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Tuesday, December 1, 2009

Preferred Payloads

Unmanned aircraft are platforms for increasingly capable payloads containing radar, cameras and infrared sensors, laser rangefinders

Frank Colucci

While armed Predators and Reapers make headlines hunting terrorists and insurgents, other unmanned aircraft systems (UAS) quietly fight what was formerly known as the Global War On Terror with Intelligence, Surveillance and Reconnaissance (ISR) payloads.

By September this year, the U.S. Army alone had flown more than 760,000 hours in Operations Enduring Freedom and Iraqi Freedom, with five different types of unmanned aerial vehicles (UAVs). The U.S. Air Force, Navy and Marine Corps operated UAVs ranging from the 1-pound Wasp to the 32,000-pound Global Hawk.

Canada, Australia, France, the United Kingdom and other partners in the International Security Assistance Force (ISAF) in Afghanistan have launched Skylarks by hand, improved Sperwers from catapults, and long-endurance Herons and French SIDM/Eagles from runways.

Unmanned systems include the air vehicles, datalinks to ground control stations and mission payloads. Operators of close, short, tactical and long-endurance systems generally want sharper sensor resolution, greater sensor range and more data throughput from the different classes.

"We’re seeing a significant growth across all of them," said Todd Gautier, vice president of business development for payload supplier and integrator L-3 Communications Sensors & Simulation Group, based in New York City. L-3 stresses open architectures with non-proprietary hardware and software interfaces for rapid, low-cost payload integration across platforms, he explained. "We think of the air vehicle as merely another component in the systems architecture," Gautier said.

The U.S. Army in September broke ground on a UAS Rapid Integration and Acceptance Center (RIAC) at Dugway Proving Grounds, near Salt Lake City, to reduce payload integration times by 50 percent and costs by 30 percent, according to the deputy program manager for UAS. The Army UAS Project Office currently works with the Marines and Joint Special Operations Command, and also expected the Navy to participate in the new RIAC.

The U.S. armed services already share operational payloads on like platforms. The Marines acquired the AAI Shadow Tactical UAS as an interim replacement for long-serving Pioneers, with the same Israel Aerospace Industries Tamam Plug-In Optronic Payload (POP) flying on the Army Shadow. According to Marine Lt. Col. James Roudebush, with the Navy’s Small Tactical UAS program office, "Our goal was to procure the exact same system the Army is buying off the line. That way we can have the same logistic footprint and take advantage of their training."

Despite a new phased array radar and other sensors optimized for overwater missions, the Navy Broad Area Maritime Surveillance (BAMS) system will retain the Raytheon AN/AAS-52 MTS-B Multi-Spectral Targeting System equipped on the Air Force’s MQ-9 Reaper. "We’re likely to keep that as a standard configuration," said Navy Capt. Robert Dishman, BAMS program manager. "I know they are continuing to upgrade variants of the MTS-B. We’ll take whatever that configuration is to reduce cost and keep sustainment commonality."

User Needs

UAS payloads are nevertheless tailored to user missions. For Joint Explosive Ordnance Disposal units, the Navy modified the payload of the Honeywell T-Hawk Micro Air Vehicle (MAV) originally aimed at the Army’s Future Combat Systems Class I requirement. The 17-pound, ducted-fan MAV initially carried two fixed, interchangeable electro-optical or infrared cameras manufactured by FLIR Systems, of Portland, Ore. The productionized RQ-16B now has a modified camera zoom function and a gimbal to vary the depression angle of the sensors in flight.

The Navy program office also was considering an airborne chemical detector for the T-Hawk, but Roudebush noted, "We’ve got about three pounds of margin to put a payload on, so that limits our capability to do that."

Other man-portable UAVs are widely used in Iraq and Afghanistan. The AeroVironment RQ-11B Raven, in combat with the U.S. Army since 2004, now watches over Marines with three quick-change sensor noses for daylight and infrared cameras. A forward-looking IR payload was specifically requested by the Marines, and other payloads can include a laser illuminator to cue night vision devices.

AeroVironment, based in Monrovia, Calif., buys sensors and integrates them into the vehicle architecture. For example, FLIR Systems provides the Photon 8- to 12-µm long-wave infrared cameras in the Raven. Video imagery and identifying metadata from the vehicle streams line-of-sight to the ground control station via a four-channel analog radio frequency link. AeroVironment now offers a new digital datalink with 40 channels and greater signal security.

Canadian, Australian and other allied forces in Afghanistan have adopted the Elbit Skylark mini-UAV, with Elbit’s own MicroCoMPASS payload containing a 3- to 5-µm mid-wave thermal imager and CCD television camera. The latest MicroCoMPASS 4 configuration, including laser rangefinder and laser pointer, weighs about 20 pounds.

"People want lasers on everything. They want as much capability as possible, but within the capabilities of the UAV," said Dave Strong, vice president of marketing for FLIR Systems Government Systems Division. FLIR developed the 1.5-pound Cobalt 90 gimbal with TV, IR and laser designator specifically for the lightest platforms.

Larger tactical vehicles naturally provide more payload capability than micro- and mini-UAVs. The MQ-5B Hunter still in the U.S. Army inventory has traded its IAI Tamam Multi-mission Optronic Stabilized Payload (MOSP) for an EO/IR package with better resolution and a laser designator to guide Viper Strike munitions.

Since initial fielding, the RQ-7B Shadow has upgraded to an IAI Tamam EO/IR gimbal with better cameras and a laser pointer. The POP300 payload weighs about 35 pounds. A laser designator/laser rangefinder is in development for the Shadow, and a communications relay payload is in use — the U.S. Army wants Signals Intelligence (SIGINT) and communications relay functionality on every UAS larger than the Raven.

The Sagem Sperwer, which was phased out by the Canadian military after three years in Afghanistan, is still flown by the French Army in an improved version with the company’s EuroFLIR payload. The EuroFLIR packages an 8- to 12-µm or 3- to 5-µm thermal imager with a high-definition color TV camera, laser pointer and laser rangefinder. Depending on the environment, long-wave IR gives best clear-weather range while mid-wave sensors better penetrate fog and obscurants.

With UAV runways plentiful in both Iraq and Afghanistan, the U.S. military will not rush an unmanned helicopter into the combat theaters, as vertical takeoff and landing comes with shorter endurance and higher operating costs. However, the Navy MQ-8B Fire Scout has embarked on its first Caribbean counter-drug deployment aboard the frigate USS McInerney with the state-of-the-art Brite Star II EO/IR laser designating payload from FLIR Systems. The Army’s Future Combat Systems plan designates the Fire Scout as the XM-157 Class IV brigade-level UAS equipped with the same Northrop Grumman AN/ZPY-1 STARLite Synthetic Aperture Radar/Ground Moving Target Indicator (GMTI) radar planned for the MQ-1C Sky Warrior Extended Range Multi-Purpose (ERMP) UAS.

The U.S. Army’s Hellfire-armed Sky Warrior builds upon the success and shares some of the payloads of the General Atomics Predator and Reaper Medium Altitude Long Endurance (MALE) air vehicles in service with the Air Force, Army and other government agencies.

Air Force Reapers went to Operation Enduring Freedom with the MTS-B EO/IR payload and General Atomics Lynx Block 20 radars in 2008. The Army subsequently rushed Quick Reaction Capability Sky Warriors to war with the Raytheon AN/DAS-2 EO/IR/laser gimbal and Lynx Block 30 radar. Production Sky Warriors in the First Unit Equipped will carry the Raytheon AN/AAS-53 Common Sensor Payload (Avionics, August 2008, page 24). Plans call for the Second Unit Equipped to receive the 65-pound STARLite radar. Sky Warrior Threshold requirements add both SIGINT and Warfighter Information Network relay payloads.

The Northrop Grumman RQ-4 Global Hawk remains the largest High Altitude, Long Endurance (HALE) UAS in operation. The current Block 20 Global Hawk has a Raytheon Enhanced Integrated Sensor System, including synthetic aperture radar with 0.3 m spot resolution and high-resolution electro-optical/near-IR payload for still mosaic imagery. The Navy BAMS-D demonstrator adds an Automatic Identification System developed by the Naval Research Laboratory to identify cooperative ship transponders. The Increment One BAMS will integrate the Raytheon MTS-B EO/IR streaming video sensor with the Northrop Grumman Multi-Function Active Sensor (MFAS) active electronically scanned array (AESA) radar, due to fly in late 2011 or early 2012. Northrop Grumman recently flew the Multi-Platform-Radar Technology Insertion Program (MP-RTIP) AESA sensor for the Air Force Global Hawk Block 40.

To traffic high-definition video and other data, BAMS trades the 10.7 Mbit/sec Global Hawk datalink for a non-proprietary datalink with twice the capacity. The Navy RQ-4N will also integrate a VHF/UHF relay payload to connect low-flying maritime patrol aircraft and helicopters with surface vessels. Electronic Intelligence (ELINT) payloads will evolve from Specific Emitter Identification in the Increment One BAMS to Communications Intelligence (COMINT) in Increment Three.

What Next?

While UAS users leverage off-the-shelf payloads, all the U.S. services are pursuing advanced technologies singly or teamed with other agencies. The U.S. Army Communications-Electronics Research Development and Engineering Center (CERDEC) Intelligence & Information Warfare Directorate (I2WD) at Fort Monmouth, N.J., is working on pre-production radar and electronic intelligence technologies for UASs. It collaborates with the Defense Advanced Research Projects Agency (DARPA) on the ground moving target indicator (GMTI) radar tested on the Boeing/DARPA Hummingbird unmanned helicopter. The CERDEC Night Vision and Electronic Sensors Directorate (NVESD) at Fort Belvoir, Va., meanwhile, focuses on EO/IR technology.

"Most of our work most recently had dealt with UAV payloads. We do not take things into production. We develop prototypes based on a capability gap demonstrated by the user community," said CERDEC NVESD Air Systems Division Director Fred Petito.

User requests for better resolution and greater range make bigger payloads that cut into UAV endurance. "You’ve got to start shrinking things," said Petito. NVESD engineers have reduced laser designator weight from 12 pounds to just 1.25 pounds and expect to fly a 7-pound gimbal for a backpack-portable Class 1 UAV in two to three years. A super-resolution Common Sensor Payload with two-color mid-wave/long wave IR camera and Aided Target Recognition could transition to production in four years.

The Army CERDEC I2WD, with laboratories at Fort Monmouth and test aircraft at nearby Lakehurst Naval Air Station, is a one-stop shop for radar and datalink technology for UAS applications. The directorate is working on the low-frequency TRACER radar for foliage penetration and higher frequency VADER radar for better SAR/GMTI resolution. The Northrop Grumman Artemis radar combines high and low frequency modes in one sensor for Sky Warrior-size platforms.

The I2WD has demonstrated an integrated COMINT/ELINT payload aimed at mapping enemy signal sources from a tactical UAV. The objective is a mini-UAS used with ground sensors to geolocate signal sources and counter Improvised Explosive Devices. I2WD was instrumental in rapidly fielding Aircraft Survivability Equipment for manned Army aircraft, and the "Sledgehammer" electronic attack system recently demonstrated on a Black Hawk helicopter may be downsized for UAVs. "We think, as soon as these UAV systems become more prevalent and the capabilities they add to the warfighter are realized, these platforms will have to be protected as well," said I2WD Director Anthony Lisuzzo.

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