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Wednesday, August 1, 2012

Proving Payloads

U.S. Army is leveraging in-house integration and testing capabilities to expedite interoperability for unmanned aircraft systems

By Frank Colucci

A Block II Apache Longbow takes off at Dugway’s Michael Army Airfield as a Shadow unmanned aircraft is readied for flight. The aircraft were linked during at the Manned Unmanned System Integration Capability exercise last year.

The U.S. Army’s Unmanned Aircraft System (UAS) Rapid Integration and Acceptance Center (RIAC) will test the Gray Eagle UAS with the Block III Apache Longbow attack helicopter this June. As part of Block III production prove-out testing, the Apache crew will steer the UAS flight path and operate Gray Eagle sensors through a Tactical Common Data Link (TCDL) and cockpit controls and displays.

“They can connect to our airplane digitally while they’re still on the ground and launch that Apache completely situationally aware... They’re seeing our imagery,” said Lars Ericsson, senior scientist for the Project Manager UAS (PM UAS) at the Army Program Executive Office for Aviation in Huntsville, Ala. The manned helicopter is expected to exercise Level IV control over the Unmanned Air Vehicle (UAV) at distances greater than 50 km and stream stored UAS video to ground stations greater than 100 km away. “To the Gray Eagle, the Apache is just another ground station.”

The RIAC at Dugway Proving Ground, Utah, the UAS Technical and Certification Centers at Redstone Arsenal, Ala., and the Joint Systems Integration Laboratory (JSIL) also at Redstone integrate and test such capabilities. Ericsson noted, “That’s what we serve our customer with — products and effects.”

The customer can be other than the Army. In March, a Shadow UAS dropped a Shadow Hawk laser-guided weapon at a Dugway target to satisfy a Marine Corps requirement. The use of laser-safe ranges at the Army’s Fort Huachuca UAS Training Center and most other test facilities is limited. The RIAC also has airspace, hangars, runways and frequency spectrum to test unmanned Ravens, Shadows and Gray Eagles expeditiously. “We stood up a capability at Dugway for all of our aircraft to be on-site out there and fly out there without a lot of interference,” said RIAC Director Marvin Nichols. “We can fly every type of vehicle we own. It is normal to walk out there at 10 o’clock in the morning and see three different types of UAS flying.”

JSIL technicians in a Universal Ground Control Station run a hardware-in-the-loop simulation at the Redstone Joint Service Integration Lab in Alabama.
At Redstone, the UAS Joint Technology Center/Systems Integration Laboratory (JSIL) and collaborating UAS Technical and Certification Centers support payload development teams. They have hardware-in-the-loop simulations and other tools to integrate air vehicles with other equipment such as the Universal Ground Data Terminal and One System Remote Video Terminal. Army engineers routinely integrate new payloads into existing UAS architectures. “We have a critical mass of hardware and understanding,” said Ericsson. “Once we get ‘paws-on-payload’, the JSIL tends to be where it goes first.”

Nichols added, “We use the RIAC as the end-state of the testing. We use all these other assets to do the up-front integration.” The Technical Center is working on a TCDL modification to link UASs with NET-T networked ground systems. Recent efforts have also sought to connect to UAS datalinks through 3G cellular networks. Three new video compressors are being evaluated against Department of Defense interoperability standards. According to Ericsson, “As we want to move to HD (high definition) sensors and WAAS (Wide Area Airborne Sensor) sensors, there’s enormous pressure on compressors now.”

The RIAC routinely tests Quick Reaction Capabilities and performs technical demonstrations and assessments for sensors, weapons, ground stations and complete systems. While the RQ-7 Shadow and a new TCDL undergo acceptance testing at Dugway, the MQ-1C Gray Eagle flies its third round of post-production testing. The RIAC also enables the Army to fly “off-axis” payloads outside big programs of record. Just what payloads get integrated and tested is determined by PM UAS. According to Nichols, “Within the program office, we have a board that evaluates the capabilities we might have within the limited resources we have. Lots of people come through our doors every day. With an eye on requirements, we prioritize which ones we can address today.”

Integration Insights

Engineers from PM UAS work with the Army Aviation and Missile Research Development and Engineering Center (AMRDEC) and contractor Dynetics Corp. at Redstone

Arsenal to integrate payloads into unmanned systems from different OEMs. “We sometimes use OEMs, but that does get a little harder,” said Nichols. “We used to let the primes do a very large part of this and we used to be scattered.” Before RIAC, UAS integration was done at Fort Huachuca, Ariz., for the AAI Shadow; Cochise College, Ariz., for the Northrop Grumman Hunter; El Mirage, Calif., for the General Atomics Gray Eagle; and Simi Valley, Calif., for the AeroVironment Raven.

“Traditionally, there was much more of ‘let the primes do it,’” said Nichols. More recently, the Army has acquired facilities and intellectual property to do more of its own integration. “We can use the primes for the things they’re the best at and for other work look for less costly options.”

Integration delays also cost money, and according to Ericsson, “There’s nothing more expensive than running late or running over.” The Army scientist noted one of the key enablers for rapid payload integration is interfaces that comply with UAS interoperability profiles or the Defense Information Standard Registry. “If folks come in with proprietary interfaces or they’re not standard, that makes it tougher.”

Other integration complications arise when suppliers underestimate environmental stresses such as the high pre-flight temperatures encountered in Shadow air vehicles in Iraq and the high launch acceleration and vibration forces imposed by the Shadow hydraulic launcher.

Payload-driven changes in flight-critical systems or vehicle mold lines likewise complicate integration. “We have a variety of abilities to modify aircraft or add things,” said Ericsson. However, every air vehicle has a fixed payload envelope with racks and connectors. “When folks are outside that, it obviously becomes more difficult.”

The Army Aviation Engineering Directorate at Redstone has to evaluate air vehicle documentation to establish the airworthiness of changes. More difficulties come from payloads that create extreme electromagnetic or thermal issues or cross security classification levels. Though the Gray Eagle provides significantly greater bandwidth for payload traffic than the Shadow and Raven, available frequency spectrum remains a consideration. “Dugway’s a very good environment, but it may be the only place in America where it’s so relatively easy to get spectrum,” Ericsson said.

The UAS Certification Center at Redstone makes sure payloads adhere to interoperability profiles established by the Army and the Office of the Secretary of Defense. The Northrop Grumman radar on the Gray Eagle is the first Army UAS payload to conform to NATO STANAG 4586 (Avionics, May 2011, pg. 24). PM UAS is part of the Interface Control Working Group including some 100 companies and user representatives to distill new standards.

“We zoom down in on the things that are important to us. It’s a slow, painful process, but crucial to DoD interoperability goals,” acknowledged Ericsson.

Testing Place

The primary mission of Dugway Proving Ground remains chemical and biological warfare testing and training, including development of detectors and protective gear. However, the Army chose Dugway as the site of its Rapid Integration and Acceptance Center in 2009 because of an environment uniquely suited to UAS testing. Some 800,000 acres of Army Proving Ground surrounded by the Air Force Utah Test and Training Range give RIAC ample Restricted Airspace R-Boxes for unmanned aircraft. “We’ve got long legs within that environment to test the datalinks,” Nichols said.

Big ranges safe for laser designation are also valuable for weapons tests such as the first Shadow Hawk drop. “The key thing there was to do laser,” said Ericsson. “Weapons integrations, of all the integrations, are probably among the slowest because of the safety considerations.”

Lockheed Martin Missiles and Fire Control built the Shadow Hawk glide bomb using the control actuation, guidance and control, semi-active laser seeker and outer mold line of the DAGR laser-guided rocket. The company used a subset of the Universal Armament Interface to pass position, velocity and timing data down from the Shadow air vehicle to the weapon. The inert demonstration round impacted within 8 inches of the target. The Dugway demonstration used a ground laser designator, but the Shadow is being integrated with the IAI POP300D sensor payload including a designator.

Existing range instrumentation and new-build infrastructure supports UAS testing at Dugway. PM UAS now has hangars and workshops dedicated to Unmanned Aircraft Systems. Components repaired by UAS prime contractors are reassembled into complete aircraft at RIAC. Michael Army Airfield has an 11,000-foot runway and 9,000-foot taxiway to launch manned and unmanned aircraft.

The Manned-Unmanned System Integration Capability (MUSIC) demonstration last September saw unmanned Ravens, Hunters, Shadows and Gray Eagles linked to Block II Apache Longbow and Kiowa Warrior helicopters and multiple ground users. A Ground Based Sense-and-Avoid demonstration this summer will use two three-dimensional air traffic radars to cue UAS operators in airspace shared with manned aircraft (Avionics, August 2011, pg. 10). “That kind of capability has grown up out there and will be sustained out there,” said Nichols.

Electro-optical targeting boards and other test assets available at Dugway can also be augmented with equipment from other ranges if needed. Army UAS testing continues at other ranges, but according to Nichols, “Dugway for us is the best we’ve ever had... The ground facilities have Afghan-like terrain, best spectrum availability and a great range team — actors to emulate insurgents, vehicles and so forth.” He added, “They’re also the most cost-effective, I’ve ever dealt with.”

The Army PM UAS has worked on payloads for the A160T Hummingbird unmanned helicopter flown by U.S. Special Operations Command. It is also the transition manager for the Autonomous Technologies Unmanned Aircraft Systems Joint Capabilities Technology Demonstration using the cargo-carrying K-MAX helicopter demonstrated at Dugway and now resupplying Marines in Afghanistan. “It’s not about the K-MAX, it’s about the technology you bolt on that tells it where to put the cargo,” Ericsson explained.

Coming up, RIAC will re-test Hindsight, a small Synthetic Aperture Radar on Shadow funded by the OSD Rapid Technology office to detect buried Improvised Explosive Devices. “Sometimes you determine it’s not ready, and you have to take another run at it,” Ericsson said.

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