inmarsat satellite. The radar picked up the intruding aircraft at ranges of 2.5 to 6.5 miles. A remote pilot on the ground was able to direct Proteus to take evasive action if needed.
"They did work but didn't really give us enough advanced warning," says NASA's Brown. Engineers believe some upgrades would have to be made to the detection systems. "Successful demonstration of collision avoidance systems is critical to confirming the ability of UAVs to fly safely and routinely within the [NAS]," NASA concluded.